Automatic DLR with chasing lights

For some time I wanted to put LED DRL (Day Running Lights) on my car.
It was some pain in the a*** to run the wires into the car and I was looking for a simple and elegant solution.
And I was hit by inspiration!

I found the solution!
A DRL which power ON at the engine start and goes OFF a few minutes after the engine is stopped!
But how?

Simple, with an Arduino we test the battery voltage and decide to go ON or OFF because the lead-acid car battery goes under 12.8 V when the engine is stopped and above 13.4 when the engine is running!

Here is the code: