Measure and control with precisionShelly Plus Add-on is a galvanically isolated sensor interface for all Shelly Plus relays. Use it to measure temperature and humidity using its 1-Wire terminals, or connect various analog and digital sensors for complex automation and higher efficiency. Highly compatibleShelly Plus Add-on is compatible with most Arduino sensors! Use its digital or analog inputs to measure your desired parameters and create complex automation scenes based on the sensor data. Garage door position You can connect a reed-switch sensor to Shelly Plus Addon's dig