Re: a creative way to make an automotive security kill switc
Hi,
You'll be surprised at how many security systems have a flashy keypad, with a million combinations but just have two wires going to the 'hidden relay'. Including some car imobilisers. Anyone with a screwdriver could break in, its like putting a $10000 security system on a shed door
I'm no expert, but just have two micros. One reads the keypad (inside the external keypad module) and gets the users code, then encrypts it (simple look-up table) and send it via RS232 to a micro next to the 'hidden relay'. The micro at the relay, reads in the data, decrypts (LUT again) and if the code is correct, activates/deactivates the relay.
That way, 'crossing/cutting' wires won't do anything, except tell the relay micro that something is wrong (starts a tamper alarm). And you could have a '3 strikes and out' thing with the codes. It beautifully simple, and pretty secure. Unless a 'theif' happens to be carrying a laptop, microcontroller reader, disassembler, and have hours to get access to the pins on the relay micro - Are theives this good?
You probably won't even need encryption, but I've just been reading up on it
Anyway, sorry if this is a bit 'left-field' but I did this as a project when I first started with micro's.
Good luck,
BuriedCode.