This series of labs were a two-part process. First, we had to learn how to control a DC motor which uses a high current load.  Then, we used H-bridges to control the spin direction of the DC motor.

Transistor Lab

Using DC Motor with Arduino from cindy wong on Vimeo.

So how do you control a high-current DC load such as a DC motor? Transistors, in this case the  TP120 transistor which acts as an electrical switch between the Arduino and power to make the higher current load (in current, voltage)doesn’t overwhelm it. In this scenario, I used a potentiometer to control the spin intensity of the DC Motor. FYI, I learned that soldering a DC motor is easy since the order of the wires, power or ground, doesn’t matter! Check out the video above.

Update: Note that clickety, jerky motion of the DC motor above? Apparently, that is the result of the DC motor receiving too much power. Looks like that DC Motor is meant to run between 3-5V power. The Arduino is blinking (resetting itself) each time as an indicator for us (according to Igoe).

Here’s the Breadboard setup.

DC Motor Control Lab

H-Bridge to control DC Motor Spin on Arduino from cindy wong on Vimeo.

To change the direction of the DC Motor’s spin, you’ll need an H-bridge which connects to your breadboard. The H-bridge is handy when you want to control multiple motors. In this case, we’re controlling the circuitry by alternating power between the H-bridge’s motor logic pins which are connected to digital pins on the Arduino. Sending power HIGH or LOW changes the motor’s spin direction from one way to the other. See the bread board below.