Making a "dumb" luminosity sensor smart?

My house has an old luminosity sensor that’s nicely installed in the garage gable that controls a bunch of outside lights. Is there a way to wire a relay or something to it so i can use that to trigger events based on luminosity? The existing smart ones aren’t as aesthetically pleasing as this one that blends in with the front of the house.

Thank you

First thing that comes to mind is a relay connected to a contact sensor.

Could you please explain how the contact sensor comes in to play?

You would fetch a contact sensor that has a connection for a remote contact, such as a monoprice. This input is then connected to the relays c and no contact.
Light goes on, relay energizes, no contact closes, St gets a closed state event from the contact sensor.


I think what Mike is suggesting is wiring a relay to the connections of a smart contact sensor. Some have auxiliary inputs you can wire to.
So your luminosity sensor would power the relay on, which would close aux input contacts on the contact sensor. Which would send a signal to your hub.

I’m sure others will jump in and give you specifics and examples of which contact sensors have this ability.

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I think I’m following you on that, thank you. Any guidance on what contact sensor offers this functionality is appreciated, I searched for a Monoprice one as mentioned above, but only found the traditional open/close one with no aux inputs.

This is a device feature which comes and goes with model changes. At one point, Schlage, everspring, and monoprice were all inexpensive (under $40) contact sensors offering dry contacts. But I’m honestly not sure about their current models.

One that might be worth considering is Aeotec’s “dry contact sensor” model ZW097 as it is Z wave plus so it will have much longer range than classic Z wave devices. It’s not cheap, but you can usually find it for about $35.

Aeon Labs describes it as “small” but it’s one of the big box type sensors, about 3 1/2 inches long.

Thank you everyone for your responses, this is all great information.

If I understand everything, I don’t need a zwave relay, I just need one of the dry sensors JD mentions (

If I wire the light sensor I have into this one, then once the sun sets, it will trigger the sensor and I can use that to trigger other actions, correct?

Part B of this equation: is there a way to do this using hardwired devices? The connections are all in the attic and I live in Florida. Come July, I’m not going to want to climb through my attic to change a battery.

“Dry” contacts don’t carry voltage. “Wet” contacts can. The purpose of the relay in the middle is to accept the current from the luminosity sensor and provide something volt free that the dry contact device can respond to.

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Okay, that makes sense. So now are there any recommendations on the relay? I know how to do basic wiring, but I don’t know enough about checking voltage and amps to ensure I don’t burn my house down.

If you want to hardwire it, the Fortrezz Mimolite is popular and then you don’t need the contact sensor as it can be wired inline and has its own Z wave radio. But it costs more.

Everyone here is awesome! Thanks!


So I’m taking a closer look into how this works and have a question about wiring it.I see there’s a plug, so I’ll just put an outlet in my attic and plug it in, that’s not a problem.

My question comes in with the input from the luminosity sensor. The device says not to have an input more than 24V DC. If I wire the luminosity sensor into it, doesn’t the sensor send the full 120V AC from my house through it? That seems like a bad idea.

On a different way of thinking, could you install a smart bulb in one of the fittings and have smartthing register when the bulb turns on, which in turn triggers other things?