Step 1: How Does It Work?
During the second step the motor turns left.
So if I insert a switch I can turn the motor to rotate right or left.
Step 2: Some Calculations ...
I want to understand what happens so I started to calculate the paralell resistors value. You may find here a paralell resistor value calculator.
I tried with resistors 3R - 10R - 33R - 62R. They all worked but resistors lower than < 62R were warmed.
With 100R resistor it doesn't work.
The R3 resistance of the motor is 12R. So total I had 12R (motor) + 62R resistor = 74R.
Rtotal = (R2 + R3) * R1 / (R2 + R3) + R1 = (62 + 12)*62 / (62 + 12)+62 = 33.7
Step 3: The Polarity Switch
Don't you know what xanax is?
It is a sleeping pill "developed" by the old man from Emir Kusturica's movie Promise Me This. Here is a sample on youtube.