It must be time for robots to swarm. No sooner do I finish writing up James McLuckin's r-one swarm (see Robot Swarms For Students) and the Kilobots show up from Harvard University's. School of Engineering and Applied Sciences. The r-one will cost about $200 but the tiny Kilobot will be available from K-Team.The Kilobot uses about $15 in parts.
Of course, there is a bit of a difference between the two. The r-one has a 50MHz Texas Instruments Cortex-M3-based Stellaris microcontroller while the Kilobots are controlled by an 8-bit, 8MHz Atmel ATmega 328 microcontroller. The r-one is about the diameter of a DVD while the Kilobot is only 33mm in diameter, just larger than the small battery.
The Kilobot is actually a very elegant design. The two circular objects on the sides of the battery are actually vibrational motors with 256 power levels. The Kilobot sits on three fixed metal legs. The vibrations lift the legs and move the robot. It is not fast and it requires a flat, IR reflective surface like a table top but it works quite well. It is also very power efficient.
The ATmega 328 has 32 Kbytes of flash that is used a user program and the bootloader. The 1KB EEPROM stores calibration values for the motors as well as program data. The chip also has 2 Kbytes of SRAM.
Communication uses an IR transmitter and receiver on the bottom of the Kilobot. Communication between robots up to 7 cm apart is by reflection. Likewise, a master control board uses the same technique although it has multiple IR LEDs with a lot more power from a USB connection. The controller can program robots within 1 meter.
There is a multicolor LED mounted on the top. It has 3 brightness levels and can be flashed providing easy identification of each Kilobot. There is a debug port header on top as well but mass IR programming is how applications will likely be transmitted.
The rechargeable 3.7V Li-Pol battery provides about 3 months of autonomous operation in sleep mode. There is an optional 6V charging station that is essentially two metal plates attached to a power supply. The Kilobots have a built-in charger and one connection is through the legs. The addition of a metal clip on the top allows the robots to slide between the plates. Again, a very elegant and efficient approach.
Moving to a smaller platform would require micromachines that could be even cheaper but hard to build. I suspect that the Kilobots will be the smallest, inexpensive swarm solution for awhile. It will be interesting to see what kinds of competitions might come about. I have not doubt that the research aspects will be pursued extensively.
Besides, they are really neat.