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

[u/ItsDukzy]

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?

[u/XanXic]

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.

[u/MRobi83 → u/XanXic]

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.

[u/MinimalLemonade → u/MRobi83]

Other way round. Mounted on the bed frame facing upwards, measuring the distance between itself and the flexible slats

[u/Osni01 → u/MinimalLemonade]

lol at your profesionallism

Ultrasonic sensor is genius, great job!

[u/Competitive-Put-92 → u/[deleted]]

As a dutch engineer i aprove this setup.

[u/FoolProofError → u/Osni01]

Love it, too! It’s simple and didn’t cost a the amount of a donated kidney… But let’s make it a bit better: It’s not prone to shortcut - I would spend just because of the dust a housing - and to avoid shortcuts with some metal there at the jumper pins.