turn on dashcam when alarm goes off?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=136015
Printed Date: June 06, 2024 at 7:29 PM

Topic: turn on dashcam when alarm goes off?

Posted By: toxic0n
Subject: turn on dashcam when alarm goes off?
Date Posted: February 07, 2014 at 3:55 PM

Hi,
I have a 2 way Compustar alarm (Compustar 2w900fm) and recently picked up a nice little 1080p dash cam. I have it wired to a switched 12v source and it works great.
However, my car was hit and ran twice in the past 6 months. Luckily, a witness left a note the 2nd time and the offending driver had to pay.
Leaving my dashcam running with the car powered off will drain the car battery below 12V just after 2 days according to my calculations. Sometimes my car sit for 3 days at a time.

I'm trying to figure out how to make my dashcam turn on whenever my alarm is set off. I'm guessing I would need to wire up a relay to the alarm and have that turn on the camera, however I don't know where to start.

Any help would be appreciated. Cheers!

Replies:

Posted By: kreg357
Date Posted: February 07, 2014 at 5:30 PM

If you have a CM6000 brain, CN3 Pin 20 is a +12V Siren output. You could try that as the +12V power source for the camera. You
can program the CM6000 for siren output duration ( 30, 60 or 120 seconds ) with Menu 3-07. The only down-side is this wire also
goes to +12V briefly with a lock, unlock & start depending on Menu 3-09 programming. Additionally, if you have the OP-500
Programmer, you could reprogram an unused POC as a Type 20 - Siren2 output.

Not sure if a relay would be required, depends on the cameras current draw, but it wouldn't hurt. Here is the relay wiring :
Relay Pin 85 to Chassis Ground
Relay Pin 86 to CM6000 CN3 Pin 20 Brown wire
Relay Pin 87 to +12V with fuse appropriate for camera
Relay Pin 30 to camera + wire
Relay Pin 87a Not used

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Soldering is fun!

Posted By: toxic0n
Date Posted: February 07, 2014 at 5:35 PM

Thanks for the detailed and quick response!
I'll dig into the alarm manual to confirm the brain model and the output pins.
The reason I am asking about a relay, is that I also want the dashcam to run when the car is on when it powered by a switched +12v, not only when the alarm is on.
Does that change your answer? Also, is there a specific relay type I need to be looking for?

Posted By: kreg357
Date Posted: February 07, 2014 at 6:00 PM

The relay is a standard Bosch style 30/40 Amp SPDT relay. Use the relay and connect the switched +12V to Pin 30. Probably want to put a quenching diode across the relays coil. 1N4007 diode on Pins 85 to 86 with band towards Pin 86.

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Soldering is fun!