Cheap Easy Solar Powered Robot  Make a very cheap, relatively
easy to construct robot which will wake up any time you shine a
desk lamp on it. There are no sensors on it, although I suppose
the solar panel can be called a sensor. I plan on adding solar
panels and another motor, and making it controlled by a PIC
microcontroller in the future.  Remove these adsRemove these ads
by Signing Up  Step 1: The Circuit  The circuit for the robot is
very simple, it has no digital electronics. It's called a
'miller solar engine' ( and it allows a small solar panel to
power a motor.  The solar panel stores energy over time by
charging the capacitor in the circuit.  When enough energy is
stored (this is sensed by the '1381' part) the energy is allowed
to flow through the motor and the robot moves.  Then the whole
process repeats.  In the circuit diagram, C1 is a capacitor, D1
is a diode, R1 is a resistor, and the circled M is the motor.
If you buy from, here are the part numbers for 1381 chips (they
'turn on'/'become act