Temp/Humid sensors to start with

Hi, i’m new to HA and Smart-Home, but have electronics background. After installing HA on a RP4 in my home network, i want to log about 10-15 positions in my house, starting from my central heating (Gas powered) up to rooms and radiators.

Before i start to build something from scratch, i wonder what would be the most efficient way to do this? As the measure points should be variable, it would be great if they can be radio controlled (Wifi, Zigbee, DECT, whatever), battery powered and have sensors with about 1-2 m cable.

Temperature range? Does it have to have a cable?

Wireless sensor tags?

Some motion sensors also do temperature (Philips Hue).

The sensors i’m looking for are for indoor use only, measuring the heating parameters. So from 10-100° Celsius, but operate in 20-70°.

I also want to have some precise results, at least 0,5° but better 0,1° resolution. Don’t know if the cheap ones can deliver this?

Hi holi,

I am in the process of developing for myself some wireless WiFi temp/humidity sensors to monitor some rooms at home. At the moment I’m waiting for some parts to arrive, to continue with development.

Some infos:

ESP8266 ESP12-F boards without USB!
(boards with USB controller pull to much current even in deep sleep)
Flashed with Tasmota
SHT30 Sensor (0.2°C temp resolution, range is -40 - 125°C)
Data connection between Sensor and HomeAssistant with MQTT.
Batterypowered with one 6500mAh LiFePO4.
Logging intervall 20min, with deep sleep in between.
Estimated runtime with one battery about 180 days!
cost for esp, sensor and battery is about 15 euros.

HomeAssistant logs temperature, humidity, dew point and battery voltage
So if battery voltage gets low, I can get alarm to replace battery.

As soon as I have the missing parts, I can do further development and testing.

Thanks, @chrismaddahl, i’ve investigated into some sensors and found that even plain DS18B2 is more accurate than DHT11 oder DHT22… Thinking of using some of those as they can be connected in parallel on a 1-Wire Bus, so no interface is needed, only one IO pin. And those are available prebuild in da metal shell with a cable attached.

Don’t know if that is helpfull for anybody, but here are my current results of the research:

The other option is to use standard PT100 or PT1000 sensors. They are available in many different kinds and housings. Of course you need an extra component to translate the current-driven sensor to a digital signal, e.g. using a MAX31865. Would be cool to have a support for those kinds as well…

Where i can’t plug in a power supply, i would use Zigbee nodes, as they need much less power than Wifi.

One thing to keep in mind that many of the mentioned sensor exist as clones out in the wild and they are often not within the specification of the original product :warning:

Here are some interesting tests made for various i2c humidity sensors :point_left:

I use a setup which also includes a esp but is a little less DIY but still quite accurate for room temp/hum monitoring:

Runtime of the Hygrometer is about one year (batteries were included for me when I bought the pack of 4 for around $14 - yes! That’s $3.5 for one of this little ble hygrometers with display :money_mouth_face:)

Yes, I have seen the bluetooth proxy stuff a few days ago with the release notes of the last HA Core update. Very interesting.
I have already ordered one LYWSD03MMC from aliexpress to test that.
That would be much less work.
Unfortunatley shipping takes about two weeks.