# backup alarm cancel



## dodgefan99 (Nov 16, 2011)

I am wiring a back up alarm into my reverse lights and was wondering how or if I would be able to use a momentary switch to cancel it when I am backing up if need be.


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## greg8872 (Jan 17, 2007)

You can do it with two items from Radio Shack

1. Push Button (Normally Open [NO]

2. 12v Relay SPDT (DPDT will work too, just only need one side) Make sure it can handle current of backup alarm,

Run a lead from a 12v source in the cab to the push button. (safe side, fuse it too in case wire rubs and shorts along truck body). From Button run the wire to the relay, tie it to BOTH one side of the coil and the Normally Open (NO) lead for the relay. Run the Normally Closed (NC) lead to the Positive lead for backup alarm. Ground the other side of the coil. Then for the last lead on the relay, run that to 12V from your backup lights

I drew the attached drawing (pretty rough I know) to have the relay at the back of the truck (less of a "custom wire run" that will be hot more often). Just make sure you seal it up well. Alternative is to put the relay in the cab and then the lead from the cab would just to to +12v on backup alarm.

This setup makes it so when you push the button, the relay will trip, killing the backup alarm, but then also powering itself, so you don' thave to keep pushing the button. Will stay this way until Backup lights go off.

-Greg


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## dodgefan99 (Nov 16, 2011)

Let me give a little bit of back story...

What I currently have is a full bar on my roof that is running to a whelen cencom gold control head that I picked up off of ebay. I was looking to cancel the backup alarm through the cencom unit. It can be programmed to be either a on/off or a momentary. 

What I was looking for is pretty much what I was looking for. The only other thing I was wondering was do I have to trun the switch off in order to use the backup alarm when I move to another place. Ie....Back up, kill alarm, place in drive, then back up with alarm.

I want it to latch for the duration that I am in reverse but possibly revert back normal without any of my guys having to turn the switch off, they will forget it.


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## greg8872 (Jan 17, 2007)

The method in my horrible diagram (I had been up for nearly 3 days straight, and seeing what I drew, made me laugh, although it is correct) will stop the alarm until the vehicle is taken out of reverse. 

The power that normally would be powering the alarm (either directly, or giving a signal to a controller) gets taken away when the relay is turn on. The relay is then actually routing that power back to itself, so it keeps itself turned on until the the 12 source (backup lights) are gone.

As you said you are using a controller, all of this will most likely be in the cab I'm guessing, so use the 12V from the backup lights as the +12 lead to the push button as well, to keep everything on the same circuit.

If you do need to provide power to the push button from another source besides the same circuit the back up lights get power from, then also add two diodes to the mix, one somewhere on the line from the push button to the coil on the relay, and one from the N.O. connector on the relay to the coil. These will keep the 12 from one circuit from back feeding the other (usually wouldn't be a problem, but good to have)

Used to be that Radio Shack used to actually employ people he could recommend the parts and the show you which way to hook them up, now though, the idiots can't even tell you things about products without going and reading the box (same that you can do).

If you need help selecting items, let me know, and I'll look the part numbers up online for ya and post them.

-Greg


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## Antlerart06 (Feb 28, 2011)

greg8872;1412306 said:


> You can do it with two items from Radio Shack
> 
> 1. Push Button (Normally Open [NO]
> 
> ...


My backup beeper doesnt have relay what I did ran 2 wires to the ground side of the beeper and used toogle switch to break the ground works and its safe


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## greg8872 (Jan 17, 2007)

Antlerart06;1413141 said:


> My backup beeper doesnt have relay what I did ran 2 wires to the ground side of the beeper and used toogle switch to break the ground works and its safe


Yes that works, but doesn't solve the issue of the post, using a push button (momentary, not on/off) so that when you move back out of reverse, it is back on next time.

Also to get fancy, if it was me, since you should be shutting of your warning lights between locations anyhow, use the diagram below. This one gets the power to activate the relay a feed going to your warning lights. This way, once lights are on if you disable the backup alarm, it remains disabled until either you shut off the warning lights, or you press the "Reset" button.

This also shows a LED indicator so that you know it is activated.

For those who may wonder, this does NOT mean warning lights need to be on for backup alarm to normally function.

-Greg


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## chuckraduenz (Jan 4, 2009)

i use to do police equipment installs. and we used the same idea "when you push a momentary switch to either turn of or turn on either there opticoms, or sirens" and then would reset when there lights were turned off. 

i know it involves a relay and a few diodes. ill have to look for my wireing diagrams and see if i can figure out how to do it the way you want it done.


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## cameo89 (Dec 8, 2007)

all I did about 3 yrs ago was attach the pos to the reverse signal and ran the ground to the cab "switch" then grounded switch in the cab, I can turn on/off with the flip of a switch! im sure the others will be better with relay but this works for me!


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## Fr0sty (Jan 2, 2012)

imo just switching the ground would be the easiest,quickest & most simple way to achieve what the o.p wants
run the ground wire for the backup alarm into the cab into one side of the switch and then ground the other side
beep when switch is on, no beep when switch is off


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