Meeting Minutes 2009.02.12

SWARM notes 2/12/09

Platform Discussion

Different wheel configurations/arrangements diagrammed on the whiteboard, photographed by Dillo.

Design constraints:

Accessible Open Extensible Inexpensive May be used for Tesselation plan next year

Motors

Power window motor/windshield wiper/Van door motor Wheelchair motor Brushless cordless electric drill

Wheels and casters

Wheels pretty much is the option. Legs are too complex and don't meet design criteria. Tank treads are hard to build, difficult to maintain.

Wheel Size?

Needs experimentation Children's bike/tricycle Bigwheels Radio flyer Wagon

Sensors

Ultrasonic range sensor

Reviewing previous discussion: - Central poller - Everyone listens and reports the time of each poll response - reported time allows triangulation.

Ultrasonic because: - You can blast it without killing people - Smaller speakers - Won't be as susceptible to interference than sonic

Range: Reflection-based sensors would necessarily have shorter range than this.

dead reckoning

This and Ultrasonic could drive hexes - Optic encoders to figure out distance travelled - Hacking laser mice?

I2C links Multiplex multiple devices on a bus, 1 master, many slaves - can run up to 128 devices - Range unknown: at least as long as a monitor cable - Increased noise sensitivity. But since it's clocked, we can ratchet the clock speed down to accomodate this problem. - Built into arduino

GPS, Zigbee, Aggregator(SPU) 3 I2C chips on bus. Each sits on the bus and talks to it's piece.

- Alternative strategy: RS485 multidrop bus Potential issue: bandwidth.

I2C is full duplex (RS485 is 1/2)