Adding Aftermarket interior sensor?

[lseguy]

Anyone had any success adding additional sensors to the factory alarm sensor? Idealy I'd like some sort of sensor that will definitely trigger the alarm when the glass is broken or when the car is actually touched if possible. Would like to be able to arm this sensor independently of the main alarm. All suggestions are welcomed. Thanks.

 

[joegr]

I haven't done this, so this is just theoretical advice. I think that it would work. Probably the best thing to do would be to wire it into the hood alarm switch.

 

[1LoudLS]

there are a few aftermarket alarm sensors that will send out a negative trigger when set off, but the harder part to getting it to work with the factory system is that all the factory triggers are normally closed circuits (meaning that the trigger wires have ground when everything is all sealed up, and an open circuit when a door, trunk or hood is open) which is the opposite of how aftermarket sensors work, you could use a relay toy reverse the sensors signal, but then you would have worry about too much power drain while the vehicle was setting since the relay would be energized most of the time.

 

[lseguy]

thanks. I may just go aftermarket alarm altogether. Had mine broken into IN MY DRIVEWAY not long ago. Not going to go into full details here on the web, but for now, I have the car temporarily connected into my house alarm system. The thieves didnt appear to complete their job, and it's always possible they will return.

 

[joegr]

there are a few aftermarket alarm sensors that will send out a negative trigger when set off, but the harder part to getting it to work with the factory system is that all the factory triggers are normally closed circuits (meaning that the trigger wires have ground when everything is all sealed up, and an open circuit when a door, trunk or hood is open) which is the opposite of how aftermarket sensors work, you could use a relay toy reverse the sensors signal, but then you would have worry about too much power drain while the vehicle was setting since the relay would be energized most of the time.

There are reasonable options.
1. Replace the hood switch with the NC alarm trigger - you lose hood protection.
2. Use a sensor with NO output and wire it to a relay with an NC set of contacts. Cut the wire from the hood switch and wire the NC contacts of the relay in series. This way, the relay in only engaged when there is an alarm event, so there is no current drain problem.
3. Build an electronic circuit to do the conversion.

 

[joegr]

thanks. I may just go aftermarket alarm altogether. Had mine broken into IN MY DRIVEWAY not long ago. Not going to go into full details here on the web, but for now, I have the car temporarily connected into my house alarm system. The thieves didnt appear to complete their job, and it's always possible they will return.

I'd get one of those low cost alarm camera systems with harddrive DVR and point one or two of the cameras at the car.

 

[1LoudLS]

There are reasonable options.

2. Use a sensor with NO output and wire it to a relay with an NC set of contacts. Cut the wire from the hood switch and wire the NC contacts of the relay in series. This way, the relay in only engaged when there is an alarm event, so there is no current drain problem.
3. Build an electronic circuit to do the conversion.

actually number two would probably work great, you could even use the relay in series with the hood pin as to not lose any coverage of the factory alarm.

i really dont see why this wouldn't be pretty easy to make happen.

 

[joegr]

... you could even use the relay in series with the hood pin as to not lose any coverage of the factory alarm.

i really dont see why this wouldn't be pretty easy to make happen.

That was my intent with option 2, but I can see that the part about cutting the wire would make it seem like I was saying to eliminate the hood sensor. I meant to say cut the wire and connect each of the cut sides to the relay contacts. Now, if the hood switch opens you get an alarm. If the relay engages, it's contacts open, so you also get an alarm.

 

[1LoudLS]

oh yea, sorry Joe

yea, wiring it up the way that joe said, these sensors will work


Glass break sensor
http://www.crutchfield.com/p_607506T/Install-Essentials-506T.html?tp=153&tab=detailed_info

hell you might be able to use a proximity sensor (alarm goes off if some one get close enough to the car, or sticks there hands through a rolled down window )
http://www.crutchfield.com/p_607508...08D-Double-Guard-Proximity-Sensor.html?tp=153