Retrofit Existing Security System with Wyze Sense Sensors

I’ve seen a few others tear apart the sensor and realized there might be an opportunity to integrate my old hard wired security system along with Wyze Sensors without tearing apart my hard wired system.

I know there is a system out there called Konnected that essentially does the same thing but that would mean another app and it appears the need for a smart things hub if I wanted to automate cameras, plugs, lights, etc, (plus the cost appears higher for my 8 zones)

The thought:
Using the wires from my door and window sensors terminated inside the security panel, I could wire in a Wyze sensor for each zone to be tripped between open and close based on the status of the wired sensor. Rather than than magnet tripping the Wyze sensor reed switch, the Wyze sensor reed switch circuit would be completed or broken based on the wired sensor of my existing security system. This would also allow my to keep my existing system in place but add remote monitoring and automation through Wyze and IFTTT.

I think this would work and would only require $40 in sensors to monitor my 8 door sensors giving me automation with Wyze plus all the features of the Wyze app.

Any one else try something like this? Any thoughts or things I might be missing?

Sounds like an interesting DIY project! I’m no electrical engineer so I can’t offer any input on how best to accomplish this, but I know others have replaced the reed switch with two wire leads to make a water sensor. The key is finding a way to open or close the circuit in a way that’s consistent. I’ll leave it to other more electrically-experienced users to offer suggestions there.

If you do end up trying it please post pictures of your setup!

In doing some testing of my existing system, I determined the wires at my security panel that come from each door sensor complete a 12v circuit and carry 12v current when opened. I think if I wired the Wyze sensor into this circuit, it would complete the wyze sensor circuit as expected but I would be concerned about feeding voltage through the Wyze sensor that does not have voltage currently. I think I would need to add a diode or a 12v triggered relay to isolate the voltage from the security system to avoid impacting the Wyze sensor.

Could you have the 12V current drive an electromagnet to replace the regular magnet? I guess you’d end up with reversed notifications because the current flows when your existing sensor is open, but using an electromagnet would avoid tampering with the Wyze sensor completely.

Have you seen the DIWyze video where the guy hooks up a water sensor to the Wyze sensor circuit board?

Is your plan to disconnect the existing system, or hook up Wyze in parallel? If you’re simply trying to add wireless capability to an existing sensor by having Wyze trip at the same time as the existing sensor then it might not be too hard (though I don’t know why you wouldn’t just attach the Wyze sensor as-is next to the old one?).

I suspect a little more than just 2-wire soldering like in that video for you if you want to leave the existing system functioning. My simplest suggestion would be get a big nail and wrap one of the wires going into/out of the existing sensor around it a dozen times or so and set the Wyze next to it. Hopefully enough current flows when the sensor is triggered to create enough magnetic field to trigger the reed switch.

My next suggestion would probably be a tiny relay. You would hook up the “activation” pins to the 2 existing wires going into the existing sensor (anywhere, either right at the sensor or back at the control panel), and the output ones to the Wyze sensor. When the existing sensor is tripped the voltage between the input and output wires will drop to zero and the relay will release the armature and that will close the circuit on the Wyze triggering an alert. This is assuming your existing system isn’t sensitive enough to detect the relay. You could get a similar result with just a transistor and a handful of resistors, but would require a little more soldering and design.

Interesting idea, I could get around the reverse notifications possibly using IFTTT. I could experiment without permanently changing anything.

Thanks for that link - this is helpful and exactly what I was thinking. I am thinking to hookup in parallel.

Reason for not hooking up as is next to the old one is they are in the door frames and radio connection is spotty across the house - having them all in one place improves radio communication with one central bridge and camera. It also makes install easier without having to drill out door frames, etc. to hide the sensor inside the door or wall by the existing magnets, etc. and then also make a way to change battery later. If I didn’t hookup in parallel, then I could just use the wires from the old sensors without the relay to isolate the 12v. I am looking at possibly using a relay like this one 12v triggered relay

I don’t think I fully understand. Are you keeping the existing alarm infrastructure too, or tossing the alarm system and just re-using the sensors? If you’re trying to keep the existing alarm system intact then you might need a voltage divider on the input, as the control circuit is 5v not 12v.

If you’re going to toss the old alarm system and just want to reuse the existing sensors and wiring, you might get away with literally just wiring the 2 sensor wires to the 2 reed sensor contacts on the Wyze sensor (and remove the reed switch). The issue I see here is the Wyze might be too weak to power a wired sensor across a whole house. If it can power the sensor you will probably find the battery dies rather quickly and you might want to consider further sensor modifications to connect a power supply instead of a button cell battery.

Or, toss the old alarm system, then wire a solid 5v to one of the wires on each existing sensor, and hook a relay to the other end or use something like that board you linked. Then the Wyze sensor would be wired to the relay switching ends.