I live in a neighborhood that some people are scared of, and I drive an old car that is very easy to break into and steal. I didn't want to put an actual car alarm in my car because of the cost and their proclivity for false alarms. So, I decided to make a fake alarm for my car with a flashing red LED while installing my car stereo.
Warning: Do not attempt this instructable without assistance if you have no knowledge of wiring. Doing so can result in serious damage to you and your vehicle. You will also need to drill at least one hole somewhere in you dash. If you don't feel that you can do this without damaging the internal workings, then don't try this. If you have a newer car with anti-theft features I also advise you not to try this as screwing with the wiring of your car may trigger them and render your car or it's stereo useless.
Step 1: Supplies
1. Linrose B5100H1FL Panel Mount Flashing LED, Red, 20mA, 12v $3.50
Can be obtained via Fry's Electronics:
(Any flashing LED that works on 12 volt DC power will do.)
2. Wire tool for stripping and crimping connections. Approx. $3 to $5
These can often be obtained with the connectors
3. Red wire crimp connectors
4. Access to hot and ground wires that are not controlled by your ignition switch
5. Extra wire
5. 12 volt toggle switch (optional)
7. A drill and drill bits
You really should already have these. If not I advise you to seek assistance before attempting this instructable.