Sun Mirror       

Sun mirror is a solar powered artbot that uses a popular circuit called a "Solar Engine".  The circuit only uses two transistors, one flashing led, one resistor, one capacitor.  Start by connecting your parts on a protoboard to be sure all the parts work together.  Fixing a non-working circuit after building it will make a mess of things.  Besides it's fun to try different values of capacitors and resistors to see what happens. Your finished circuit can be built on perfboard. This circuit will allow some changes in component values.  I used 2N4401 and 2N4403 transistors because that's all I had. The finished artbot was placed in a glass canning jar.  I made a clear view top for the solar cell instead of using the metal canning jar lid.  Notice on the schematic I added a diode across the motor to prevent any "kickback voltages" that can damage transistors.

Circuit tested on a protoboard

Working circuit made into a artbot.

Construction using "Freeform style":
I used a "PCB" business card as a base.
The tiny piece of perfboard above the blue capacitor is the circuit.

Thin aluminized mylar "mirrors" are super glued to motor end.
The motor is held by a plastic cap plug on a spacer.

Capacitor held down with wire soldered to the PCB card.  Circuit held by wires to the capacitor.

Make a holder for the solar cell out of clear packaging plastic.  This will take the place of the metal top that comes with the canning jar.

Cut a second circle and sandwich the solar cell between them.

Place your artbot in a jar.  This will protect your Solar Engine from dust and little fingers.  Next place it in the window and feed it lots of photons.

A different artbot that uses a pager motor, capacitor on bottom shelf.
The top and bottom sections are connected with velcro and come apart. 
Electrical connection is through a Molex connector seen just under the top solar cell.

  My collection soaking up the morning sun.

PDF of the circuit

Youtube movie

Back to other artbots