Anyone interested in an open source motion sensor?

Hi !
I’m a hardware engineer and I really like Home Assistant. However, I find annoying that any hardware we use is either some cloud connected devices we hack or local devices we flash with custom firmware.
I have developed PIR sensors for my company and was thinking about making one fully open source with the possibility to sell the hardware already assembled (of course I can’t promise to sell it like a consumer product because legislation cost a fortune, but as a dev kit it will be fine).
So I need to ask : are you interested on such hardware ?
If so, what type of connectivity do you want ? (Wi-Fi, Bluetooth, ZigBee, 433mhz)
Working on batteries or not ? Lithium or disposable ones ?
What kind of price do you expect from such a product ?
Thanks in advance for your replies !


Well, any zigbee motion sensor can be used locally (no cloud) without any hacking, tbh.

When I started my home automation journey, I bought an (expensive) Hue motion sensor, and it’s now happily connected to my HA Yellow without any hacks.

I honestly don’t have any cloud dependent motion sensors out of the 20 or so that I have, Zigbee and Z-Wave are local protocols.

There is probably an audience for an open source motion sensor, if it’s your passion to do it then you should!

No cloud motion sensors here either…
Some rf433, some zigbee… 2 HA set-ups and buildings.

It constantly surprises me that people think that IOT usually needs a cloud connection. It does if you buy expensive proprietary gadgets, like Hue or Tuya.

I have several motion sensors here. Some Zigbee and a couple of DIY sensors where I added a PIR sensor to a Sonoff Basic, flashed with ESPHome. (No cloud)

Zigbee- I would like to see a Zigbee PIR sensor that is powered by battery. But, I haven’t seen anything open source that used Zigbee. Probably because of the Zigbee Alliance requirements.

Bluetooth- range is too short.

WiFi- Probably the easiest for open-source, but it has to be powered full-time (battery killer). Battery replacement will be unreasonably frequent.

433MHz- I do have some switches/buttons on 433. Long range and very battery conservative, but I am unaware of an easy 433MHz interface to Home Assistant. I use a Sonoff 433MHz bridge flashed with ESPHome, but that is not an easy vector for the average user. But, I haven’t seen a 433MHz PIR sensor.

Batteries- Lithium batteries are disposable. Depending on the product size, I personally prefer AAA lead-acid batteries because they are the cheapest.

What price? Since I can build my own WiFi PIR sensor for under $10… Make your own conclusion.

What would I like to see- I would like to see a plug in (line-voltage) WiFi PIR sensor flashed with ESPHome. The flashing pins and a few empty GPIO pins should be on the board for user hacking.

A lot of people have moved on to using mmWave presence sensors (myself included, although I still use a PIR sensor in combination). If you could develop a battery mmWave sensor, I would be very interested :wink:


Well, a combo IR + mmWave would probably be better. But I think we even have those now.

There are already such projects, like Everything Presence One for example.
This is WiFi based, but Matter is coming, so a Matter sensor would probably be nice.


Was going to mention the EP1. They’re great units and the lite version is likely good enough for most things with the older (and more sensor rich) being good for nearly everything else.

mmWave is power hungry. You’re not likely to see a battery operated one because of how they operate.

I have both Aqara Zigbee PIR’s and a Fibaro z-wave one, both on batteries. Both already lasting so long I can’t remember how many months, definitely more than a year, maybe more then two.

I know mmWave is power-hungry, hence the :wink:

Battery-powered mmwave sensors already exist, but the general consensus seems to be that they’re a bit meh.

It’s becoming pretty obvious that you can’t have decent battery life and constant monitoring in the same package. It’s either one or the other, not both.