LC
The Line Chaser

LC (Elsie) is a small multi-purpose mobile robot platform. She is about 7" tall, 8.5" in diameter, and weighs about 2.5 lb. In her fire fighting gear she is about 12" tall, 9.5" in diameter, and weighs about 5 lb. She is more compact, more durable, easier to handle, and more versatile than my other bots. I used lots of wing-nuts and rubber bands, so it is easy to open up for repairs or modifications.

Originally conceived as just a line follower (hence the name). By the time I started building her, the design was much more general-purpose. I have used LC for an assortment of robot sensor, and behavior experiments. LC has competed in many contests including the Trinity Collage Fire Fighting Home Robot Contest.

LC with her skirt off.

LC in her fire fighting gear, with some of her awards.

What is she made of?

The chassis is a piece of thin plywood.
The body-shell/bump-skirt is a polyethylene bucket.
The computer is a Motorola 68hc11, on a BotBoard 2 circuit board. The BotBoard 2 has 32k ram, and a large prototyping area, so I could fit all of the extra input-output, and motor control circuitry on one board.
Driven by two Tamiya "High Power" gear motors, with model airplane wheels.
Powered by a 7.2 volt NiCd battery pack.
And a bunch of nuts, bolts, switches, connectors, LED's, ...

Sensors

Each motor has a phase-quadrature incremental encoder, so the motors can be accurately speed controlled, and the bot has a good sense of distance.
The body-shell has four switches under it and acts as an all over bump detector so it will know if it runs into anything.
She has an infrared proximity detector attachment, so she can wander around without bumping into things.
There is a special two switch front bumper attachment for finding its way through the grand maze.
There is an eight element line detector attachment for line follower contests.

Fire Fighting Hardware

An expansion board providing 32 analog inputs and 10 discrete outputs.
Three active infrared range finders of my own design. One looking to the left, one looking to the right, one looking straight ahead. Accurate to about 1/4", maximum range of about 8".
Two passive candle detectors, providing crude stereo vision. Each has eight phototransistors.
The blower out of a hair dryer, to put out the candle.

Competition History

Robothon, Seattle Robotics Society

1997	First Place, Second Place,	Grand Maze. Line Following.
1999	First place, Second Place, Third Place,	Fire Fighting. Grand Maze. Line Following.
2001	First place,	Fire Fighting.

North West Regional Fire Fighting Home Robot Contest