I recently build successfully a mysensor node based on an Arduino Uno, a Robolink IR sensor and a Robolink DHT11 sensor. The last two from an Elektor sensor kit ever bought for my son when he was still interested by electronics .
My controller is Home Assistant, so I did a merge of the given MySensors example sketch and the Home Assistant example sketch together with the DHT11 sketch.
The airco is a Samsung one, so in the sketch you will find these defines uncommented. Replace by your airco manufacturer.
People interested in building one, can find my sketch on https://github.com/ericvb/MySensorsArduinoSketches
@ToniA a big thanks for the work to decode all these IR sequences!
@kimot I am not handling that situation. I'm taking for granted ssr will do his job. Maybe there's some ssr safety topic I'm unaware? Suggestions for a v3.0 are welcome.
About the temperature measuring... I use two sensors. The one in the board protects electronics from temperatures beyond design (60°C). It's near the ssr because the ssr's derating curve is the most limiting condition.
The control sensor is placed in the bottom of the heater. It connects to the board through a 3 pin header connector.