I am installing a video camera (Watchguard) in a police car and I am needing a 12 volt (+) input off the siren speaker for a siren sensor. The speaker output wires show a 35 volt AC current. Any ideas how to apply a relay to the 35 volts AC so I can get a 12 volt (+) feed to one of the sensors in the camera. I am trying not to have to go inside the siren controler itself to get a 12 volt (+) feed when the siren is activated.
Thanks for any help.
Bobby
leeso20@wmconnect.com
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kc5niy
I have the answer in my notes some where. I have had to do that a few times. I'll be back.
R1 and R2 drop the input voltage since the regulators max is 35.
D1 stops the sirens negative phase from bleeding C1
C1 keeps the regulator alive during the negative phase. You made need to adjust it up to maintain a flat output.
U1 is a standard 12 volt linear regulator
Thanks for the diagram. I am getting the stuff together now.
B. Bean
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kc5niy
MaximaLover wrote:
Wouldn't you want it to turn on with the lights instead of the siren?
Agreed. Sirens are turned off when on-scene, so your camera would stop gathering evidence when the officer pulled over. As the siren is not blaring when the drunk stumbles over himself, that evidence will not be gathered.
maxima lover wrote:
Wouldn't you want it to turn on with the lights instead of the siren?
All of them do turn on with the lights.
The siren feed is most often used to put an icon on screen to indicate that the siren was active. Its a liability thing in case the cop t-bones someone going through intersection and the other driver claims did not here him coming. Or when a driver claims he didnt pull over becouse he didnt here the cop.
firstrax wrote:
maxima lover wrote:
Wouldn't you want it to turn on with the lights instead of the siren?
All of them do turn on with the lights.
The siren feed is most often used to put an icon on screen to indicate that the siren was active. Its a liability thing in case the cop t-bones someone going through intersection and the other driver claims did not here him coming. Or when a driver claims he didnt pull over becouse he didnt here the cop.
I was wondering if that's what it was for, but I don't think I have ever seen one that showed that the siren was active because it can be heard through the camera's mic. I guess if this one didn't have sound, it would be needed.
maxima lover wrote:
I was wondering if that's what it was for, but I don't think I have ever seen one that showed that the siren was active because it can be heard through the camera's mic. I guess if this one didn't have sound, it would be needed.
The siren feature is rarely hooked up for the reason you stated and because its a major pain. Out of 8000 vehicles I've only done about 10 with siren.
Most video camera systems have a siren interface option board. It taps in to the siren speaker wire with a small transistor and sends a signal back to a sensing wire in the camera system harness. This usually records a "S" on the display to show the siren was sounding at that time.
John Liguori
Emergency Vehicle Technician
Major Automotive
Kenvil, NJ
www.spectrum2way.com