Depending on the type of Hall-effect sensor, you can use it to measure the magnetic flux or to serve as an on-off-switch. Circuits within the sensor determine the type of output it provides. A linear sensor has a specific positive and negative range, at the ends of which it saturates and provides a constant voltage output. An on-off switch has a specification for the magnetic field needed to turn it on and the field needed for the switch to release. Applications for switches predominate in electronic equipment.

Many Hall-effect switches provide an open-collector current sink (NPN) output you can use to control a digital circuit or to drive components such as a Darlington transistor that operates a relay, an opto-coupler that serves as a galvanic isolator, a solid-state relay that can control a motor or solenoid, and so on. Engineers can buy Hall-effect sensors with different sensitivities and power-supply requirements, and sensors come in a variety of packages from surface-mount devices to complete assemblies ready for use in industrial equipment and harsh environments, as shown below.

A linear, or analog, output can supply a voltage to an analog-to-digital converter so instruments can use the digital result to determine the position of a magnet with respect to a sensor. By connecting the voltage to a comparator, designers can detect when a magnetic field gets above or below a preset threshold.

The on-off sensors have a transfer function--a description of the sensor's response--that shows hysteresis. That means a sensor will turn on with, say, a 60G applied field, but it will not release until the field diminishes to 45G.  Thus you get a "bang-bang" effect, much like a mechanical switch and the switch does not turn on or off for small variations in the actuating magnetic field.

If you'd like to know more about Hall-effect sensors, Honeywell has a 120-page "Hall Effect Sensing and Applications" handbook available for download at: http://content.honeywell.com/sensing/prodinfo/solidstate/technical/hallbook.pdf.

By the way, the Hall effect is not new. Edwin Hall discovered it in gold in 1879 during research for a PhD in physics at Johns Hopkins University. It took some time until semiconductor physics created low-cost Hall-effect sensors available for about $US 1, as shown below.

The next time you drive out of your garage, think about setting up a magnet on the garage door and a Hall-effect sensor on the track to indicate via a light the door has reached its fully opened position. It's less expensive that replacing a door someone backed into as it retracted.  (Images courtesy of Honeywell.)

The latter area got notice recently in a short video on the physorg.com Web site that demonstrates how a swarm of airborne robots can operate with each other and perform complicated movements. Here's the link: http://www.physorg.com/news/2012-02-airborne-robot-swarms-complex-video.html.

Photos by Kurtis Sensenig at the University of Pennsylvania.

This robotics project has its own acronym, SWARMS, which stands for Scalable sWarms of Autonomous Robots and Mobile Sensors, and has a Web site devoted to the project. Learn more at: http://www.swarms.org/. Photos on this site show examples of ground and airborne robots that work together and use Mica2 "motes" to communicate. Crossbow Technology used to produce these wireless-sensor devices but has given up that business. You can find an extensive list of prototype and commercial motes here: en.wikipedia.org/wiki/List_of_wireless_sensor_nodes. Most of the links I tried led to research projects rather than to companies that sell off-the-shelf motes. Of course you could always build your own.

I have had fun working with wireless modules from Texas Instruments and Digi International and I could use them in robotic equipment. Libelium sells a line of Waspmote boards and transceivers, and ANT Wireless has created a protocol for sensor "swarms." Texas Instruments and Nordic Semiconductor have licenses to use the ANT protocol in wireless transceivers. Find more information at: www.nordicsemi.com/eng/Products/ANT and at www.ti.com/lsds/ti/microcontroller/rf_mcu/product_search.page?family=BTANT.  The ANT protocol communicates over a Bluetooth-type channel and does not use IEEE 802.15.4 radios.

Companies such as Texas Instruments and Microchip Technology have their own protocols; SimpliciTI and MiWi respectively, or you can use the basic IEEE 802.15.4 transceivers alone or with a standard ZigBee protocol. The ZigBee software stack can take a lot of code space, so unless you need interoperability with other manufacturers ZigBee devices you don't need it.

If you have an interest in ZigBee sensor networks, take a look at the book, "Building Wireless Sensor Networks," by Robert Faludi, ISBN: 978-0-596-80773-3. I have a new book, "The Hands-On XBee Lab Manual," which should become available in the spring of 2012. It describes how to use the popular XBee modules in 22 lab experiments. ISBN: 978-0-12-391404-0. I have to toot my own horn once in a while.

In addition to operating as an HID with an SPI interface, the chip supplies nine general-purpose I/O pins you can use as you wish, or as chip-select signals for on-board SPI devices. The nine pins also operate with alternate functions such as an SPI Transfer Traffic LED control, a USB Low-Power indicator, and USB Suspended flag. An internal EEPROM lets you save and retrieve configuration, setup, and operational information. Commands transmitted from a USB-host device control I/O-pin operations and memory read/write cycles.

On-chip nonvolatile RAM (NVRAM) saves SPI transfer settings such as SPI bit rate, SPI mode, and chip-select values. This memory also saves information about the GPIO pins to set the type of operations needed, along with I/O-pin direction and I/O-pin default conditions. The MCP2210 stores HID string descriptors that you can change to your own product and company information via configuration-utility software provided by Microchip. When the chip enumerates--essentially gets recognized by the host computer--the host "sees" your information.

Because some designs rely on SPI connections between chips and boards, this new chip will simplify adding a USB connection or replacing an older RS-232-type serial connection to a host computer. The chip's GPIO pins give you extra digital signals to use as you like, which lets you add functions to a design but without needing an extra MCU or USB interface.

Microchip's data sheet, available at: http://ww1.microchip.com/downloads/en/DeviceDoc/22288A.pdf, lists the bit and register variables and settings, and it supplies flow charts that diagram chip operations and responses.

You can buy an MCP2210 Evaluation Kit (part no. ADM00421, shown above) for $US 29.99, at http://www.microchip.com/get/T7QS. The kit's USB board attaches to a small motherboard that supplies an 4-channel, 12-bit ADC, a temperature sensor, an EEPROM, and an I/O expander that connects to eight LEDs through jumpers. All devices use an SPI interface, so if you may connect them to the MCP2210 and communicate with them from a host PC via a USB cable. Or you can leave these devices unused and connect the MCP2210 chip to your own circuits.

Download the free MCP2210 software drivers, dynamic-link library (DLL) and the PC configuration tool from: http://www.microchip.com/get/T7QS.

The MCP2210 comes in a 20-pin SSOP package ($US 1.40 each, 5k units) and in a 20-pin 5x5-mm QFN package ($US 1.52 each, 5k units).  Microchip has samples and production quantities available now.

^{Courtesy of Edmund Optics.}

Norman Edmund started to buy surplus optics from the Frankford Arsenal in Philadelphia, PA during World War II and launched his company in 1942 from an office in Collingswood, NJ. The first mail-order catalog appeared a year later and according to the company, now known as Edmund Optics, it included 1000 items! During the Korean War, the U.S. government repurchased some of the surplus equipment it had sold Edmund.

According to Michael Rivero, who analyzed photographs for NASA, "The inclusion of a TV camera for the moon walk [on the Apollo 11mission] was a last-second decision. The camera was thrown together out of spare parts (including a Barlow lens for an astronomical telescope from Edmund Scientific)." Information from Edmund notes that lens cost 95 cents! (Ref. 1)

The company introduced a helium-neon laser in 1970, and in 1976 the company started to sell the Astroscan, a wide-field reflector telescope that became popular with students and schools. In 1984, the company created Edmund Industrial Optics and started to concentrate more on industrial users, although Edmund Scientific continued to sell kits, telescopes, microscopes, and optical components. In 2001, Science Kit & Boreal Labs (www.sciencekit.com) purchased the Edmund Scientific portion of the company and continues to sell a galaxy's worth of interesting kits and products. You can buy telescopes, microscopes, a water-monitoring kit, and even a kit to make your own hot sauce.

Today, Edmund Optics continues the family name and sells commercial- and research-grade components, lenses, digital cameras, lasers, light sources, spectrometers, and similar products. The company has its own research and optics laboratories and manufactures many of the products it sells. Many members of the Edmund family work at the company. (www.edmundoptics.com) --Jon Titus

Ref. 1. www.washingtonsblog.com/2009/07/is-this-why-the-quality-of-the-original-moon-landing-video-was-so-bad.html. (The article deals with rebroadcast video, not TV-camera optics.)

Below you'll find the course information. You can get credits and a certificate for participating in these seminars.

1. Introduction: Fundamentals of Designing with Microcontrollers

At the end of this session, you will:

a. Understand how a microcontroller differs from a microprocessor

b. Understand the types of analog and digital peripherals on an MCU

c. Understand the types of communication devices available on MCUs

2. Low to Choose the Right MCU for Your Application

At the end of this session, you will:

a. Understand how to specify your requirements and select the appropriate chip families

b. Understand the problems of pin conflicts and how to avoid them

b. Know how to better evaluate development tools and support available from MCU vendors and third parties

c. Know how to look at an MCU vendor's "roadmap" to determine future capabilities

d. Appreciate the important of product support and longevity

3. Successful Software Development for MCU Applications  (I'll include some successful-hardware development here, too.)

At the end of this session, you will:

a. Have learned about the variety of hardware- and software-development tools available

b. Have an appreciation for capabilities of free and paid-for tools, and for third-party support

c. Better understand what you need in as hardware- and software-development tools

d. Understand how to introduce a team to new tools and ideas

4. Fundamentals of Digital Debugging

At the end of this session, you will:

a. Understand the basic techniques used to debug hardware and software

b. Have learned about hardware tools available to assist with debugging work

c. Learn about an inexpensive "secret" debug tool every lab should have

d. Appreciate the use of mixed-signal tools and data-analysis instruments

5. Tricks with the PIC MCUs: Using the Trusty PIC MCUs.

At the end of this session, you will:

a. Have a number of tips and specific solutions to problems, as compiled by technical experts at Microchip Technology.

b.  Learn about other tips for MCU hardware and software use and project management.

