Circuit to control 12V LED strip with Arduino

The Arduino board I am using to control the strobing effect of the turntables is an Arduino Due which has a max output voltage of 3.3V. This falls rather short of the 12V LED strips I bought to light each turntable.

After doing some research, I found that the best approach is to power the lights using an external power source which runs at 12V and connect it to and NPN transistor. In layman’s terms (ie. my only understanding), the Arduino sends a signal to the transistor which tells it to open, allowing the full voltage to run through to the lights. The best part about this setup is that the code is exactly the same as if I were programming individual LEDs, because the same commands you would write to light up an LED is used to open and close the transistor.

So I took a trip out to JayCar, bought a couple of TIP122 transistors and built the new circuit.

Here’s a short video of the transistor working it’s magic.