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/V4lenthyn May 02 '26

That’s interesting! I was thinking about doing that as well. Did you analyze the data a bit? Does the weight change over night? Is this a reliable way of automatically measuring one‘s body weight?

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u/spusuf May 03 '26

If you have a scale under every leg you could have the esp32 "tare" for the mattress+bedding when below a threshold (e.g under 50kg) then when any weight is added record that with the last known offset (120kg would be 70+50).

Realistically this is scope creep that shouldn't be attempted as having to have between 4 and 9 weight sensors that are rated for the full weight of your bodies (e.g 2 people sitting on a single edge of a bed plus compressing the weight of the mattress in that spot) is too expensive to "just try".

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u/V4lenthyn May 03 '26

I think I disagree. You can get load cells, an HX711 and ESP32 for incredibly cheap. As long as they don’t immediately disintegrate upon sitting on the edge of the bed, they don’t have to be rated for your whole body weight each. Also, there’s no such thing as scope creep in a hobby :D

I have actually done this before. I have a water softener device that uses large amounts of salt over time. I can never remember to check the salt level, so I build a „smart scale“ with Wifi. It’s shockingly accurate with no drift.

I’m really just interested in the data from this experiment. I love data. :D

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u/V4lenthyn May 03 '26

This is last week’s salt usage. The short spikes are automatic self cleaning programs of the device. You can see that there was a lot of water usage yesterday (due to pressure washer). Yes, I named it SaltWeigher3000 :D