Blinking red light

P

PhreakPhy

Limp Gawd
Joined
Feb 2, 2003
Messages
357
I realize that this is of topic, but i figuret that the moders would be able to help me out.

I am trying to make a fake alarm, with a blinking red LED. But I dont exactly know how to wire my relay. It is RadioShack #275-249.
I would draw a schematic, but i dont exactly know how to do it, and make it understandable. It dose have a picture on the back, but i allready tryed what i thought would work, with noi sucess. any help wiriing this realy wold be apriciated.
Also, how do I calculate what size resistor to use?
 
well the relay is just part of the stuff. I have a blinking led, but i want it set up to a normalu closed relay so that it wil only come on when the car is turned off.
 
ditch the relay find the right resister connect to fuse box done. Leds will not kill a car battery unless you do'nt drive the car for >5 years which by then the battery will be dead by other mean any way
 
so what size resistor do i need to get 12v down to 5v? And how is this calculated?
 
Blinking LEDs

As for the ignition thing, you want to hook 12v to the COM input of the relay. The LED connects to the NC lead. Your ignition tap (easiest to jump from the fuse panel) feed the coil of the relay. This way when the key is off, the relay switches back to its normal state and the blinking LED starts its thing
 
Originally posted by mattg2k4
This tells you what you need to know. Also, don't double post this.
Click to expand...
I also found this site (I think this is the url) and it probably tells you what you need to know.
 
I was finaly able to remember ohms law today, well i asked a teacher. Thanks PS-RagE for the info on wiring the relay, i got it workin great, and I would have never figured that one out on my own, well maby i would have, there are only so many connections to make, i would bet it right eventualy. But with the DPDT that i have it would have aken twice as long. Thanks again.
 
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