Currently they cost about US$24 each but can be had much cheaper if ordered in volumes. They are fairly simplistic, light and are able to auto charge easily. Here is a list of the hardware involved into each current version of the Formica swarm robot:
- Drive: Two coreless DC motors, 4mm diameter, as used in mobile phone vibrators. Direct drive via 3.5mm neoprene wheels friction-fit on shafts. Differential steering.
- Battery: 320mAh lithium polymer. This is sufficient for 1.5 to 2 hours of continuous, autonomous movement.
- On board charge regulator and copper terminals/ground skis enable robots to self-charge from a simple "bay".
- Micro controller: MSP430F2254; 16kB of flash program memory, 512 bytes of RAM.
- Communications: Three IR LED/Photo diode photo transistors with multi-frequency FSK modem scheme. Range >50mm, variable with lighting conditions.
- Sensors: down-looking IR photo reflective sensor measures floor reflectivity. May be used for "food" detection of reflective objects. IR communication receiver photo transistors double as light sensors, enabling light-seeking behavior, etc.
- Display: Bi-colour LED enables red/green/yellow behavioral "mood" status output.
The hardware (schematics, PCB layouts, etc.) and software (firmware, code, etc.) design is available for all to download and use. So make sure not to step on these little friends the next time you see them moving around your floor! Here is a short video to see them in action. Enjoy.