12volt

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=5531
Printed Date: June 27, 2025 at 12:39 PM

Topic: 12volt

Posted By: tikech
Subject: 12volt
Date Posted: November 16, 2002 at 10:08 PM

Here's what I would like to do, if you can help that would be great. When I disarm my car alarm I would like the headlights and backup lights to come on, that’s the easy part I know how to wire the relays. Here is the hard part. I only want this to happen when it is dark out so I want to use a photo sensor to power one side on the coil only when it is dark. I would ground the other side of the coil from my dome light relay in the alarm. So, in theory when ever I disarmed the alarm it would ground the coil of that relay, but the relay would only have power when dark by means of the photo sensor. Then I would wire the relays to power the headlights and backup lights.

Any help any one could give on the best way to do this would be great. I am not sure on what all I would need to do this, just a photo sensor, what else?

Replies:

Posted By: the12volt
Date Posted: November 17, 2002 at 5:48 PM

I did some searching and found a few links that you'll probably find helpful......

https://www.aaroncake.net/circuits/hdlights.htm
https://www.aaroncake.net/circuits/lightdrk.htm
https://www.mtnmicro.com/catalog/picturecatalog/zdaynight.html
https://www.uoguelph.ca/~antoon/circ/actrelay.htm
https://www.uoguelph.ca/~antoon/circ/sensor4.htm
https://encyclobeamia.solarbotics.net/articles/photodiode.html

Posted By: the12volt
Date Posted: November 17, 2002 at 6:51 PM

Here's a kit you can order for $7.95 https://www.rainbowkits.com/kits/lg-2p.html

Posted By: tikech
Date Posted: November 20, 2002 at 12:31 AM

Thanks alot. All the info has been very helpfull.