You might find Vera is a good choice for you: https://www.mysensors.org/controller/vera

You might also look at these threads https://forum.mysensors.org/topic/2939/humidity-sensor-sketch-too-big-for-arduino-promini/ https://forum.mysensors.org/topic/1220/temperature-sensor-example-on-pro-mini-atmega168-not-compiling https://forum.mysensors.org/topic/3194/signing-problem-with-size