Enjoy.

Photo courtesy of Marty Bahamonde/FEMA.

During an emergency, we won't lose all power. Vehicles unable to travel anywhere can yield 12-volt batteries for radio communications and for small power inverters to keep critical medical equipment running. Vehicles will have enough gasoline to keep batteries charged for a few days. After that we will need alternate-charging capabilities, such as PV arrays. Vehicle batteries cannot undergo a deep discharge, so they will need frequent "topping off" charges.

I found a 60-watt battery-charging PV module on the Internet for $260 and I can build or buy a charge controller unit. The combination of the two should let me keep 12-volt batteries charged at least for communication work. Today most communication equipment runs from a 12-volt power supply.  Thankfully I don't have any other equipment that will need power, but I might buy a small 120-volt inverter just in case.

You can find similar backup chargers made for campers, recreational vehicles, and boats. A Google search will locate suppliers. I noticed several on Amazon

Now comes the decision about where to keep a battery-charging PV array. I'll probably put it near our emergency supplies and assume we can get to them, and I'll build an box for the PV array to help prevent damage from things falling off nearby shelves.

Even if you live in an area not threatened by hurricanes, tornados, earthquakes, floods or other disasters, you should prepare for emergency situations that leave you "on your own" for more than a few days. The Federal Emergency Management Administration (FEMA) has a Web site specifically for emergency preparations and planning. Visit: www.ready.gov/.

The city and county of San Francisco have a site, http://72hours.org/, where you can find information about preparations and types of emergencies to prepare for. Many people and organizations emphasize an emergency "kit" for 72-hour (3-day) self sufficiency, but I recommend a kit for at least 10 days. Remember to include medications and accommodations and food for pets. The American Red Cross Web site (www.redcross.org) includes information "Preparing and Getting Trained," that includes emergency-supplies checklists.  You can find equipment suppliers locally or turn to online suppliers via a Google search for emergency preparedness supplies. Some companies sell complete emergency kits, but I found it less expensive to buy supplies individually.

Along the lines of training, I recommend Community Emergency Response Team (CERT) training. For more information, visit: www.citizencorps.gov/cert/training_mat.shtm. Usually a community or local group sponsor CERT classes and exercises. Technically minded people also might consider obtaining an amateur-radio license so they can provide communication assistance in an emergency. The American Radio Relay League provides educational and study materials and oversees a group of volunteers that administer multiple-choice exam tests. (The FCC dropped the Morse code requirement some time ago.) Visit: www.arrl.org/licensing-education-training. --Jon Titus

An advertisement for USB "scope" modules from Chronologic, an Australian company made me think about the feasibility of bench scopes with more than four channels. The company's USB-inSync CL4000 modules let engineers stack as many analog channels as they need (as many as 99) and acquire data through a USB connection. These modules offer 14-bit resolution and acquire signals at 100 Msamples/sec. The buffer memory provides a 128-Mbyte capacity. (Keep in mind that's enough memory for only 64 Msamples because you have 14-bit data.) Each unit handles only one analog channel at a cost of $US1495. That's pricey. (www.chronologic.com.au/)

The USB-inSync technology, though, might make this purchase worth the cost. The basic USB protocol includes no provision for synchronous operations or accurate timing signals among several USB devices. Chronologic's white paper on USB-inSync technology explains the new timing capabilities:

"Each USB-inSync device is equipped with a local clock that is accurately phase locked to that of every other USB-inSync device attached to a given Host PC. Furthermore, each device contains its own ‘real time’ counter that is accurately synchronized to those of every other USB-inSync device. A deterministic triggering system is also provided so that processes can be started and stopped in a precisely controlled manner. These two features extend USB beyond the realms of its original concept and allow new synchronization, control and monitoring possibilities within a distributed PC-based environment."  (For the complete paper, visit: www.chronologic.com.au/whitepapers.html.)

So the cost of the USB scope modules relates directly to the accuracy of timing between modules, which provides a module-to-module accuracy within as little as one nanosecond. Over longer distances, the timing accuracy worsens, but on a lab bench, a nanosecond should suffice. If you need more than the two or four analog channels on your present scope, the USB-inSync module deserve a look. And the modules come with dedicated stand-alone scope software and LabVIEW drivers. Chronologic also manufactures precision-timing devices, so the company engineers know how to make accurate timing work.

A separate input lets you trigger data acquisition based on an external signal or you can set standard trigger conditions such as edges, glitches, and so on, as well as use software to trigger the units. The company's information does not describe how an external trigger propagates through to other modules, so I have asked more information and will include an update as soon as I receive it from Chronologic.

To be fair, you can buy instrument cards that connect to the PXI or PCI bus and digitize five or more analog signals. National Instruments sells a PXI-5105 and a PCI-5105, both of which provide eight analog inputs and sample these inputs simultaneously at 60 Msamples/sec. The PCI version that offers 12-bit resolution and comes with 128 Mbytes of memory costs about $US 6500. The PXI version has the same specs and price, but you need a PXI mainframe and additional components to use this card. The hardware cost equals $US 813 per channel, but without software. (www.ni.com)

NI also sells an 8-bit USB-based module (NI-5133) that digitizes two channels simultaneously at 100 Msamples/sec. The version with 32 Mbytes of memory costs $1544, or $772 per channel. The comparison with the NI-5105 doesn't account for the difference in memory, though.

You can find other USB-based scope pods or modules, but as far as I know, none provide parallel triggering without running the trigger to each module.  If you want to suggest another USB-based scope module, or have some results from hands-on testing, feel free to put your information in a comment for this entry. --Jon

My parents, a lawyer and a school librarian, had little to guide them to gift ideas for sons interested in chemistry and electricity.  So my grandfather, an electrical contractor, mounted low-voltage light-bulb sockets, knife switches, and buzzers on small pieces of wood, and along with some hookup wire and his personal instructions, this assortment of electrical building blocks made a wonderful gift.  I wired and rewired series and parallel circuits and made electromagnets for an Erector set, and amazed friends with a solenoid. Power came from four large 1.5-volt dry cells. At about this time I also received Alfred Morgan's book, "A First Electrical Book for Boys," which I still have.

After demonstrating my "expertise" wiring simple circuits, Santa Claus decided I was ready for electric trains; a used set of Lionel "O" gauge track, switches, and cars, plus a locomotive.  I remember the green board that held the tracks and transformer extending under a living-room couch at Christmas. Dad gave instructions to keep the locomotive speed down and not derail the train behind the couch. In later years my mother told me I would often invite elementary-school friends over to see my trains, but most of the time they would not operate because the layout was continually "under reconstruction," as I modified the electrical wiring or rearranged the track.  I enjoyed working on the setup, but my friends wanted to see the the trains actually go around the track. They didn't want a discussion about what switch would control what part of the layout.

When I was 10 or 11 I got a Gilbert chemistry set for Christmas, along with the book, "Simple Chemical Experiments," also written by Morgan and still on my shelf. The list of necessary chemicals in an appendix includes small pencil marks the indicate I eventually had most compounds available in the basement lab where my brother Chris and I spent most of our free time. The chem lab eventually expanded so much we had to move it across the street to my grandfather's basement where it took one entire wall, as shown in the two photos nearby.  The sophistication of our experiments increased as did our inventory of raw materials.  We discovered a courteous request for small samples of industrial chemicals kept us well supplied. Those days are long gone.

My interests continued to include electronics and I bought and built Knight and Heath kits and requested books about electronics for Christmas and birthdays. I also received gifts of kits such as a Heathkit "Q Multiplier" and a Knightkit VOM. Eventually I got a Hallicrafters SX-110 short-wave receiver and passed the test for a novice amateur-radio license. I got an Eico 732 transmitter, too. One Christmas, Dad gave me the "gift" of a trip with him to Canal Street in New York City. At the time, surplus stores lined Canal Street and the array of electrical, electronic, and mechanical equipment boggled the mind.  Over the years I bought power supplies, relays, switches, and other components with Christmas and birthday money. Mom and Dad had given up trying to figure out what gifts I might like and decided I knew best what I needed for "the lab."  We also visited John Winn & Co. on east 23rd Street in New York and bought chemicals for the lab.

My brother and I went on to obtain Ph.D. degrees in chemistry from Virginia Tech. During our research, though, we became more interested in computers and electronics and made our careers designing electronic equipment, writing software, and writing about electronics.  

Those past Christmases were a happy and fun time and I always remember how my parents and grandparents kindled my interest in science and engineering. 

Renesas provides the TPS-1 chip and what it calls "first-level support" through its sales network. KW-Software provides second-level support and system support based on its competence in automation systems and software. Siemens and Phoenix Contact jointly developed the TPS-1 IC, and Renesas produces it.

The TPS-1 IC includes two Ethernet connection ports with integrated IRT-capable switch and physical interfaces (PHYs), and the built-in PROFINET industrial protocol with RT and IRT support. The chip requires no external RAM. It does provide an SPI port for optional external RAM and 8- or 16-bit parallel buses for connection with a host controller. Because the IC includes an ARM processor core and flash memory, it handles the PROFINET and TCP/IP traffic without intervention by a host controller. You use a "TPS Configuration" program to set various operating conditions, such as the type of interface with the host controller, I/O-pin controls, diagnostic channels, identification and maintenance information, and Ethernet settings. This information gets saved in the TPS-1 boot-flash memory. I'd bet you need a JTAG interface to program the boot flash, but other that JTAG timing diagrams, the KW-Software document includes no programming information.  I would have liked to see some programming examples and to know if Renesas or KW-Software provide a high-level API for Renesas host processors.

