# Fire Station Alert Lighting



## CBello44 (Apr 14, 2016)

Hi there,

I realize this might be a silly problem but I'm a video guy much more than an electric guy.. I'll start by explaining my end goal and then tell you where I've landed. I am trying to put recessed ceiling LED fixtures in to my fire station's sleeping quarters. There are 4 rooms, I wanted to put one fixture in each. Each room would have a wall switch for WHITE light, but the same fixture (all four) would come on in RED automatically when the station received an emergency call. 

I researched DMX and a few other automated routes, but this seemed too pricey or above my skill level. So I bought a simple 12 watt RGB+Warm White LED fixture that comes with an in-line remote control receiver (http://www.amazon.com/dp/B01CPTANIW/?tag=cpf0b6-20). The second I opened the box I ripped that receiver open to figure out its outputs, cut the receiver out of the picture and moved on to old-school 12 volt powering. The wires leftover going to the light are a 12v+ and then 4 grounds (a red, a green, a blue, and a warm white) I also had a 12v PSU and a 12v PWM dimmer wall switch on hand. So you give the 12v+ power, and ground out the white and you get a white. switch the ground to the red and you get red..combine 2 and you..you get the picture.

Okay so where I stand is, I know I can make a switch turn on the light for white which is one of my goals... but now I need to know what to do to override that white light and get the red grounded instead of white when we get a call. When we get a call there is a 12v circuit that closes (right now it powers one rotating light in another room), so I can use that, we'll call it "Alert", circuit to either fire another relay or I can also power the new fixtures off of it entirely..

But if the white light was on and we got an Alert, I'd be sending two power supplies to the same fixture. Or if the switch was off and I was only switching grounds from red to white there would be no 12v+

So basically i know how to make the light do one or the other and I would like some help trying to make it switch between the two modes on command. I'm also taking product suggestions if there is a better fixture for the job.

Thanks!


----------



## broadgage (Apr 25, 2016)

Leave the mains supply into the 12 volt PSU on all the time.
Leave the positive wire from the PSU connected permanently to the positive common connection to the light fittings.
Obtain a relay with one set of changeover contacts, connect the common terminal of the relay to the negative PSU output.
Connect the normally open relay output to the "red light" negative wire to the lights.
Connect the normally closed relay output via a standard wall switch to the "white light" negative wire to the light.

With the relay de-energised, the 12 volt negative is on up to the switch, and the white light may be turned on/off as desired.
When an emergency call is received the relay will operate and interrupt the 12 volt negative to the wall switch(s) thereby extinguishing the white lights. At the same time, the negative supply to the red lights is made and they will light regardless of the status of the wall switch.


----------

