Home Assistant and Zigbee2mqtt for temperature / water leak sensors

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timmmay

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#296170 26-May-2022 12:36

In this thread @mdf and @PANiCnz told me about Zigbee2mqtt for temperature / water leak sensors for use with Home Assistant. At the time I went in a different direction, but now I have Home Assistant working I want to revisit this.

I want general Zigbee support, but my main aim right now is to use Home Assistant as a thermostat for a bathroom heater with no thermostat built in. I have Kasa plugs that do the one off, but I'll need temperature sensors that send the temp back quite regularly - perhaps every minute or when the temperature changes by a certain amount? I may also want to replace my standalone water leak sensors with leak sensors connected to HA, to reduce the number of systems I have, but Yolink might integrate so I might be ok with their system.

A few questions:

Can anyone recommend Zigbee2mqtt hardware to go with my R.Pi4? I have found the recommended adapters page but I don't know which is best.
Can anyone recommend a temperature sensor that sends temp data back every minute, or regularly enough to use as a thermostat?
The distance from the bathroom to the place I keep routers and such is 12 - 15m, through 4 walls. Is that likely to work, or will I need a repeater? If I need a repeater, any recommendation?

Update: here's what I'm trying to achieve.

I have a very small bathroom / laundry (3 - 4 square meters, you couldn't swing a cat in there) that currently has a fan heater with a thermostat on the floor, hooked up to a Kasa timer. I use Home Assistant to turn it on and off on a schedule. I'm getting sick of having a heater on the floor of the small room as I keep kicking it, so I want to put a fan heater on the wall. I can't find any fan heater that can be wall mounted that has a thermostat that turns it off, so I figured I'd get a fan heater without a thermostat and build my own thermostat with Home Assistant.

I have a Heatermate in the cupboard. Problem with that is the location the fan would go would fire directly at the plug / heatermate. I could possibly put the heatermate at the end of an extension cord up beside the fan heater, but that's a bit ugly. I might see if I can work out a way to mount it where a heater mate might work, as that would be the easiest option by far.

davidcole

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#2918917 26-May-2022 13:28

I'm using a sonoff zigbee bridge (small usb powered device) that's I've flashed zigbee2mqtt on it (did require holding on some dupont cables to be able to flash it as tasmota)

And I have a few of the old xiaomi aqara temp sensors running though it. Not sure what their sending time frame is certainly not a minute for a battery device.

Is your heart really set of zigbee? What about shelly HT sensors (and can get a usb base). I thought they had leak sensors as well. But they only really update on temp change or every 10 mins on power (60 mins on battery I think).

But less fiddly that zigbee2mqtt and fit right in to home assistant.

Another option might be the xiaomi bluetooth sensors, they have a display, sold by pbtech, and I think can talk to home assistant if in range of the system. @bartender was using them I thought.

I know you're not generally keep in DIY, but a d1mii plus temp sensor (DHt11 or dht22) and a couple of dupont cables and esphome permanent wired in and can probably be configured for 1 minute update. I have two of these, not running esphome though, but just pure mqtt. THey're my longest running most reliable temp sensors after being though a number of technologies (zwave, zigbee and shelly)

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timmmay

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#2918929 26-May-2022 13:47

Thanks @davidcole. I don't really care what technology I use. I did look at Shelly sensors, but range might be an issue, though the TP-Link Kasa WiFi devices seem ok in the same location. Bluetooth won't have the range unless I have a couple of repeaters, which I don't really want to do.

I'm not really keen on building my own sensors. I could do it, but I probably can't make them look as nice as a commercial device, and I don't have much free time.

The easiest option would be to find a wall mounted heater that has programmable on / off and temperature, but I've been looking for a few years and never found one. Though I just looked on Amazon AU and found one that means I wouldn't have to bother with any of this! This with a TP-link plug, job done :)

russelo

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#2918935 26-May-2022 13:58

I have the Sonoff zigbee bridge for a couple of years but ditch that due to instability.

I'm now using the more reliable Sonoff Zigbee 3.0 Usb dongle. No flashing needed, works out of the box with HA ZHA.

For the water leak sensor, I'm using the Xiaomi zigbee leak sensor. It has already save me a number of times when the washing machine leaked. A single CR2032 battery lasts more than a year.

I'm still awaiting the arrival of the Tuya zigbee temperature sensor so can't comment on it yet.

allio

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#2918976 26-May-2022 15:18

I definitely don't recommend the Aqara sensors if you want updates that fast. Mine report every 15-30 minutes, which is fine (if not ideal) for an oil heater in the bedroom overnight but way too slow for the bathroom.

Last time I looked into something faster the consensus was that everything Zigbee was going to be similarly slow. You either need something mains powered (I think Shelly makes a wifi one) or RF433. Most people use the Acurite sensors and RTL_433 for the purpose - apparently they update reliably every 30/60 seconds with good battery life. Warning - it's a rabbit hole of time and equipment which I decided not to go down. You can use a cheap DVB-T stick as the receiver, oddly enough.