Renesas notes in its marketing information that it has a starter kit available to help engineers learn more about how the device operates and how to include it in designs. Unfortunately, the company's "for more information" link simply leads to a short overview and a bullet list of features.  I could locate no technical documents for this kit on the Renesas Web site.  For technical details, visit the KW-Software Web site where you can download a 98-page technical manual. Some of the KW-Software diagrams still include German-language legends, but you can probably figure out their translations. No kit information from KW-Software, either. So, although this chip looks interesting, I'd need more information before investigating further.

Renesas information:  http://am.renesas.com/press/news/2011/news20111121_s.jsp.

KW-Software information: http://www.kw-software.com/com/industrial-ethernet/3021.jsp#3316.

Samples of the TPS-1 device are available now, priced at €19 (approx. $US 24) per piece. Renesas has mass production scheduled for the second quarter of 2012.

The Electric Sheep board uses an ATMega2560 microcontroller pre-loaded with the Mega 2560 boot-loader, and the board provides a USB-host connector for Android devices. The board allows for the creation of accessories for Android using the Arduino integrated development environment (IDE) and HandBag. The latter software helps people create Android applications without having to write Android code. Find more information at the Handbag site: http://rancidbacon.com/p/android-arduino-handbag/. You use the free Arduino integrated development environment (IDE) to create a program to control your actuators, sensors, and measurements on the Electric Sheep board.

The board provides contacts for analog inputs, serial communications, digital I/O, and PWM signals and the pins offer compatibility with add-on Arduino-compatible boards, or "shields." I wish I had an Android smart phone so I could try this board. I also wish SparkFun had more documentation and several sample projects on its Web site. After you buy the board, you're pretty much on your own and must rely on the Android and third-party sites for more technical information and Android code examples. The Arduino and other sites have plenty of information about how to create programs that will run in the ATMega2560 microcontroller.  The Arduino site gives you access to the IDE, too: http://www.arduino.cc/.

Even if you don't want a second career as an Android programmer, take a look at information about the Android Open Accessory Development Kit (ADK). According to the site; The Android 3.1 platform introduces Android Open Accessory support, which lets external USB hardware (an Android USB accessory) interact with an Android-powered device in a special "accessory" mode. When an Android-powered powered device is in accessory mode, the connected accessory acts as the USB host (powers the bus and enumerates devices) and the Android-powered device acts as the USB device. Android USB accessories are specifically designed to attach to Android-powered devices and adhere to a simple protocol (Android accessory protocol) that allows them to detect Android-powered devices that support accessory mode. For more information about the development kit, visit: http://developer.android.com/guide/topics/usb/adk.html. You can find many other Web sites that describe Android Open-Accessory projects, list code examples, and so on.

If you don't need to create an Android-controlled device, the Electric Sheep board can serve as a development platform with all the functions of a host microcontroller and an Arduino USB shield, or add-on board. An Electric Sheep board costs $US 79.95. For more information, visit: http://www.sparkfun.com/products/10745.--Jon Titus

Image courtesy of The Encyclopedia of Alternative Energy and Sustainable Living.

We calculate power from current times voltage, P = I * V, or P= I * E. So, at one point along the curve, the value of I times E produces the maximum power you can obtain from a solar panel, and this point locates the maximum power point (MPP). For a given PV panel, you could use a large variable resistor, measure the I vs. V values for the curve, and put these values in an Excel spreadsheet to calculate the MPP.

To obtain this energy in a useful form, you need a "smart" inverter that tracks the MPP during the day to take into account changes in voltage and current caused by, say, a partly shaded panel or change in the sun's position. The inverter operates based on the average of the power provided by an array of PV cells, so a shaded panel decreases the average power. SolarEdge, for example, supplies a "power optimizer" that connects between panels to ensure operation at the maximum power point. http://www.solaredge.com/groups/powerbox-power-optimizer. Power-One also sells a family of micro-inverter modules that offer a maximum-power-point tracking capability. http://www.power-one.com/renewable-energy/products/solar/string-inverters/aurora-micro/series.

National Semiconductor--now part of Texas Instruments--created the "SolarMagic" family of integrated circuits to help inverter designers maximize the power produced by PV arrays and the National Semi archives provide reference designs and other information that explain how to use the SolarMagic devices.

Application note 2120, "Power Optimizers Partial Deployment for Single String Systems," provides information that can help non-designers better understand the benefits of using smart inverters that make the best use of PV power. http://www.national.com/an/AN/AN-2120.pdf. The paper includes some basic algebraic equations that illustrate efficiency calculations. I found the paper helpful.

National's application note 2124, "Power Circuit Design for SolarMagic SM3320," provides information that will interest electrical engineers who design power-converter and inverter circuits. http://www.national.com/an/AN/AN-2124.pdf. The National SolarMagic chips form the heart of "micro-inverters" that connect to each panel and deliver DC power to a larger inverter. These chips perform the maximum-power-point tracking functions. The app note includes some math and schematics, but even non-technical readers can get useful information from the first three pages.

For a non-technical description of PV power, I recommend the Scientific American blog post, "Invert your thinking: Squeeze more power out of your solar panels," by George Musser: http://blogs.scientificamerican.com/solar-at-home/2009/08/26/invert-your-thinking-squeezing-more-power-out-of-your-solar-panels/. One of the comments in this blog notes the proper way to calculate panel efficiency, which many people get wrong. It isn't simply power out divided by power in.

For technical readers, the National Instruments paper, "Part II -- Photovoltaic Cell I-V Characterization Theory and LabVIEW Analysis Code," includes interesting information about I-V curves and calculations. You don't need LabVIEW software or knowledge to read this paper. Visit: http://zone.ni.com/devzone/cda/tut/p/id/7230.

The paper, "A Guide to Photovoltaic Panels," includes more information as well as a helpful chart that shows times of the year, latitude, and appropriate panel angles. Visit: http://itacanet.org/eng/elec/solar/pv.pdf. I could not find any information about Itaca or what it represents. --Jon Titus

The engineers at DeLorme tackled the problem of lost people with an innovative product that recently won honors from Popular Science magazine. The company's inReach Satellite Communicator uses the constellation of Iridium satellites to communicate a prepared SOS message and remote tracking information to a central location. The pocket-size module has a message-received indicator so hikers know their call for help got through. An internal GPS receiver provides position information and users can turn on remote tracking so friends and family can track positions transmitted periodically every 10 minutes to every 4 hours. Responses to emergency messages come through the GEOS International Emergency Response Coordination Center and SOS messages automatically trigger remote tracking.

You can "mate" the inReach unit with a DeLorme PN-60w GPS unit or with an Andriod phone. The connection between devices lets the inReach satellite transceiver communicate position information and short text messages. The inReach costs $US 250 and requires a subscription to the inReach communication service ($US 10/month). For more information, visit: http://shop.delorme.com/OA_HTML/DELibeCCtpSctDspRte.jsp?section=10820&minisite=10020.

I don't often write about consumer products, but the inReach product seemed particularly innovative for several reasons. First, it relies on an existing satellite-communication network available worldwide. DeLorme didn't have to create its own communication network. Second, it serves a specific purpose and the designers did not aim to make it a "universal" communicator. Instead, they created it to sent a short SOS message. Third, the handheld inReach uses an off-the-shelf Iridium 9602 short-burst data transceiver, which simplified the design. Fourth, the unit provided only four controls and indicators: power, tracking, transmit pre-loaded message, and transmit SOS message. Fifth, it can connect with other products to offer additional message-communication capabilities.

Innovators and entrepreneurs can use the inReach as a model when they create new designs. --Jon Titus

The TI Cortex-A8 processor includes a 128-bit NEON data engine and a floating-point math unit. The NEON data engine acts like a single-instruction multiple data (SIMD) processor that accelerates multimedia and signal processing algorithms such as video encode/decode, 2D/3D graphics, gaming, audio and speech processing, image processing, telephony, and sound synthesis. The NEON subsection provides 32 registers, each 64 bits wide, or you can configure 16 registers, each with 128 bits. The NEON processor uses registers to hold vectors of elements that have the same data type: signed or unsigned values with 8-, 16-, 32-, 64-bit resolutions, and single-precision floating-point values.

The ARM A8 architecture includes a TrustZone IP block that facilitates secure payments and handles digital-rights, but TI's preliminary datasheet does not mention this capability for the AM335x processor family. On the other hand, TI's OMAP3515/03 applications processor, also based on an ARM Cortex-A8 does include Trust Zone capabilities.

The AM335x ARM Cortex-A8 microprocessors gives engineers, programmers, and equipment designers two development-tool choices.  They can "get their feet wet" with the $US 89 BeagleBone (beagleboard.org/bone), an open-source board supported by the BeagleBoard community (www.beagleboard.org).

Or, they can use the AM335x evaluation module that includes a 7-inch LCD touch screen and gives users access to all the AM335x-chips peripherals. The TMDXEVM3358 board sells for $US 995 and it includes TI’s WL1271 single-chip 802.11b/g/n + Bluetooth. The kit package comes with an Android Development Kit and a Linux EZ Software Development Kit for Sitara microprocessors. www.ti.com/tool/tmdxevm3358.

