Step 11: TIP120 & DC Motor
For the hula hoop to move, we want to use a DC motor to push up the pipecleaners enough to provide a small jiggle.
For this purpose, we only need to control the motor in one direction, so we can use a TIP 120 to switch the voltage.
DC motors are noisy and need filtering. This is why we use a 100uF capacitor across the power supply. We use smaller 0.1uF ceramic capacitors near the motor to filter out sharp spikes.
Although the TIP120 has an internal diode across the base and emitter, using another diode for our specific rating is always a good idea to prevent against back EMF.
On the proto-screwshield we use a screw terminal to attach the leads of the motor. Alternatively, you can solder them on.
You will want to test how everything behaves and modify the circuit accordingly for your motor.