Step 1: Parts needed
2 DC motors
2 round mirrors
something to mount mirros on to the motor rotor. (a gear head will help)
Power to run the motors 6V AC to DC convertor
Step 2: Making the connections
The attached picture shows how it has been connected. The digram shows how the wiring was done. Speed control was done with PWM via Arduino.
One motor runs at a constant speed of PWM value of 32 and the other ones speed can be increased or decreased via two push buttons.
When both motors run at same speed a constant ellipse is displayed.
Step 3: Connections and code
Alignment is very important for this to work but a little bit here and there will do
The laser is focused on the motors mirror running with constant speed. This displays a circle on the wall. Now place the second motor in such a way that the LASER bouncing from the first mirror falls totally on the second one. The mirrors have to be very close for this to work.
Switches are to be connected to the Arduino input pins 1 and 2.
A variable stores the value of the PWM for second motor and the pressing of the buttons brings the state to LOW. And when ever this happens the factor is incremented or decremented as per the switch being pressed.
Now connect the wires connect the Arduino the USB and upload the code.