TI’s Linux EZ SDK and support for Android 2.2 are available free from TI, starting in December 2011. The company expects to support Windows Embedded Compact 7 in the first quarter of 2012 and support for QNX, Mentor and Wind River real-time operating systems will be available later in 2011. Samples of the XAM3358ZCE and XAM3359ZCZ are available now.  Engineers can expect to see reference designs based on the AM335x ARM Cortex-A8 microprocessors on the TI Web site starting later in 2011. --Jon Titus

p.s. TI recently announced a new version of its Code Composer Studio (ver. 5): processors.wiki.ti.com/index.php/Category:Code_Composer_Studio_v5.

In a report from EnerNex, a research, engineering, and consulting firm, SDG&E would assess a network-use charge based on the average hourly amount of power exchanged between a customers’ solar-energy system and the power-distribution grid. An average hourly flow of 1 kW would result in a monthly charge of $35.44 under the current proposed rates for 2014.  The proposed charges would cover:

1. Equipment and maintenance impacts due to reverse power flow.

2. Equipment and maintenance impacts due to operational voltage regulation.

3. Voltage fluctuations due to intermittent generation export to the system.

4. Distribution system capacity impacts.

Of course electric-power-distribution networks require maintenance and upgrades, but electric-company customers already pay for this in their monthly bills.  A family I know pays about $US 450 per year for "delivery" at a vacation home. Actual power use during summer vacations amounts to less than $US 50. But the power lines remain connected and available for use at any time.

Information provided by Mitsubishi explained one problem involved when PV equipment provides reverse-power:

The ability to sell power is one of the benefits of installing a photovoltaic system. However, power grids are not been designed for reverse power flow; they act more like one-way streets. To reverse the flow, the PV-generated power must exist at a voltage slightly higher than the grid voltage, and distorted waveforms and other phenomena specific to photovoltaic power could impact the grid. With small systems for the home (3kW), this is not particularly a problem, but if the medium- and large-scale systems used by buildings and factories become more widespread, the impact of reverse power flow on the grid emerges as a problem that cannot be ignored. Mitsubishi Electric is conducting research and testing aimed at developing systems that minimize disturbance to the grid's power quality.

People in the photovoltaic industries worry that the additional charges will affect their business because potential customers will choose to not connect to a power grid or install only a power-backup system--and thus spend less on equipment--or forego installing PV equipment. On the other hand, power companies and their customers worry about how reverse power will affect the quality of electric power on the grid. Both sides have legitimate concerns and both sides should be willing to pay the cost for research and equipment upgrades needed to accommodate the other. Long-term gains should balance short-term expenses. --Jon Titus

References:

Solar Industry: www.solarindustrymag.com/e107_plugins/content/content.php?content.9095.

Net metering: en.wikipedia.org/wiki/Net_metering.

EnerNex: www.enernex.com/blog/proposed-sdge-rate-change-upsets-solar-photovoltaic-owners/#!/.

Mitsubishi: www.mitsubishielectric.com/company/csr/ecotopics/pv/quality/index.html.

Texas Instruments has taken a different approach called StarterWare that gives engineers and programmers the capability to work with processors and have easy direct access to I/O devices and peripherals, but without imposing the processor overhead or learning curve associated with an OS. According to TI, the free StarterWare software packages include user-friendly, production-ready software for engineers who will use TI's Sitara 32-bit ARM microprocessors (MPUs), C6000 digital signal processors (DSPs), and DSP + ARM devices. And StarterWare allows for easy migration to other TI embedded devices.

StarterWare's application programming interfaces (APIs) let people directly configure and interface with peripherals rather that flip bits in configuration registers. In addition, the package--again, it's free--includes "lightweight" software stacks for USB, network, and graphics functions. And according to TI, "Example code and application notes included with StarterWare reduce development time up to 10X."

Because engineers and programmers no longer have an operating system between their application code and chip hardware, they can fine-tune how their code interacts with the CPU, peripherals, and memory. TI's announcement of the StarterWare packages claims it can reduce system latencies up to 500 fold compared to running an application under Linux.

Find general information about StarterWare at: focus.ti.com/general/docs/gencontent.tsp?contentId=142071. From there, you can go to individual pages for the Sitara ARM-family MPUs, C6000 DSPs, and DSP+ARM processors. At the Sitara page you can download the free software and learn about what that package contains. Several images show the relationship of the StarterWare to middleware stacks, CPU configuration, hardware, and your application code. You can read about the StarterWare features, learn what each processor package includes, find technical documents, connect with several TI Wikis, read about related products, and check out videos and blog entries. In short, TI has not only simplified using processors without an OS, but has made it easier to get started. You can spend more time on your designs and less grappling with  learning how to use an operating system. --Jon Titus

p.s.  For the main StarterWare Wiki, visit: processors.wiki.ti.com/index.php/StarterWare_Getting_Started_01.00.XX.XX. Lots of good information there to get you off to a fast start.

Thankfully, our subdivision has only 26 homes and the builder's CC&Rs expired after about five years, so we can do pretty much what we want with our property. Not everyone has such good fortune. News stories appear again and again to describe the travails of people who erect PV arrays only to have a homeowner's association sue for their removal. Before you give PV arrays consideration, ensure applicable CC&Rs don't interfere with your plans.  If you bought your home some time ago, you might have forgotten CC&Rs agreed to during the real-estate closing. Also, your homeowners' association (HOA) might have adopted additional bylaws and regulations by authority vested in them through the CC&Rs. Do your homework first.

Second, check with your town planning and zoning departments to determine if any bylaws govern PV arrays and solar collectors. Your locality might have adopted more restrictive building and electrical codes that those for your state. Also, building inspectors can help you understand local and state building requirements for PV arrays and the credentials, permits, and insurance needed by installers.

Third, find a local attorney who has experience with HOAs and overcoming objections to property changes. This attorney will have suggestions about how to work with the HOA and how to approach it with a proposal. You might not need more legal assistance, but it always helps to have some backup if things take a turn for the worse. An attorney can refer to any case law that involves HOAs and your desire to install PV equipment. In some cases, if a HOA has not applied rules and regulations fairly, has ceased to elect members, has not enforced rules or collected fees, and so on, they could have lost their authority to do so.  In a case I know of, members of a community got so fed up with HOA board of director's arbitrary enforcement and nebulous standards that they voted to disband the HOA altogether.

Fourth, I suggest you talk with your neighbors about solar energy and find out how they feel about renewable energy and PV arrays in general.  Would they consider installing PV arrays if allowed?  How do they think they should appear?  Where might they install them?  Do they have any experience with renewable energy?  This information helps you gauge whether you'll find hostility if you start a project or try to work with your HOA. Having neighbors approval can help during any HOA- or city-approval steps.

Fifth, determine if the HOA has approved any other PV installations and under what conditions. Then you have more information--and possibly a precedent--when you prepare a proposal and ask for a hearing.  You also will need a building permit in most localities.

Some states have started to enact legislation that will over ride CC&Rs and HOA bylaws to allow PV-array installations. Check with your state representatives for an update on any changes to laws. In a California case, a homeowner's group decided against approval of a PV array because they didn't like the color. The city overrode that decision, based on a law that, "...prohibits cities and homes associations from restricting solar panel installations, unless they pose a risk to the health or safety of nearby residents."

Do a Google search for photovoltaic and "homeowner association" to get a better understanding of what you might face. Remember not all PV arrays must go on a roof. If you have sufficient property, you could mount at least some arrays at or near ground level. HOAs might not object to such an arrangement.

Always keep an open mind and understand you'll find some difficulties along the way. --Jon Titus

References:

Solar Access Laws: www.dsireusa.org/solar/solarpolicyguide/?id=19.

A Comprehensive Review of Solar Access Law in the United States: www.solarabcs.org/about/publications/reports/solar-access/index.html.

Caffrey, Kristina, "The House of the Rising Sun: Homeowners’ Associations, Restrictive Covenants, Solar Panels, and the Contract Clause," lawlibrary.unm.edu/nrj/50/3/07-caffrey-house.pdf.

If you plan to store energy from photovoltaic arrays in lead-acid batteries, you must follow safe standard operating procedures. An article in the September EC&M magazine, "Get to Know Your Battery," shows a person working on lead-acid batteries and wearing a clear face protector, a plastic or rubber apron, and rubber gloves. Unfortunately, this photo shows exposed bus bars between batteries, a situation just waiting for a a metal tool to cause a catastrophic short circuit. Information from the University of Wisconsin notes 2300 people in the US suffer injuries related to improper handling and use of lead-acid batteries. Acid burns to faces and eyes make up about half of these injuries. For the ECM magazine article, visit: ecmweb.com/ops_maintenance/get-to-know-your-battery-20110901.

Here's an example of an exploded lead-acid battery. Courtesy of Ray Vaughan.

You can find battery-safety information on the Internet and your battery-manufacturer's Web site should also provide information about safe battery handling.  Below I have listed some good resources. I welcome additions to this list:

"Battery Safety," CCB Industrial Battery Co. www.battery-oem.com/tech/battery-safety.htm.

"Battery Safety," Ray Vaughan. www.rayvaughan.com/battery_safety.htm. Good photos of an exploded lead-acid battery. I had a similar experience with a car battery, but the case simply split. I cannot emphasize strongly enough the need to work with batteries in well-ventilated areas.

"Using electric storage batteries safely," Health and Safety Executive, UK. www.hse.gov.uk/pubns/indg139.pdf.

"Lead Acid Battery Maintenance and Safety Protocol," University of Wisconsin. www.wisconsin.edu/oslp/em/compliance/battery_leadacid.htm.

Standardization organizations such as the Institute for Electrical and Electronic Engineers (IEEE), the National Fire Protection Association (NFPA), and the International Electrotechnical Commission (IEC) have information and standards, but you must pay to access them or obtain copies. --Jon Titus

For several years, Rick Hully, the founder of Gruntware, Inc., has compiled a searchable database of information for over 16,000 MCUs from 25 semiconductor manufacturers. And you can use his Gopher Web Plus search for free.  To perform searches, visit: http://gruntwareinc.com. You can select from 110 normalized search parameters. That means Hully has performed parameter conversions to allow "apples-to-apples" comparisons. (Hint: start with as broad a search as possible and narrow it in subsequent searches.)

