Car Door Ajar Sensor and LED Lighting

Hi there guys, I’m new to the forum and indeed Arduino itself! So please no hard feelings if I’ve posted this in the wrong thread or make some mistakes!

This is the first ever project I have attempted and need some help. Its nothing complicated at all compared to what I’ve been reading oh this thread! This is what I am trying to achieve:

So I’ve installed some custom led lighting in various areas in my car and am looking for them to come on when either any of the doors are opened or when any of the 2 switches are turned on. I am stuck in 2 areas:

  1. The coding
  2. The hardware

Which hardware should I be using? A transistor? To connect the 12V circuit. Also what is a permanent way of building my circuit than using a breadboard?

I have found the door “Ajar” sensor wire and when the doors are open there is 0.24V running through it and when they are closed there is the full 12V.

If possible I also want to know how to add a delay so they don’t just turn off as soon as the doors are shut - perhaps 5 seconds after and fade out?

Anyway, if I have forgotten something crucial do let me know and any help at all will be greatly appreciated. =D

Thanks, Cam

I would think an NPN transistor, 555 timer, couple of Rs & Cs, couple of screw terminals, some perfboard and soldering iron would get you there. All can be easily found at www.dipmicro.com
I can create a schematic once I get home after fencing class. Read the 555 datasheet in the meantime.

Anyway, if I have forgotten something crucial do let me know and any help at all will be greatly appreciated.

You forgot one thing. A door is a door and a jar is a jar ... so where's the logic in using a "Car Door Ajar Sensor"?