Tag Archives: Remote Car Starter

Build your own remote car starter with Bluetooth

With wintry weather approaching, create your own remote start unit for your car using Arduino and Bluetooth.

Remote door locks are pretty standard nowadays, but chances are you don’t have a remote start unit for your car. You could always just buy one and install it, but if you’re (former) Subaru Forester owner Chris Johnson, you would instead design your own using an ATmega328 chip and a Bluetooth module.


His control box, seen as a prototype in the video below, uses a computer to connect to the in-car module and start the vehicle via several relays. It takes into account whether the car is in gear and if it’s running during this sequence. It shuts off when driving, or after 30 minutes. Physically, the starter (now fully inside the black box) connects to the car via a DB-9 connector, so removal for reprogramming was quite easy.

Johnson was able to get information on the engine control module (ECM) via the car’s maintenance manual, but verified these values using an oscilloscope. Of this process, he notes that, “You probably would have enjoyed watching me trying to read the waveform period on the oscilloscope as I drove around the parking lot.”

As with most projects on this site, if you want to try it yourself, proceed at your own risk. Control of a heavy and, though we don’t always think about it, extremely fast object is a serious responsibility. Also, though certainly entertaining, it’s probably best not to ‘scope and drive — get someone to help you! As the wicked wintry weather approaches, be sure to check out the remote starter in more detail here.