You can choose the search criteria based on individual manufacturers and chip capabilities.  I searched for 8051-type MCUs that include an Ethernet port and the Gopher search engine found three part numbers. Click on a part number and you go to another display that links to the manufacturers' Web sites and the part's data sheets. The display also lists hot links for related hardware, such as device programmers, JTAG pods, and evaluation boards, as well as third-party software and programming tools, and any applicable real-time operating systems. According to Hully, the types of third-party tools include TCP/IP stacks, file systems, web-server tools, performance analyzers, modeling tools, and debuggers. Links for those items take you directly to the manufacturers' or sellers' Web sites. Hully also noted the Gopher Web Plus site includes over 245,000 links to more information.

A link to the Octopart Web site provides availability and price information for MCUs and development tools. So you know what companies have products in stock for immediate delivery, and you can quickly connect with a vendor to make a purchase.

The free Gopher Web Plus tool does not include all normalized characteristics in the Gopher database, though, and it does not let you identify pin conflicts that could occur if peripherals you need share a pin. Find these additional search functions and the pin-conflict tool in the Gopher PC edition, which costs $US 299. In my opinion, the analysis of pin conflicts alone makes the Gopher PC edition an inexpensive purchase. For a comparison of the free Web-based search engine and the Gopher PC edition, visit: http://gruntwareinc.com/GopherPC/CompareGopherProducts.html.

May your lab time grow longer, and your MCU-search times grow shorter. --Jon Titus

Imagine what lightning could do to a PV array and your associated electronic equipment. I cannot stress strongly enough the need for proper lightning protection.  You can find several good Web sites that explain proper grounding techniques and I'll list below some of the key concerns and suggestions:

1.  Metallic PV mounts, supports, and frames should always have an earth ground.  In most cases you will need several long ground rods to provide a low-resistance path for lightning.  If lightning can find a lower-resistance path, it will follow it.  Some literature recommends several lightning rods and the use of a chemical such as salt (sodium chloride) or copper sulfate to increase local conductivity. That might help, but adding more ground rods nearby will likely work as well and cost less. Connect these ground wires with short runs of the thickest possible copper wire and use properly rated clamps.

2.  Hardware and home-improvement stores sell clamps you could use, but they might not have the proper rating for exterior use and for use with ground rods.  Do not use clamps made for conduit and that use steel screws. A proper bronze ground clamp forces a ground wire against the rod for a solid copper-to-copper connection. If you plan to bury the clamp and the conductor that links all ground rods, purchase clamps rated for direct burial.

3.  Always use the thickest conductor possible to connect equipment grounds to your ground rods and use one point as the central ground for all equipment. Think of the ground as the hub in a wheel with spokes that represent the individual ground wires. If you do not have a central ground, your equipment might include a "ground loop."  This type of loop provides an alternate path to ground as shown in the diagram below.

A single-point ground (top)  prevents ground a ground loop (bottom) that can let hundreds of amperes flow during a lightning strike.

During a lightning strike, one end of the loop can have a potential (voltage) hundreds if not thousands of volts above the other and the potential difference lets current--lots of it--flow.  That current can seriously damage or destroy electrical and electronic equipment. Always aim to eliminate ground loops.

4.  Do not use copper ground wires with a gauge above 10; for example, 12 or 14 gauge. The thicker the ground wire, the better.  I have used braided wire "straps" to ground antenna poles and radio equipment. The braid makes it easier to route a ground line through tight places. A 25-foot spool of 4-gauge grounding strap costs about $100.  Braided strap provides copper conductors plated with tin. This material will oxidize outdoors, though.  Check with a licensed electrician about the use of a braided ground for lightning protection.

5.  Install lightning-protection devices on your AC and DC lines. These devices, often called lightning arrestors or surge suppressors, include an element that will shunt an over voltage to ground. A nearby lightning strike can cause a surge in electrical equipment. These devices do not protect against a direct lightning strike, however.  In my first home, a lightning strike one block away damaged our TV set and electric range.

6.  Ground any exposed metal components.

Please use the information above as guidelines.  Consult with a licensed electrician or a professional engineer before you work with electrical equipment. Observe safe workplace practices when you perform your own electrical work. If in doubt, work with a professional.

Reference:

"All about lightning and lightning protection," www.windsun.com/Photovolaic_Systems/Lightning_Protection.htm.

The total cost of ownership includes two main categories. First, the acquisition cost and second, the sustaining costs.  The acquisition costs seem easy to compute because you can look at a residence and think about the steps and costs involved, from getting building permits, hiring a lawyer to work with your homeowner's association, and adjusting homeowner's insurance to digging footings for ground-mounted PV arrays, planning for PV arrays mounted on a roof, and determining where backup batteries will go to ensure safe conditions.  These costs also include power inverters, wiring, electrician contracts, installation hardware, equipment rentals, delivery costs, sales taxes, and unexpected expenses that arise during installation. You can't plan for an installer who puts a ladder through a window, or someone who incorrectly wires and burns up an inverter. Can you insure against them? It depends.

The sustaining costs create an accounting challenge because you can't plan for every contingency. But you should include the costs to maintain your PV arrays, keep them clean, have them inspected periodically, replace defective or damaged arrays, possibly replace batteries, repair an inverter, prune trees to maintain sunlight on your array, pay for a neighbor to prune his or her trees (if possible), and so on.

When you look at PV arrays, equipment, hardware, and other components, ask about the expected lifetimes. This information can help you plan when to schedule maintenance or replacement. PV arrays, for example, deteriorate over time and their efficiency can decrease by sizable amounts. These days, money set aside for repairs and maintenance does not earn must interest in a bank account, so account for the present value of money, too.  That means, if you have a dollar in savings today, how much will it be worth in five or ten years.  Inflation always cuts into the value of money, although many experts expect larger markets for PV equipment will drive costs down. Still, overall you can expect to pay more for the same equipment and services purchased five to 10 years from now.

I don't want to discourage anyone from installing a PV system, but I always encourage realistic analysis rather than speculative thinking.  As you look at a potential PV system, examine it from many angles. Even if a PV system doesn't appear economical, once you know the total cost of ownership, you might decide to proceed just because it strikes you as the right thing to do. --Jon Titus

The Quick Start guide gave good explanations of steps needed to flash LEDs and change text on the board's small backlit LCD. But that's as far as the instructions go. They provide no description of additional tutorials, lessons, or reference information, which means your hands-on experience will end without a lot of perseverance. You can get past this roadblock, but it takes time and effort you might not want to put into the task.

For guidance, I looked at code for the demo program but found it overly complicated. The kit documents lacked flow charts or descriptions for the various files used in the overall program.  It would have helped to have a "next steps" sheet that points people to specific manuals and documents, as well as a description of the files needed for a do-it-yourself programming example.  Likely the HEW manuals provide some basic information, but unless you know such manuals exist and where to find them, you'll waste a lot of time.

The demo program includes ToggleLED() and FlashLED() function calls, but without much explanation. I had to look through the flashLED.h header file and the flashLED.C file to locate commands that get defined in the Renesas Peripheral Driver Library.  Information about that library never appeared on the RX62N main page.  Eventually I uncovered the 359-page document, "Renesas Peripheral Driver Library User’s Manual, RX62N, RX621 Group," which has the document number: R20UT0084EE0104.  The peripheral-driver library (PDL) simplifies control of interrupts, peripherals, I/O ports, DMA channels, and so on, but I spent a lot of time going in circles until I found the manual. If you plan to investigate the hardware in detail, print the "Renesas Demonstration Kit (RDK) for RX62N User's Manual: Hardware," publication REU10B0009-0100.

The hardware guide includes helpful information about components on the board, expansion headers, jumpers, and settings. But without a schematic, I couldn't determine   the I2C-bus address of the ADT7420 temperature sensor or the ADXL accelerometer chip. Each sensor got only a one-sentence description in the hardware guide.  Eventually I located the sensor-register information in the respective .h file for each sensor.  Likewise, information explained everything about the 12 LEDs, except the most important specification: what I/O port and bit each LED connects to.  I had to get the data sheet for the MCU and relate I/O pin numbers to I/O ports and bits.  Renesas could make that type of information easier to find and available in the printed hardware guide. Overall, Renesas did a nice job with the hardware, but the documentation and examples need a lot of work.

For more information, visit: http://am.renesas.com/products/tools/introductory_evaluation_tools/renesas_demo_kits/yrdkrx62n/yrdkrx62n.jsp.

Team Missouri (Missouri University of Science & Technology and the University of Missouri-Columbia) built this home for the 2009 Solar Decathlon.

The Solar Decathlon 2011 runs at West Potomac Park in Washington, D.C. from September 23 through October 2, 2011, with free admission. Visitors can tour the houses, gather ideas for their homes, and learn how energy-efficient designs can help them save money. Project judging marks teams in 10 areas, with a maximum of 100 points:

• Affordability
• Appliances
• Architecture
• Comfort Zone
• Communications
• Energy Balance
• Engineering
• Home Entertainment
• Hot Water
• Market Appeal

Learn more about the biennial competition at: www.solardecathlon.gov/contests.html.

The rules for competitors are strict and lengthy (70 pages worth), but teams have two years to complete a project. The competition has its own building code, too.

