The GRASP Laboratory at the University of Pennsylvania has an interesting robotics program that deserves some attention. GRASP stands for general robotics, automation, sensing and perception, and the lab blends computer science, electrical engineering and mechanical engineering in a collaborative environment that lets students, research staff, and faculty work together on interesting projects. According to the lab's information, it has a $10 million budget that helps researchers build autonomous vehicles and robots, develop self-configuring humanoids, and create robot "swarms."

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.