If all went well, Mousey the Junkbot's behavior will be apparent once you flip its tail. The robot should zoom away and eventually hone in on the brightest area in the room. It works best if you limit Mousey's surroundings to just one source of illumination − one light or sun-soaked window. Here are some other fun experiments:
Put Mousey in the hallway and close all doors except one. Make the open room as bright as possible, and see if Mousey eventually scuttles in there. Try orienting Mousey in different starting positions.
Tune Mousey's light sensitivity by bending the eyestalks. Move the stalks farther apart, closer together, and bent in different directions until you get the steering you’re looking for.
Use a flashlight to lure Mousey around. This will drive pets insane! But be careful; agitated pets will attack your robot and try to rip its components out.
If you turn on Mousey and nothing happens (cue laughing clarinet, “Wha-wha-WHAAAA”), or if it acts strangely, turn it off immediately. Something went wrong with the build. Here are a few things to check:
First, ask yourself the tech-support alpha question: is it plugged in? Make sure that the battery is new, the battery snap is well-seated, and its positive and negative wires are properly connected. Then make sure that bare wires, pins, and solder joints are not making unauthorized contact with one another. One sign that you may have such a short circuit is if the battery gets warm.
Next, double-check all solder connections against the instructions. Besides being in the right places, they should all be fat, shiny, healthy-looking joins. Use the multimeter to check resistances, and resolder anything suspicious.
If Mousey frantically spins in a tight circle, you've probably hooked the motors up incorrectly. Reverse
the wires that connect to the motor on the side that's going backwards.
If it's a broader circle, the motors might be wired correctly, but just not level with each other. If so, reglue the motors so they're symmetrical and make sure the tires are the same size.
If Mousey's always heading backwards, swap the wiring on both motors.
RESOURCES
This project is adapted from my book Absolute Beginner’s Guide to Building Robots. You can find schematics and installation instructions for additional Mousey hacks on my robot page at Street Tech, streettech.com/robotbook. More cool hardware hacks live in Dave Hrynkiw’s Junkbots, Bugbots & Bots on Wheels.
To find other ideas for hacking your Mousey, and other LM386-based bots, Google “robot +LM386,” “herbie +LM386,” and “Randy Sargent +robot.”
To learn more about DC motors, and see a dissected version of the motor used in this project, see http://xrl.us/fkxh.
References:
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