I have bought a couple of these:
https://www.aliexpress.com/item/1005010469339181.html
I would like to run them via my Zigbee controller (i.e. no tuya app etc.) but although they pair successfully, the readings, especially humidity are totally incorrect.
Do I need to install something else, or are they just not very good devices?
Tuya is a chip manufacturer not a device manufacturer. The devices are created by thousands of companies, some are good and some are bad. Some can write firmware, others cannot.
With Tuya, Buyer Beware.
Both of the above.
It’s very possible that they’re not very good, though the reviews state they’re quite accurate.
It’s also possible to calibrate temperature & humidity, at least if you’re using Zigbee2Mqtt. The device page on Z2M shows that calibration is possible for both Tuya TH09Z control via MQTT | Zigbee2MQTT
If you’re using ZHA, it might still be possible to calibrate them, but you’ll probably have to search around for the proper cluster command to send.
Thank you both. I will bin them and stick with the Sonoff devices which I have found to be excellent.