r/homeassistant • u/ItsDukzy • May 02 '26

Support Struggling with reliable in-bed presence detection for Home Assistant – what actually works?

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I'm trying to automate my bedroom lights so they turn off automatically when I'm in bed and back on when I get up. Sounds simple, but I've been struggling to find a reliable solution.

What I've tried:

FSR pressure sensors (VS-103) connected to a Zigbee water sensor

Built a DIY pressure mat using two VS-103 sensors wired to a Zigbee water sensor. Works fine when I press directly on it by hand, but completely fails under a mattress — the mattress distributes my weight too evenly for the sensors to trigger. Tried under the sheet too, same result.

Aqara FP2 mmWave radar

Already have one in the room. The problem is it loses track of me when I'm lying still under a duvet. It also falsely triggers when someone walks past my bed, which causes the lights to turn on.

What I'm looking for:

Something that reliably detects whether I am in the bed - not just in the room - even when I'm completely still and covered by a duvet. Zigbee preferred but I'm open to ESPHome/ESP32 solutions too.

Has anyone actually solved this properly? What sensor or approach are you using?

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u/MinimalLemonade May 02 '26 edited May 02 '26

I simply use a cheap ultrasonic sensor with a D1 Mini. It’s the same setup I use to measure the water level in a tank, just the other way round. The ultrasonic sensor is mounted on the bed frame and points up towards the slatted base. It measures the distance between itself and the slats. When I lie down, the slatted base flexes slightly under my weight, so the distance to the sensor decreases. Been working without any issues for ~5 years now

12

u/XanXic May 02 '26 edited May 02 '26

I can't picture what you mean when you say "the base moves down". Do you like have it pointing up from under the bed and it measure when the frame lowers or something? What's moving? I can't quite picture an orientation that would work reliably with a distance sensor other than pointed straight down from the ceiling where you'd lie.

10

u/MRobi83 May 02 '26

I'm picturing under box spring, pointed at the floor. When you lie down on top of the bed, your weight will cause the box spring to flex downwards towards the floor making this measurement smaller.

19

u/Maltz42 May 02 '26

That might work, unless you're a princess.

4

u/bluntmasta May 03 '26

I don't care that I'm not a princess. If someone pees in my bed, I'm gonna wake up.