Although I recognized the names of several universities, I was surprised that some well-known engineering schools such as Virginia Tech, MIT, Cal Tech, Berkeley, and Rensselaer Polytechnic Institute weren't on the list of competitors.  (Maybe they participated in previous years.) So perhaps that's an opportunity for students, parents of students, and alumni to spark interest in the 2013 competition. The request for proposals for that competition closes on November 10, 2011.  Accepted proposals will include two $US 50,000 grants for the top 20 teams. You must read the particulars to find out more about how to start a team, sumbit a proposal, or get involved as a supporter.  No matter whether a team wins the competition, it seems like a worthy effort. --Jon Titus

Hydrogen gas, proposed as a fuel for vehicles and used in fuel cells has a similar problem; how to store it safely and in a way that will rapidly release the gas. Scientists at the US National Institute of Standards and Technology (NIST) have discovered molecular scale "veins" of iron that permeate grains of magnesium might enhance the value of magnesium as a practical material for hydrogen storage.

This diagram illustrates the iron veins in a magnesium granule (right).  The abbreviation TM stands for transition metal, one of a series of elements such as chromium, manganese, and nickel.

By the way, many people think of hydrogen as a "free" fuel, but like any fuel, it comes at a cost that depends on the method used to create it.  The cost involves dollars as well as environmental concerns about the sources of energy needed to produce the hydrogen.

According to Leo Bendersky, a materials scientist at NIST, the mix of iron in magnesium could overcome safety problems. The combination of lightweight magnesium (atomic weight 24.3) with small amounts of iron will quickly absorb and release enough hydrogen to make possible a practical "gas" tank for hydrogen-based vehicles. Grains of pure magnesium without iron veins will absorbing hydrogen gas, but only when subjected to high temperatures and pressures do the grains store enough hydrogen to power a car for a few hundred kilometers between hydrogen fill-ups.

According to Bendersky, "Powder grains made of iron-doped magnesium can get saturated with hydrogen within 60 seconds and they can do so at only 150 degrees Celsius and at fairly low pressure, which are key factors for safety in commercial vehicles." That still seems hot to me, but perhaps continuing research will reduce the 150-degree C temperature to a level that doesn't require the added weight of insulation and electrical energy to heat the gas tank to this temperature.  Water boils at 100 degrees C.

According to NIST a practical hydrogen-absorbing material must hold at least six percent of its own weight as hydrogen gas and "gas stations" must safely refill a hydrogen tank in about the same time it takes to fill with gasoline today. And according to Bendersky, the magnesium-iron grains could hold up to seven-percent hydrogen by weight.

By my reckoning, if you have 45.4 kg (100 pounds) of magnesium, it would hold about 3.2 kg or about the equivalent energy in 3 gallons of gasoline. So, hydrogen still has a long way to go before it powers most consumer vehicles. But at least we can store it safely and not as a liquid for use when only a fuel cell will do. --Jon Titus

"Battery Power for Your Residential Solar Electric System," from the National Renewable Energy Laboratory at the US Department of Energy provides a 2-page paper about battery use, purchase, storage, and cost as well as several battery tips.  www.nrel.gov/docs/fy02osti/31689.pdf.

"A Homebuilder's Guide to Going Solar," also from the NERL provides information for builders and solar-energy-system installers about how to get the most energy from solar power and how to design and construct homes to maximize solar efficiency. For a copy, visit: www1.eere.energy.gov/solar/pdfs/44792.pdf.

The NERL has a library of useful and interesting solar-power resources. For a list of the most popular, visit: www.nrel.gov/publications/popular_publications.html.

The Office of Energy Efficiency and Renewable Energy (EERE) within the US Department of Energy provides many resources individuals can use to learn more about solar power.  Visit the EERE Web site at: www.eere.energy.gov/.  Find the publication and product lists at: www1.eere.energy.gov/library/default.aspx?page=7. You can read all documents online or request paper copies of some for delivery by mail. The library of documents lets you browse by topic and also indicate the type of information you seek, such as Consumers and Homeowners, Home Builders and Renovators, and so on. While browsing, I came across "Homeowners Guide to Financing a Grid-Connected Solar Electric System," which offers useful information.

If you go to the US Department of Energy Web site at: www.doe.gov/, you can search by US state to find information about solar-energy programs, projects, regulations, and rebates (if any) in your state. For Utah, the site located 89 links, although some dealt with grants, news, and large solar-energy projects.

The Web site, "Go Solar with Get Started With Solar!" gives you one person's perspective on a do-it-yourself solar-electricity project with much helpful information, photographs and comparisons to approaches to solar energy.  Find the site at: www.getstartedwithsolar.com/.  I wish the author has identified himself or herself because they deserve credit for putting so much information online.

As you plan a photovoltaic system, consult with your municipal building department about local rules and regulations that supplement the National Electrical Code.  You want to ensure a solar-energy system meets building codes.  These codes help protect your investment and lives.  The building inspectors will have a copy of the National Electrical Code (NEC) you can peruse and a local library might have a copy.

The National Fire Protection Agency publishes the NEC ($US 85), which is not current with the 2011 edition.  Find more information at: www.nfpa.org.

If you have a resource to share, please add a comment, give the resource, and include a URL or link.  I'm particularly interested in photovoltaic topics such as grounding, ground-fault protection, and consumer safety.. --Jon Titus

A cable provides a USB connector at one end and 10 individual wires at the other, the wires terminate at insulated female contacts that fit onto pins on 0.1-inch (2.45 mm) centers. The USB connector contains an FT232H USB interface chip that handles all USB signals and protocols so you can use the cables with standard synchronous-serial interfaces or you can create a proprietary synchronous-serial protocol. Cost: $US 26 per cable.

You might wonder, "Why 10 wires for these serial signals?" The connections include four general-purpose I/O lines as well as ground and a power output.  Those I/O pins can come in handy for proprietary controls.

FTDI supplies free SPI and I2C drivers and APIs in dynamic-link libraries (DLLs) for Windows and Linux. User Guides for I2C and SPI communications document the API functions and parameters, so you can easily link your code with hardware. As of mid August 2011, FTDI's Web site doesn't list any JTAG APIs or documents. Perhaps someone will now take advantage of the USB-to-JTAG capability to design inexpensive programming and debugging interfaces and JTAG-control software for microcontrollers and FPGAs.

The links below take you to DLL software and manuals for I2C and SPI connections:

For SPI code and manual, visit;

www.ftdichip.com/Support/SoftwareExamples/MPSSE/LibMPSSE-SPI/libMPSSE-SPI_DLL_Windows.zip

www.ftdichip.com/Support/SoftwareExamples/MPSSE/LibMPSSE-SPI/libMPSSE-SPI_DLL_linux.zip

www.ftdichip.com/Support/Documents/AppNotes/AN_178_User_Guide_For_LibMPSSE-SPI.pdf

For I2C code and manual, visit:

www.ftdichip.com/Support/SoftwareExamples/MPSSE/LibMPSSE-I2C/LibMPSSE-I2C_DLL_Windows.zip

www.ftdichip.com/Support/SoftwareExamples/MPSSE/LibMPSSE-I2C/LibMPSSE-I2C_DLL_Windows.zip

www.ftdichip.com/Support/Documents/AppNotes/AN_177_User_Guide_For_LibMPSSE-I2C.pdf

If you use one of these cables either just for a test, or in a design, I'd like to know how well the software and hardware worked. --Jon Titus

ARISSat-1 design-team leader Steven Bible started the Chips in Space Blog (http://www.eetimes.com/electronics-blogs/4218141/Chips-in-Space) on the EE Times web site to educate and entertain readers via the story of how he and his colleagues built the satellite and the challenges they faced.  Bible also analyzes the satellite's deployment and operation. To learn more about the ARISSat-1 project and see photos of the satellite in orbit, visit: http://www.arissat1.org/v3/.  You'll find interesting information about the satellite design, photos, and design-review slides.

Here's the ARRISSat-1 in its protective white cover on the International Space Station. Image courtesy of ARISSAT1.org.

Amateur-radio satellite projects actually started in 1961 with the insertion into orbit of the Orbiting Satellite Carrying Amateur Radio (OSCAR) unit that continuously transmitted the Morse-code greeting "HI," received as dit-dit-dit-dit  dit-dit. OSCAR made over 300 orbits of Earth before it burned up in the atmosphere. Today, AMSAT, the Radio Amateur Satellite Corporation, oversees many satellite projects, of which ARISSat-1 is only the latest. For years amateur-radio operators have communicated via satellite links designed and built by other radio amateurs and engineers who volunteer their time and energy to satellite projects. Satellite communications require only modest equipment--mainly a good antenna or two and a sensitive receiver. Find the AMSAT Web site at: http://www.amsat.org/amsat-new/. This site provides information about the radio transmissions from the ARISSat-1 that you might pick up.

Since 1961, satellite enthusiasts have created more than 100 satellites, although some failed to reach orbit or failed prematurely. And amateur-radio operators from many countries have created and built satellites. Most satellites hitch a ride on civilian or military missile launches--the amateurs don't build their own rocket engines and guidance systems!

I've held an FCC amateur-radio service license (KZ1G) since the early 1980's and continue to enjoy the hobby.  It's likely you can find an "outlet" among fellow ham-radio operators for whatever aspect of electronics you want to explore--digital communications, digital-circuit design, radio-frequency circuit design, hands-on projects, antennas, microwave communications, searching for "hidden" transmitters, public-service communications, emergency communications, remote control, Internet communications, and so on.

