The device is a plug-and-play sensor for room temperature and humidity. Great care has been taken to design a stylish and aesthetically pleasing device with high safety and performance. The design allows discreet integration when mounting in a home environment. The device has a robust design with an innovative optical tamper function that alerts if the device is opened. A bit in the status message is set if sabotage is detected or restored. The battery level is continuously monitored and a low battery warning is sent when the battery starts to run out.