Looking for wireless motion sensor

Hi there!
we’re looking for a wireless motion sensor, preferably it should work with wifi.
it’s sole purpose would be to notify us when our cat is at the door while we’re watching tv on the couch :slight_smile:
the “thing” should work without “external” server and shouldn’t have a direct connection to the manufacturers home :wink:
so far i don’t have HUE, yeelight, Ikea or anything, all lights are simply controlled by knx…

I’d be happy to get some input form you guys!

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One option is an Esp8266 flashed with Esp Easy firmware and a PIR sensor that uses 3.3v logic. I’ve tested this setup in the past and worked without issue.

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That will be a problem
WiFi is a very demanding power user and there are very few battery powered wifi devices.
I have a Grohe Ondus sense and that only wakes up in case of flood or once every hour to give a quick update. If it was on all the time, the batteries would last about 3 days only.

If you have no way to bring power to the device you will need another wireless technology than wifi for an always on device. And that will mean a dongle of some sort either zwave or zigbee.

[quote=“H102, post:2, topic:52554, full:true”]
One option is an Esp8266 flashed with Esp Easy firmware and a PIR sensor that uses 3.3v logic. I’ve tested this setup in the past and worked without issue.
[/quote]for how long did batteries last?

that make sense… i’ll take a look on how i can bring zwave into the game (can’t put it directly on my openhab-raspberry)…


Yes you can, you need a zwave dongle.
Now, I don’t have zwave but it is one of the most used tech in the forum
So you will have no problem setting that up

I haven’t tested with batteries but have read, with proper configuration, the Esp can last a few months on battery power.

If not a big hassle, you can mount and power (using an extension cord) the Esp/PIR in the soffit above the door.

Have a look at zigbee2mqtt. This Movement/Vibration Sensor may be what your looking for. It is not yet supported, but it is being worked on. Watch the progress here.

Edit: Sorry, was thinking about a cat door. This sensor may be what you’ve been looking for. This already works with zigbee2mqtt. Hints for setting up in openHAB are here.

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Yes it can but that’s only by using deep sleep and waking up once in a while, connect to wifi and report. In the case of the OP we need an always on device with a PIR attached. Unless to OP wants to change batteries every 3 days, the wifi solution is impractical. Unless, of course I missed something.

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i think you got it right. example:

  1. cat’s outside
  2. on my way to the couch i place the sensor outside of the door
  3. i’m watching tv
  4. cat decides to show up (and requests to be let inside) >>> sensor triggered >>> telegram to my phone (or some other action from OH)
  5. cat walks inside and requests food


Hi Peter (@narf27),

I have been happy with this Hue Motion Sensor via the Zigbee binding from recent openHAB 2.4.0 SNAPSHOT releases. I’ve been testing it for about six months now and it has operated reliably for me. The Zigbee coordinator I have is a TI CC2531 plugged into a powered USB hub that is in turn connected to the RPi 3 on which OH2 runs.

It should work for your application, assuming your OH2 system is within “earshot” of your front door.

Good luck!

sadly my oh2 system is “out of range”. so i’d need another zigbee controller that communicates with oh?
with hue bridge it should work via hue binding, right?

Then I recommend that you look into zigbee2mqtt

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I bought a cat alarm mat :slight_smile: Indexa 33620 Alarmtrittmatte Schwarz 95dB https://www.amazon.de/dp/B000UAE1NM/ref=cm_sw_r_cp_api_vgESBb1YEE4W4.

I haven‘t played with it but I’m sure you can easily replace the door bell with a WiFi compatible arduino or raspberrY . And if you succeeded, let me know ok? :slight_smile:

ha! i bet my cat would never stand on this mat :slight_smile:

@papaPhiL i’ll take a look!

a cheaper solution can be the Sonoff motion sensors. They use 433MHz transmission but there is a very wifi bridge that transforms the message to mqtt.
I didn’t test it but it can solve your problem.


something like this? https://github.com/arendst/Sonoff-Tasmota/wiki/Wemos-D1-Mini-and-HC-SR501-PIR-Motion-Sensor
this comes without case, right?

Correct. It’s a DIY solution. And again, this is WiFi, so power will be a consideration.
For all wireless systems that I know off (Except Wifi) you will need a bridge of some sort.
Zigbee or ZWave are very reliable but can be pricier. Zigbee is cheaper than ZWave.

You could also go down the route of 433MHz sensors with a receiver like this:

And a sensor like this:

But in my experience the 433MHz do suffer from interference from time to time and are not the most reliable.

If you’re thinking about going Z-Wave, don’t get the EcoLink 2.5 PIR. I did, and about twice a day reports motion when there is no motion. I emailed EcoLink and they just said that OpenHAB is not supported for this device.

got me a fibaro motion sensor and zwave stick. i hope with zwave mesh network i can reach the door :slight_smile:

I believe it would be quite possible to build a battery operated device with Wemos D1 Mini (or any other ESP8266) and a low current PIR sensor.

I can say this because I built a pretty similar detector for my doorbell but with a reed switch instead of PIR sensor and by use of the ESP deep sleep mode. The reed switch (a regular door sensor to be exact) is glued inside the doorbell, next to the coil of the electromagnet used to move the hammer. The reed switch is connected to a Wemos D1 Mini and used as a reset signal to wake Wemos from deep sleep. When Wemos is woken up, it connects to wifi and quickly makes posts over MQTT and goes back to deep sleep. MQTT is listened by OpenHAB, which then sends me a notification over PushSafer and also triggers ZoneMinder camera recording.

In addition to the actual notification, Wemos posts the battery level (which you can get with ESP.getVcc) to another topic and OpenHAB alarms me when the battery goes low. This whole thing is operated with a single 18650 Li-Ion cell (a cheap 3200mAh from Aliexpress) and I’ve had it run about 9 months with single charge. Of course the battery life depends on how often the chip is woken up.

Reed switch does not use any power but PIR sensors seem to be able run with as low as 50µA in standby mode so it should be possible to run it for months with a single cell as well.

Just my 2¢ even though the OP seems to have found a solution already.