The prepackaged electronic kits of decades ago might be long gone, but many people still enjoy electronics and communications as a hobby.  To me, ham radio is the ultimate outlet for electronic creativity as a hobby. The American Radio Relay League (ARRL) has a lot of helpful information about how to get started and how to obtain a ham-radio license: http://www.arrl.org/new-to-ham-radio.  We old timers had to pass a Morse-code test, but that requirement got dropped some time ago. You can find online the pools of questions asked during exam sessions administered by volunteers at local radio clubs. The ARRL and other groups also provide study guides and sample questions for you to study.  Have fun. --Jon Titus

Manufacturers of inverters might include EMI/RFI filters in their circuits, but at times you need a supplemental filter to further attenuate conducted noise. Companies such as Schaffner and TE Connectivity produce a wide range of filters, some specifically designed for use with PVs.  These filters allow high DC currents to flow from a PV array to an inverter as they attenuate a broad spectrum of EMI/RFI signals that could flow from the inverter out to the PC array.  Inverter efficiency increases with the switching frequency of its switching circuits, but component characteristics can limit switching frequencies to a few 10's of kilohertz, although harmonics can cause EMI and RFI at higher frequencies. Some inverters can operate at 100 kHz or above.

Thus, if you need a filter you must know the switching frequency of your inverter to match it with the specs for a filter.  Filter manufacturers can provide charts of frequency vs. attenuation (in decibels) that show how well a given unit filters at specific frequencies. The charts might show attenuation based on several operating conditions and impedances of the PV array and the inverter.

When you buy an inverter to put PV power on the grid or a battery-management system to store energy in backup batteries remember that the lines between them as well as the PV array can "broadcast" EMI/RFI.  Check with equipment manufacturers about the need for filters and ask them to explain how well they reduce EMI/RFI emissions.  They should have facts, figures, and charts.  Ask about the standards they comply with and look for the CE mark that should indicate compliance with international electromagnetic-compatibility (EMC) standards.  Even though equipment will meet standards in a lab, operating under some field conditions might alter how it behaves.

But according to Northern Arizona Wind & Sun (Flagstaff, AZ), FCC regulation Section 15B that pertains to consumer electronics does not apply to DC or PV, so the latter can get away with EMI/RFI emissions that your TV or laptop PC couldn't.  So, manufacturers of solar-energy electronics might not pay attention to ways to cut conducted emissions.

For more information about reducing EMI/RFI, see "Reducing Electronic Interference in Solar Electric Systems," at: www.windsun.com/General/PV-EMI.htmwww.windsun.com/General/PV-EMI.htm.  --Jon Titus

If you have a PV array, store energy in batteries, and use an inverter to connect power to your home wiring, you should have an easily accessible system cut-off switch for firefighters.  Otherwise, when they cut off the power company's connection, your PV system will cut in and supply backup power.  Firefighters might not know some of your household circuits still present shock hazards.

Even with a cutoff, a large PV array can still deliver high DC voltages to a charge converter or high current to batteries.  So a PV system also should have a DC disconnect rated for the current and voltage present in your system.

The NEC provides many examples and diagrams of ways to disconnect PV systems, batteries, inverters, and charge controllers.  As mentioned in an earlier column, the document, "Photovoltaic Power Systems and the 2005 National Electrical Code: Suggested Practices," By John Wiles provides much practical information as well.  You can download the document at:  http://www.altestore.com/store/media/pdfs/photovoltaic_NEC_code_practices2005.pdf.

PV equipment and cut-off switches require labels that specify conditions such as maximum operating current and voltage and short-circuit current.  You should use large label on cut-off switches, circuit breakers, and components that firefighters and rescuers can easily read.  Some reflective tape might assist emergency people, too.  The information on such labels could save your life and the lives of first responders.  How do you disconnect all the power in your PV equipment? --Jon Titus

Even if you live in an area with frequent rain, don't count on nature to keep panels clean. In my location, high winds during rain storms turn drops of water into mud that cakes dirt on glass. Tap water usually cleans glass effectively either alone or when used with a glass cleaner.  If you have easy access to your panels, use a squeegee to remove water after a cleaning. Do not use any material that leaves a film on glass.

Use solvents recommended by the manufacturer to remove tree sap or other sticky materials.  (I know your PV panels aren't under trees, but  wind can blow "stuff" far and wide.) I have used a dilute solution of trisodium phosphate (TSP) in water to remove oil and grease films from glass.  It works effectively and doesn't harm plants, but in concentrated solutions, it can remove paint.  Hardware stores often recommend TSP as a good grease "cutter," but it might not work well on all PV panels.  Ask your panel manufacturer how to remove any oily film from your PV array.  Oil-furnace smoke, for example, can produce a film that might not yield to the usual glass cleaners.

I have heard of cleaning devices that spray clean water on inaccessible PV arrays to help clean them, but I don't know of any commercial sources for such cleaning systems or equipment. If you do, please leave a comment or any information about how you clean PC panels.

If you live in a place that gets snow, keep a long-handle brush handy, too.--Jon Titus

Bob Pease was a one-of-a kind engineer and you can read his obituary and comments at: http://www.edn.com/blog/Anablog/41147-Bob_Pease_died_in_a_car_accident_honor_him_Tuesday.php.  According to the obituary and other sources, Bob was on his way home from a celebration-of-life service for Jim when his '69 VW Beetle went off the road and crashed into a tree.  Bob's wife speculated that Bob might have had a stroke or heart attack.

Although Bob wrote his "Pease Porridge" column for Electronic Design magazine, he also worked as a reviewer for ED's arch competitor EDN.  Bob thoroughly reviewed the EDN Design Ideas submissions and added comments for the submitters.  Bob was a stickler for details and often sent back a Design Idea submission with more red-ink comments than black text on a page.  He went out of his way to ensure accuracy.

Bob also wrote about vehicles and accidents and mailed the EDN editors an annual "report" that listed the number of cars and trucks he saw (by make and model, if I recall correctly) and the observed problems.  Those problems included a lot of burned-out direction signals and brake lights, headlights, and so on.  Bob got in touch with as many of the owners as possible to alert them to the problem with their vehicle.

Bob also wrote a paperback book about driving, "How to Drive into Accidents - And How Not to," which is out of print but available from used-book sellers. Sad to say, a news report stated Bob did not have his seatbelt time on when his car crashed in a curve.

The world of electronics will greatly miss these two men.
 

Image courtesy of NXP.

To address this inefficiency, NXP has created the MPT612 integrated circuit that--along with analog-signal-conditioning circuits and a buck-boost regulator--can track the MPP and always draw power from a PV array under that condition. Thus a battery charger circuit with a MPT612 chip can maximize the power provided by a PV array at all times.

To help system and equipment designers get off to a quick start, NXP offers a reference design and a circuit board that implements it. The NXP application note, "AN10936:
Photovoltaic MPPT battery charge controller using the MPT612 IC reference board," provides specifications and the circuit diagrams for the board.  The MPT612 includes an ARM7TDMI-S 32-bit MCU core that can operate at up to 70 MHz.  Find the app note at: http://ics.nxp.com/support/documents/pdf/an10936.pdf. This information includes a bill of materials for the circuits.

According to NXP, the MPT612 comes "bundled with software libraries that implement the company's maximum power-point tracking (MPPT) algorithms, which are available for free and without royalty payments. Find information about the software-development kit, software libraries, and an application programming interface (API) at:  http://ics.nxp.com/support/design/microcontrollers/solar.mppt/.  The application doesn't include information about compatible compilers or integrated-development environments, so check with NXP before you buy software tools.  IAR Systems, for example, notes support for the MPT612 on its Web site. On the other hand, Keil, a division of ARM, does not indicate compiler compatibility as of early June 2011.

Distributors have small quantities of the reference-design board in stock with the part number OM13007.  Prices range from about $US 180 to $US 200.  The kit includes a JTAG adapter that links the board with a PC through what looks like a 9-pin serial-port connector. --Jon Titus

Although the sensor module uses light to charge the thin-film battery, you could also use the reference design with components that harvest energy from RF signals, vibrations, thermal sources, and other harvesting devices. The reference design includes wireless-network and USB software and a complete circuit design with RF layout, bill of materials, schematic diagrams and Gerber files.

The USB-stick wireless module uses a Silicon Labs’ Si4431 EZRadioPRO transceiver with an MCU that runs USB HID-class software and the EZMac wireless software stack. For more information, visit: www.silabs.com/products/wireless/EZRadioPRO/Pages/default.aspx and .

The Thinergy thin-film battery used in the energy harvesting reference design has a capacity of 0.7 mAh. Direct sunlight will completely recharge the battery in two hours. While the sensor-node MCU remains in sleep mode, the battery retains a charge for 7,000 hours (290 days). The wireless module can transmit continuously for about three hours, although it is designed to constantly recharge itself at an appropriate level to keep the thin-film battery from completely discharging. --Jon Titus
 

A big problem is this area involves covenants, conveyances, and restrictions (CC&Rs) that govern homeowners in many developments. Often these CC&Rs severely limit what homeowners can do on their property: no solar collectors, no antennas, no clotheslines, and so on.  In many cases, the most difficult aspect of setting up a PV system involves getting a homeowner's association and one's neighbors to permit it.

I could use a few small PV arrays to charge batteries for backup power. Our town has an active group of volunteers trained to provide many types of assistance, including radio communications nets, during an emergency so having local backup power for my amateur-radio transceivers would extend my operating time.  It's worth looking into. --Jon Titus

Texas Instruments has taken advantage of the FRAM capabilities in its new MSP430FR57xx family of microcontrollers that include 4, 8, or 16 kbytes of FRAM. According to TI's announcement, the MCUs can write data to FRAM more than 100 times faster that possible with flash memory and by using FRAM instead of flash memory or EEPROM, the new MCU family uses as little as 250 times less power. The MCU can operate with a clock frequency as high as 24 MHz and it consumes on average about 100 μA/MHz at 8 MHz. That power drops to 3 μA in a sleep mode that still powers the chip's real-time clock. The MCU's FRAM will retain data in all power modes. For more information about the MSP430FR57xx microcontrollers, visit: www.ti.com/fr57xx-pr-lp.

