So I got my garage door into HA last month using BT RSSI for proximity auto-open. Absolute disaster.
First fail: I’m sitting on my couch one night and the garage door just… goes up. Check the logs — my phone’s BT signal somehow leaked all the way to the ESP32 in the garage, hit the RSSI threshold, and HA decided I was “approaching.” I’m three walls and a living room away, dude.
Second fail was worse. I pull into the driveway, stand there like an idiot for like ten seconds, door doesn’t move. Phone had gone into BT sleep or whatever, advertising interval dropped, ESP32 never saw it. Ended up grabbing the remote.
After those two I’m like… okay, RSSI just can’t draw a clean boundary in a garage. Door itself, rails, torsion spring — all metal. Multipath, reflections, the whole thing. Your threshold is either too loose (false opens) or too tight (misses you). There’s no sweet spot, you just pick your poison.
So I started digging around for alternatives. Two things caught my eye:
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iPhones have had UWB since the 11, and some Android flagships too. No extra tag needed — the phone is the tag.
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UWB does actual time-of-flight ranging. Not “guess the distance from signal strength” like BT. A meter is actually a meter. Metal reflections shouldn’t turn 3m into 1m… right?
So here’s what I’m sketching out:
Small UWB+BT module stuck on/near the garage door. I pull in, it TOF-ranges my phone: 3m… 2m… 1m. Bluetooth handles identity so it knows it’s actually my phone, not my neighbor’s. Data goes through an ESP BT proxy into HA. HA gets one clean fact: “His phone, 1 meter.”
Execution stays completely separate — HA decides what to do, triggers a Shelly relay on the existing opener, or talks to whatever smart opener I already have. No cloud, no cracking open the motor, no voiding warranty. Just a sensor feeding HA.
But I’m still on paper, haven’t bought anything yet. Four things I can’t figure out:
1. UWB around metal — garage door, rails, torsion spring, all of it. Does UWB actually stay accurate in that environment, or does metal still throw off the range? Anyone actually tested this?
2. iPhone UWB when asleep — phone in pocket, locked, screen off. Is the UWB radio actually broadcasting, or does it only wake up for AirTag stuff? If I’m pulling into the driveway and my phone’s asleep, will the module even see me?
3. Latency — UWB range + BT identity + ESP proxy + HA processing + relay trigger. What kind of delay are we talking? If sensing and execution are fully separated, is it still fast enough to feel instant, or am I sitting in the driveway waiting?
4. If the sensing layer is completely external, no wiring into the motor at all — would you feel like you’re missing out on the hardcore modding fun, or more like “good, my warranty is safe”?
If this whole thing has a fatal flaw I’m not seeing, feel free to roast me. I’d rather find out now than after I’ve blown money on hardware.