Another alternative: a Shelly 1PM with a temperature and humidity sensor probe addon would be a all-in-one solution for temperature/humidity monitoring and controlling the heater (and monitoring power usage!).

Handle9

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#2918997 26-May-2022 16:12

Another vote for the sonoff usb dongle. It works much better than the conbee I had when I was using a pi.

I’m using zigbee2mqtt but as above you can use the native integration instead.

Edit: the issue you have with temperature sensors is they are designed to be low power. You don’t need a sensor that polls every minute, you need sensor that transmits change of value. You’ll probably need to go through some documentation and try and find a COV temperature sensor.

Bear in mind you for HVAC control you do not ever want control that reacts fast. You want the whole system to react quite slowly. Thermostats normally have a 6-7 minute time constant which is why the RTD is normally attached to a copper plate. It slows everything down and makes it nice and stable.

timmmay

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#2919001 26-May-2022 16:24

Thanks all. The space I am trying to heat is a very small toilet and laundry, 6 minutes on high in the room is a furnace.

It occurs to me that I am possibly thinking too high tech. A simple plugin thermostat would do the job just fine, less flexible, but fine.

I'll probably still do ZigBee water leak sensors sometime so this information is really useful 🙂

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mdf

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#2919118 26-May-2022 17:25

I've got the Aqara Zigbee sensors. According to spec, they will update every 0.5 degree change in temp, or every hour. My real world experience would be along those lines.

However I would be a little leery about using these with HASS completely unchecked. I do use these for some heating, but only where there is another on-device thermostat that will still cut out if something goes wrong (you wouldn't want to burn your house down because the sensors lost connectivity or your SD card packed a sad). You could probably set something up to make sure it was on no longer than half an hour, or a +/- X deg rise, whatever occurs first?

That said, what are you trying to achieve? Turn on the heater remotely, or just keep an eye on temperature? Something simpler like heatermate would perhaps be more reliable (and simple).

In terms of your other queries, I've got the original CC2531 coordinator flashed w Zigbee2MQTT and the range is rubbish. I've added two CC2530 routers (one upstairs and one down) and everything works well now, but some of the more modern boards listed on the Zigbee2MQTT website have much greater range out of the box (though I've not used them myself). I think (?) I've got a spare CC2531 somewhere plus the debugger to flash it if you want to borrow it to experiment, but I almost guarantee its not going 12-14m through multiple walls on its own to a battery device unaided.

FWIW, I am super impressed with Zigbee2MQTT development. The current UI and features have come a *long* way in even the last year or two. Quite a bit simpler and more intuitive.

timmmay

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#2919150 26-May-2022 19:58

Handle9

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#2919161 26-May-2022 20:26

A 230V rated thermostat will work fine if it’s wired in series with a fan heater. Any competent sparky should be able to wire it that way.

Just make sure the thermostat is rated for the correct current.

mdf

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#2919165 26-May-2022 20:33

The Mistral fan you linked to in the Amazon AU link is available at Bunnings. Doesn't seem to come that highly recommended but dirt cheap. Says "adjustable thermostat" but also "two heat settings" so it might just turn itself down once the temperature is reached.

eonsim

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#2919174 26-May-2022 20:53

I would suggest looking at a Shelly 1PM or Shelly 1 with the temperature sensor addon (wifi not Zigbee though). You can get the Shelly wired inline to the power supply for the heater (panel heater would be another option) connect it to the shelly temperature sensor addon and then position the temperature sensor where that it can get a decent reading (might need to drill a hole and mount it behind it). Otherwise you could use a standalone Shelly HT unit but then you have to deal with batteries and potentially less frequent updates compared to the the Temperature sensor addon which is powered by the shelly.

Then in HomeAssistant you can create a generic thermostat entity and link the temperature sensor for the Shelly to the shelly switch and your pretty much done.

Alternatively smart plug (possibly one with a USB socket as well) with a wall panel heater and some other temperature sensor connected to home assistant via wifi (ESP32 using ESPhome, powered by the USB slot).

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timmmay

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#2919462 27-May-2022 15:26

I think for now I'll go look at the heater at Bunnings, I've been looking for 3 years and that's the first wall mounted fan heater with a thermostat. That would be a heck of a lot easier!

I will get around to Zigbee devices with HA at some point, I'll use the advance in this thread then. Thanks all :)

mdf

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#2919537 27-May-2022 17:12

timmmay:

I think for now I'll go look at the heater at Bunnings, I've been looking for 3 years and that's the first wall mounted fan heater with a thermostat. That would be a heck of a lot easier!

I will get around to Zigbee devices with HA at some point, I'll use the advance in this thread then. Thanks all :)

Not nearly as geeky though! You will have to replace the fan with something RGB to re-earn your GZ cred.