#Through-wall motion sensing with two $15 ESP32-S3 📡

1 messages · Page 1 of 1 (latest)

buoyant sequoia
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I built a motion detection system that covers my 90m² apartment using two ESP32-S3 boards in diagonal corners. It detects movement through walls across the entire space with just a few small dead zones that could be covered with additional sensors.

Hardware:

  • ESP32-C5, ESP32-C6 and ESP32-S3 supported
  • Works with both external and PCB antennas (external works best though)
  • I used Alfa ARS-N19M for the transmitter and Alfa APA-M25 for the receiver. But most 50 ohm impedance antennas work well

It's more responsive than my current setup with Philips Hue motion sensors in each room.

This runs on my WiFi sensing framework TOMMY (https://www.tommysense.com), which I originally developed for researchers. I'm working on a Home Assistant integration and also adding Raspberry Pi support (3B+/4) soon.

Planning to expand beyond motion detection to full presence sensing including breathing and heartbeat detection.

If anyone's interested in testing the HA integration when it's ready, let me know!
Happy to answer questions about the setup.

Update
The first alpha version is being released in a couple of days 🚀 Join the TOMMY Discord channel to get access (https://discord.com/invite/dKPYKkXQjN) - everything is processed locally on-device and it's free.

shy glade
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I am very intrigued. Although I can’t say I fully understand what this all does. Checking out the website it says “WiFi sensing” then later mentions motion detection. If motion isn’t the sensing then what is it sensing? Perhaps I’m just misunderstanding the description.
Anyway, cool stuff!

buoyant sequoia
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@shy glade Wi-Fi sensing is an emerging technology which tracks the interference humans have on wifi waves. Even the slightest micro movements (theoretically down to the small "jump" the body makes when the heart pumps) affects the wifi signal.

By analyzing these changes in the signal it's possible to infer things like motion, breathing, heart rate, fall detection, human identification, VR control without physical devices etc. - my OP is an example of motion detection using wifi sensing.

It's a pretty cool technology which is expected to rise a lot in the coming years. The upcoming IEEE 802.11bf seeks to standardize the backbone neccessary for wifi sensing.

opaque agate
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Equal parts amazing and terrifying lol

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Following

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My presence detection attempts with BLE beacons haven't been great so this sounds better

buoyant sequoia
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@opaque agate Definitely. It's a techology that comes with risk for misuse. I have created an educational site about wifi sensing here https://wifisensing.io - Under risk->examples you can read about how this can be used to turn routers into cameras. A lot of these risks for surveillance are something researchers are working on

shy glade
buoyant sequoia
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@shy glade Yeah, I can see how the site is pretty vague. It's primarily made for researchers, but I should probably also make it more easy to understand for newcomers

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I actually haven't heard about it for zigbee or thread. Sounds interesting. I should read up on that.

shy glade
buoyant sequoia
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Ah yes I think that's what they call SpaceSense. The company Wiz which they bought was using wifi sensing inside the light bulbs. I heard they promised all Hue bulbs would support it at some point. Pretty cool and a good idea since people already have a lot light bulbs scattered around the home

burnt copper
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This is a new and exciting technology that I'm very glad to hear about, if only so I can think about the options for countering it in the future.

buoyant sequoia
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@burnt copper That's also on my mind. I'm not concerned with smart home applications where the data stays on-device. I'm more concerned with big corporations owning that data (+ potentially selling it) and the fact that it's possible to install sensors without my knowledge (e.g. routers building it in, people putting sensors around my house etc.).

But then again, I guess we have a tendency to be scared of new technology and then slowly 'accept' the problems. In comparison we have a microphone in many of our devices and a camera in the phone looking at our faces at all times 🤷‍♂️

If you have a interest you are more than welcome to join the discord channel, where there is a topic for discussing risks for misuse and countermeasures. https://discord.com/invite/dKPYKkXQjN

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Also an update on the Home Assistant integration
In a couple of weeks I'll have a first version out which is Matter compliant so it's possible to integrate into Home Assistant, Apple/Google Home etc.
It's designed with privacy and security in mind and all data stays on-device and it works without an internet connection.

buoyant sequoia
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@shy glade Philips Hue just released their version of this yesterday, like we talked about using zigbee. Although it requires a new Hue Bridge Pro and a monthly/yearly subscription.

opaque agate
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Anything to sell subs

narrow merlin
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A subscription to locally use hardware you own? Disgusting.

buoyant sequoia
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And a new 100 dollar bridge

buoyant sequoia
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With regards to the TOMMY Motion Sensor - the first alpha version is being released in a couple of days 🚀 Join the Discord channel to get access (https://discord.com/invite/dKPYKkXQjN) - everything is processed locally on-device and it's free.

buoyant sequoia
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A little update. The project is now out of alpha. There have been a lot of changes in the past few months based on feedback from hundreds of users, so the original post doesn’t reflect the current state anymore. Most importantly, installation is now through a Home Assistant Add-on or Docker container, you can create zones (requires 2 devices per zone), more ESP32 boards are supported, ESPHome support, and there’s a free Community Edition and a one-time purchase Pro Edition. Also this week, a proper Home Assistant integration is being released.

You can find more information at https://tommysense.com and you are very welcome to join the Discord community https://discord.com/invite/dKPYKkXQjN 🙂

TOMMY
TOMMY Motion Sensor

TOMMY transforms ordinary Wi-Fi devices into motion sensors that detect movement through walls and obstacles. Easy to install, integrates with Home Assistant or Matter, and creates zone-based motion sensors for smart home automations.