We return today to the simple and quick solutions! The weather station or irrigation/sprinkler system – can’t operate without proper detection of rain, water or even snow. Let’s use the FC-37 sensor (also know as YL-38 or MH-RD, or just similar to the picture below)

What will you need?

• rain sensor type FC-37/MH-RD (rain drop/snow sensor) – must come with D0 pin, price around $0.50 to $1.50
• ESPEasy working on ESP8266 from the previous entries

Installation and configuration

• The sensor must be connected to the power supply + 3.3V (3V) and GND of the ESP8266 running ESPEasy. Next we connectthe D0 pin to the selected pin our ESPEasy – which is going to notify Domoticz using IP. Let’s use free GPIO-12 (pin D6 on the NodeMCU v2 board). This sensor also has an analog output – which allows for more advanced detection of rain, and we will deal with in the future.
• Finally – we connect the rain sensor plate with the sensor module that is connected to ESP8266:
  
  Check in the Devices section the IDX number – it’s 543 in this example:
  
  Next – let’s configure via WWW interface our ESPEasy software – selecting the “Switch Input”, entering correct IDX and setting some options – please do mind the “Inversed”, and of courser the correct value of IDX:
  
  Let’s test our sensor! For this purpose you should set the sensor using Philips screwdriver just so that the green LED still does not glow when we apply only dry finger plate (blue cube with white “screw”):
  
  Rain drop sensor setupIf the sensor is correctly adjusted we should get the green LED to glow right after dropping some water on the sensor plate:

plugin:youtube

Of course, when the device is installed outside, the seonsor is protected – we need to re-set it so as not to react not to dew, but the rain or snow.
Domoticz should show us this swithc in the following way:
When there is no rain:

And when it rains:

That's it!