Hi everyone. I have a quick question. I`m trying to devise a circuit that works off my car locks. Basically they get a negative pulse, which starts a latched relay, which will power up the ACC line going to the startup/shutdown controller. I`ve included a picture of my current circuit but I`ve noticed one problem. In order to stop the chained relay (stuck-on) action you
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need to kill the 12volts going to it. So, I have it rigged to pin1 of the parallel por, t though a molex conntor would work two. Here`s the issue: The moment the PC turns on the ACC line turns back off. This in turn tells the controller to shut down. Hmmph. I was wondering if I throw it on pin 2 or 3, and have a program that waits oh. 2 minutes, then turns ON the pin, if it`ll work. Only problem is that start-up sequence tends to be a bit of a pain, and flashes the pins. Any ideas Many of us do something like this, but with the ACC turning it on. If your door unlock is long enough to get the PC to output 12V, it will hold the relay closed until it shuts off. Just make sure the diodes are in the right direction and it will be safe. They can be small 1/2 amp generic ones. That makes sense, but I just redesigned the circuit while I walked the dog. BTW: What relays are you using You have two relays hooked up in series there, and it seems to me 12v wouldnt do it. Unless there 5v relays Replace the bottom relay/ parallel port bit with a relay that has a N. C. position. When it`s N. C. the rest of the circuit gets 12V. Have the relay hooked to the ACC line, so when the ACC goes on, the circuit loses 12V. Have the circuit`s output and the ACC line hooked together with a few diodes. Voila. Oh, BTW, about the locks being long enough. I`m just adding electric locks now. It`s a set of 4, and I only have two doors I can hook it up to in...
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