I'm building robots. I learned about "beambots" from Make Magazine, got some parts from Solarbotics, and pulled out all my disused electronics equipment from my garage. Amongst the fine bits and pieces, I got the Junkbots book by David Hrynkiw and Mark Tilden, which has a instructions for a lot of fine beambots.
June 2006
This robot charges up some capacitors from a solar cell, then drives the motor when it's charged up enough, making it spin around a little. In full sun, mine has about a two second loop between charges.
I built this following the instructions in the Make Magazine 06 Beambots article. For parts, I ordered the parts bundle from Solarbotics.
June 2006
This little robot tries to drive towards the light, and will back up when it runs into something, or tries to drive off the table.
For this, I used the instructions in the Junkbots book. The control logic is based on the "herbie" LM386 audio amplifier design, and includes a switch in the front to switch directions when it runs into something. I made one modification, that you can see if you look closely at the picture, which is a switch that presses on the floor as it drives. When the switch opens up (when the robot tries to drive off the table), it activates the backup circuit.
The don't-drive-off-the-table feature was the most complicated part of the whole thing. Easy to wire up, but the switch is fairly sensitive to motion. When switching from reverse to forwards, it kicked the whole robot with enough momentum to flip the backup switch again, causing it to back up again. Eventually, it would back itself of the other side of the table! My workaround was simply to add more weight to the front of the robot.
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