Simple Reversible Motor Control to Use with Arduino and Microcontroller

With these mods, this circuit will last quite a long time, especially if you make things easier for the relay by turning off power to the motor before switching directions. It is simple and effective by adding a diode reverse-biased across the coil just to keep the transistor from being fired when the coil is switched off.

The circuit is for a simple reversible motor control for use with the Arduino and other MCUs. It uses two TIP120 Darlington Transistors, two 220 ohm resistors and a 12 volt DPDT relay, parts easily obtainable at any Radio Shack. This design supports PWM for variable speed control, handles loads up to 5 amps, and is controlled using just two MCU pins for enable and direction.

It’s a nice little work around with few parts, but because the relay is mechanical there will be a short lifespan when compared to solid-state motor controller. It’s also worth mentioning that all of these parts can be purchased at your local Radio Shack when you don’t want to wait for component orders by mail. We certainly appreciate that it takes far few components.

Rest of the project