This is what I did to power the Arduino which I used in my engine start button project. It’s a simple and cheap way to power an Arduino in a car. This will requires some basic soldering skills.

Step 1

But a simple USB charger – the kind that plugs into your car’s power outlet. They usually cost ~$2-5(USD). You can probably find them at most convenience stores, or maybe a box store of your choice.

USB car charger – As you can see, the output of this USB charger is rated DC 5 volts and 1 ampere.

The USB charger covered here is a 1 amp charger. This should work just fine, but a 2 amp one may be more preferable.

This charger came apart real easily. Just unscrew the end that goes into the car’s power outlet, and the thing basically falls apart!

USB car charger disassembly — Remove this end

USB car charger disassembled — You should find something like this inside

Step 2

Decide whether to keep the USB port on the circuit board or if you’d rather remove it. I removed it from mine. If you decide to keep it and power the Arduino via USB cable, then skip to step 3.

Removing the USB port from the circuit board

To remove the USB port, use a soldering iron and some solder wick to absorb the solder on the pins that are holding the USB port in place. After this, the USB port should come off easily. You may need to heat each individual pin in sequence, back and forth, while pulling gently on the USB port.

When finished, it should have come apart something like this:

Step 3

We need to solder the wires onto the circuit board for the input and output power.

USB car charger pins — Where to solder the wires

USB car charger wires — Wire soldering points

USB car charger modified — The finished product

Now you can put the circuit board back into it’s original case, and have a set of wires hanging one on either end. This power supply is small enough to tuck away almost anywhere! Just make sure it can ‘breathe’.

I hope you found this tutorial helpful! Leave a comment if you have any suggestions.