My home has 1-wire DS18B20 temperature sensors inside every light switch to report the room temperature to our loxone smart home system.
This is a very cost effective way of mounting the sensors. Approx £0.50 for the sensor and £0.50 for the connector. Links to the Aliexpress source are in the components list.
I've attached a screenshot of these working in from our loxone server.
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