🪑 DIY Zigbee bed/chair occupancy sensor

I want to share with you how I created a chair occupancy sensor for $10. I have a motion sensor in my room, that toggles the lights. However, the lights often turned off because I’m not moving that much in the chair. So I had to find a solution for that.

What you need:

Start by taking the Aqara sensor apart, till you only have the pcb.

From the car seat sensor, pull the wires out of the connector. Then, solder them to the ends of the magnetic sensor on the Aqara pcb, like below. It does not matter which sides the black or red wires are soldered.

If that’s done, you can put the battery back in and pair it with Home Assistant in the way you prefer (ZHA, Zigbee2Mqtt). Once it’s paired, test it.

Next step is to put it in your chair. I had to rip apart the fabric from the bottom part of the chair to get the sensor under it, but most chairs have a zipper which makes it easier and cleaner to do.

The end result is a battery powered Zigbee chair occupancy sensor!

More Aqara hacks:


Odd question, how quickly does that respond to stimulus? (I’m curious if that sensor could work as a dance pad sensor)

Very cool though.

It’s instant, like milliseconds. Thanks!

I need to find a way to install one of these inside my toilet seat :sunglasses:


just slap the Aquara sensor to the side of the toilet with one bit on the seat, ive done this to prevent the motion lights going off while i read on my throne and it works great, also got an aqura humidity sensor in the shower so when im in the shower it stops them going off as well.


So you could also use it as a bed occupancy sensor?

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Not tested, but it should work.

Does the sensor go below the fabric of the seat or underneath the foam padding as well? How thick do you think the foam could be? Do you think the sensor could trigger under a sofa cushion, for example?


See :point_right: Zigbee Bed occupancy sensor

that thinking out side the box chair


Great project :+1:!

Question, I’m thinking of using this as a bed sensor… But will the mattress be too heavy (will it set the sensor as always on?) Or can you calibrate to different weight?

Thanks! I can’t test it now, but it should work. The only way to calibrate it, is to put something between it, a layer of foam for example.

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I did here

works good

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Wow, didn’t know about those car seat sensors, looks like the perfect solution, I’m definitely going to try this out!

I’ve picked up a set of four load cells (50kg each, so 200kg allowed for the bed). I’m planning to wire that up and make an mqtt sensor that reports the weight on the bed. Here’s a youtube on the build… firmware links are included in the description: https://www.youtube.com/watch?v=VCEgeDN0RLw


This is amazing. Im going to start music playlists on my google home speaker when the shower gets turned on during the morning. TY

Thanks for sharing! Never could find any pressure sensors when searching them on Ali. Never thought of searching for a car seat, great solution.

I’m going to use this as a bed sensor, if it doesn’t work I’ll revert to Velostat which I still have laying around.
And as a office chair sensor :slight_smile:

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I guess I have a solution.
My bathroom has two sensors. PIR and door sensor.
PIR sensor sets timer for 15min after last motion (basically infinity). Door sensor sets same timer to 20sec.

So you have light once you open door, no need to wave for PIR to engage. Once you are inside PIR resets timer for 15min. If you go out light goes off in 20sec. If someone came in on the same go, PIR will keep light on.


That’s a pretty good idea! My kids usually don’t close the door all the way which is a bit of a problem but I think I could put the door sensor over near the hinges to account for that.

You can also use the Aqara door sensor to detect if the door is locked.

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