Quick'n'easy Light-sensitive Bristlebot-mod

What's a bristlebot? It's a vibrating robot based on a toothbrush. It uses a motor with an unbalanced weight (like pager motors) which causes the entire thing to skitter across a surface. Originally based on vibrobot, the toothbrush version (bristlebot) was made by the awesome folks at Evil Mad Scientist Laboratories. You just need a toothbrush, motor, and battery.
 

We've built a couple of these and they are delightful to watch. However, we wanted a little bit more interactivity so it would react to something in the environment. Hence bristlebot-mod

 

The learning sensor is awesome because you can quickly calibrate it for different light levels. You can make your bristlebot-mod run in the dark, or run in the light. You can also make it run only in the right temperature, or when it gets loud, or something with the appropriate sensor.

Check out Iwasaki-san's bristlebot-mod-mod He uses a transistor to amplify the vibrations.

- a toothbrush with uniformly angled bristles

- a vibrating motor, from a place like Sparkfun

- learning sensor, from Aniomagic

- a rectifier diode

- large battery

- some double-sided adhesive

 
Of course you could use a transistor, light sensor, and a few resistors, but you can't beat the simplicity of using a learning sensor, plus  the fact that you can easily calibrate it on the fly.

This is the basic layout of the electrical connections:

 

- hookup the motor to the + and H holes

- hookup the diode. Make sure the dark band connects to +

- connect the battery

 

A motor turns because of the magnetic field built up in its coils. When the motor is turned off, the magnetic field collapses. As the field collapses, it generates an opposite current that may damage your learning sensor. The diode is needed so it can safely conduct this opposite current, while allowing normal current to power the motor.

 

Next, attach the diode. Make sure the dark band (cathode) is connected to +, and the other end (anode) is connected to the H hole.

 

Keep the + pin long; it's stiff enough so you can bend it to make contact with the batter +. Clip the H pin short. Solder both pins to the holes.

Finally, now attach the motor wires to the diodes's pins. Unless your motor specifies it, it doesn't matter which wire is connected to which pin.

Now, attach a thin wire to the - hole. Strip the end and make a small coil that will connect to the battery -.

 

With double sided adhesive, attach learning sensor, motor and battery to the toothbrush head.

 

Bend the + pin to make contact with the battery.

 

Experiment with calibrating it in light and dark situations. Calibration happens when you connect the C hole to the - hole, as shown in the video. If calibrated in the dark, it runs only when you shine light on it. If, instead it's calibrated in the light, it runs in the dark.