The FRAM gives programmers and engineers three other advantages. First, they can use the unified memory structure to change the partition between code and data sections of the FRAM memory. Second, unlike flash memories, the FRAM technology allows for single-bit programming, which can save time and energy. (The MSP430FR57xx MCUs include either 512 or 1024 bytes of SRAM.) Third, the new FRAM-based MCUs maintain code compatibility with other MSP430-family devices.

The new MSP430FR57xx MCU chips include a mix of 10-bit analog-to-digital converter inputs, comparators, general-purpose I/O connections, and serial I/O ports. Prices for the MSP430FR57xx microcontrollers start at $US 1.20 at 10K units, and samples and tools are immediately available. The MSP-EXP430FR5739 Experimenter's Kit costs $US $29 and can be ordered at www.ti.com/fr57xx-pr-ek-es and the MSP-TS430RHA40A Development Kit costs $US 99 and can be ordered at www.ti.com/fr57xx-pr-dk-es. TI also sells a package (MSP-FET430U40A, $US 149) that comprises a target board with a ZIF socket that accepts any MSP430FR57xx device in a 40-pin QFN package and a Flash Emulation Tool that connects the target board to a PC via USB.

You can find a good explanation of ferroelectric RAM at: http://en.wikipedia.org/wiki/Ferroelectric_RAM. Ramtron has a technical paper, "F-RAM Technology Brief," available at: http://www.ramtron.com/files/tech_papers/Ferro_Tech_Brief.pdf. --Jon Titus
 

Learn more about this demo board at: http://am.renesas.com/products/tools/introductory_evaluation_tools/renesas_demo_kits/yrdkrx62n/yrdkrx62n.jsp. --Jon Titus

 

Coincidentally, the people at SchmartBoard had just sent me a sample of an "SOIC-to-DIP" converter board that divides into three sections for 8-, 18-, and 28-pin sections for devices with a 1.27-mm pitch. The leads of the mounted IC then connect to pins spaced on 0.1-inch centers. You must solder the supplied pins in place, or you can use wires. A three-section board and header pins costs $US 5.00.

It took little time to solder the supplied header pins onto the 28-pin board and then solder an 'LVC4245 IC onto the SMT pads. This adapter will simplify the logic-level conversions needed for experiments and other lab work. The SchmartBoard products take a helpful approach to soldering SMT devices. They have recessed solder pads, so an IC easily slides into place as its leads align properly with the recessed solder areas. The LVC4245 has only 24 leads, so I soldered only 24 header pins on my adapter and left four contacts unconnected.

Instructions in each SchmartBoard package explain how to "mount" an IC and solder it with the solder already on the board. You need not add any extra solder, although I sometimes do. Your soldering iron should have a tip temperature of at least 750°F (400°C) and you should use flux. I recommend ChipQuik SMD291 no-clean paste flux.

The logic-level-conversion devices turned out well and I just ordered more of the SOIC-to-DIP adapter boards for my continuing work with lab experiments. This type of adapter also provides a great way to quickly prototype a circuit when you don't have time to create and order a custom-made board or when you don't have a PCB milling machine in your shop.

For information on the SchmartBoard/ez 1.27-mm-pitch SOIC to DIP adapter (part no.

204-0004-01) visit: http://www.schmartboard.com/index.asp?page=products_so&id=448.

For information on ChipQuik products, visit: http://www.chipquikinc.com/.

--Jon Titus

Microchip’s Bluetooth Evaluation Kit (part no. DM183036) costs $US 110 and it comes with the Bluetooth PICtail Plus Daughter Board, along with a 16-bit USB PIC24FJ256GB110 MCU and a 32-bit CAN/USB PIC32MX795F512L MCU plug-in module, both programmed with CandleDragon’s dotstack Bluetooth demonstration stack and SPP profile. You use this Bluetooth kit with Microchip’s Explorer 16 Development Board (part no. DM240001), available separately for $US 130.

The SPP profile requires about 3.5 kbytes of RAM and CandleDragon reports compatibility with Bluetooth chipsets from CSR, Broadcom, and Texas Instruments. The Microchip kit supplies a Roving Networks radio, so the dotstack software must operate with that radio, too. (Keep in mind that some Bluetooth radios include a stack and support several profiles, so they do not need an external stack on a host processor.)
Engineers and designers can download a free copy of the CandleDragon dotstack Bluetooth stack to use for evaluation and design work. For the software, visit: http://www.microchip.com/get/A0NT. When a design goes into production, the stack licensing fee starts at $US 4,250 for 5,000 units and goes to $US 13,950 for 100,000 units. For more information, visit: http://www.candledragon.com/.

For information about the Bluetooth SIG and available profiles, visit: http://www.bluetooth.com/. --Jon Titus

Voss has written an excellent book about the CAN.  It's easy to read, provides many helpful diagrams, and uses "bullet points" to call attention to key information.  Two icons--one a colonial bell ringer and the other a pointing finger--call attention to noteworthy information and emphasize important information.  I particularly liked the bus-timing diagrams that show activities down at the bit-by-bit level. This information makes the book particularly helpful when you must look at bus transactions with a CAN or logic analyzer.

Topics covered include: message frames, message broadcasting, bus arbitration, synchronization, error detection, faults, and physical-layer considerations.

I'll still keep my  files of CAN information, but Wilfried Voss' book will have a prominent place on the shelf above my desk.

Voss, Wilfried, "A Comprehensive Guide to Controller Area Network," 2nd edition, Copperhill Media Corp., Greenfield, MA, USA. www.copperhillmedia.com. ISBN: 978-0976511601.  --Jon Titus

Although Mike wrote this application for the Analog Devices ADuC706x microcontroller that uses an ARM7 core, it contains useful information about how to use platinum resistance temperature detectors (RTDs) and offers links to utilities and code available in a ZIP file at: http://www.analog.com/MicroConverter. The app note includes a lot of helpful discussions and equations. Because RTDs do not exhibit a linear change in resistance with respect to temperature, you must either linearize them with math operations or use a look-up table that related measured voltage (resistance) to temperature. A look-up table can consume memory, depending on the resolution you need, and math can chew up processor cycles, so you must decide on the technique best for your design.

Under the math heading, you'll get a better understanding of the direct-math method, a single linear-approximation method, and a piece-wise linear approximation method. So, if you plan to use an RTD. The ZIP file includes a RTD-coefficient-generator tool for Windows, the coefficient-software source code, and several C-language examples and subroutines for the ADuC706x MCU. But I bet you can apply the algorithms equally well to other MCUs.

This application note looks like a "keeper;" one you bookmark in your browser or print for a paper file. Anyone interested in RTD-based measurements should take a look. --Jon Titus

p.s. If you'd rather perform a linearization with hardware, check out the Texas Instruments XTR105 4-20 mA Current Transmitter with Sensor Excitation and Linearization. For a data sheet of this IC, originally manufactured by Burr Brown, visit: http://focus.ti.com/lit/ds/symlink/xtr105.pdf. Some time ago, TI acquired Burr Brown. --JT

If you wish, you can use both optocoupler elements in the small-outline SMT package for unidirectional signals and to perform logic-level "translations." Fairchild specifies the following timing information for this device: a 15 Mbit/sec data rate (non return to zero data), and a 60 nsec maxium propagation delay. Find a complete data sheet at: www.fairchildsemi.com/ds/FO/FOD8012.pdf.

I recently created a logic-level "converter" circuit that used an SN74LVC4245 octal bus transceiver, but I needed only two or three level conversions. It didn't occur to me to try an optocoupler as a way to convert 3.3-V signals to 5-V logic signals and vice versa. I'll ask Fairchild for a few samples to see how they work in this type of application. Price for 1000 ICs: $US 3.08 each. Fairchild quotes delivery of ICs in 8 to 10 weeks, but the company has samples available now. --Jon Titus

Each kit includes individual LEDs, 7-segment numeric displays, bar-graph LEDs, photocells, buzzers, resistors, capacitors, switches, pushbuttons, transistors, and a plug-in power supply.

You can find a grant application and more information such as Challenge Rules (legal stuff), Challenge Guidelines, and Project Submission Guidelines at: igen.eetimes.com/student-led-design-challenge.  You'll also find a tutorial about LEDs that explains how to control them, how to use transistors to turn LEDs on or off, and so on. A short video shows how to control many LEDs with only a few lines, and a link to the "What's a Microcontroller?" web site points you to more information if your team wants to use a microcontroller in its project.  Microcontroller use is optional.

Teachers who receive a grant and a parts kit will form a student team to work on an LED project, due on March 15th, 2011. That's the second phase of the competition--your team builds something interesting or useful with the components in the kit of parts. An LED team project might include a game, an aid for people with disabilities, a colorful and arty display, a score keeper for school teams, an alarm circuit, emergency lighting, lighting effects of model railroads or radio-controlled airplanes, and so on.  Teams can use their imagination.  (You don't submit the completed project, just a description and photos that show how it works.)

Awards for Phase-2 projects include a grand prize that takes the winning team's teacher to the San Jose, CA 2011 "Embedded Systems Conference" and honors the teacher and the project at the Ace Awards Ceremony (Tuesday, May 3, 2011).

The second-place team and honorable-mention teams will receive awards and grants for science, technology, engineering, and math equipment and materials.

If you know a student, middle-school or high-school teacher, let them know about this exciting kids-only competition.  Have fun! --Jon Titus