Help with wiring (dry contact relay)


(Nathan Davis) #1

I hope you guys can help me. I’m trying to use a Mimolite (Z-Wave dry contact relay) to control only the light on my garage door, not the garage door itself. After hours of voltage testing and research, I discovered that the light is controlled on the same circuit as the garage door; what’s happening is that my garage door wall switch is simply dividing the input voltage (with two resistors) from 3.94V down to 1.83V when the light button is pressed (when the garage door button is pressed it is still 3.94V). I know how to set up a voltage divider on the Mimolite, but my question is if I buy two resistors that will reduce the voltage from 12V on the Mimolite to around 2V on the COM input, would this accomplish what I need? My hesitation is that there will be a constant 3.94V on the NO input and I’m not sure how that will affect the output voltage. Does any of this make sense?


( I hate Mondays) #2

Why don’t you use the dry NO contact in parallel with the physical light button? It would then simply simulate a button push… Use the COM and the NO (normally open) pins with no power supply attached to them.


(Mike Maxwell) #3

It might be way simpler, and a lot brighter to integrate the ceiling light in the garage vs dinking with the garage door light through the door button.
I don’t think you’re going to be able to simply “trick” the garage door into turning on the light by messing with the pb signal.


(Nathan Davis) #4

The problem with connecting to the wall switch is that I don’t see an easy way to connect the wiring


(Nathan Davis) #5

I know. I’m probably making this more difficult than it needs to be.


( I hate Mondays) #6

Soldering a twisted pair to the back of the button should work, then plug those into the COM and NO of the dry relay. A dry relay means it exposes all relay pins (usually NC, COM, and NO) and they are completely insulated from the relay’s power supply. Make sure it’s a dry relay.


(Nathan Davis) #7

That’s exactly what I was just thinking. Not sure why it didn’t occur to me before. I just recently got back into soldering so I should be able to it. And yes it is a dry relay. Thanks for the response.


( I hate Mondays) #8

Just remember, with ST, you’ll need to turn the dry relay on and off to simulate a push. Don’t leave it on, don’t know what would happen then :wink:


(Nathan Davis) #9

The Mimolite has a momentary jumper option so it automatically “turns off” after a trigger.