Easy DIY Rainsensor

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1

I tested several rain sensors and had unsatisfactory results each time. I also had a rain sensor integrated in my slatted roof that did respond quickly and adequately and it was heated. So I looked for a heated rain sensor and found one at Amazon: the KEMO Rain Sensor 12 V/DC. Only this one needs a 12-volt power supply and it does have a relay to switch with. So a mini 12-volt power supply is also supplied by Amazon. And of course a box where the power supply can be built in and a zigbee transmitter there I didn’t want to use a battery powered unit because then you need both 230volt - 12volt and battery. So looked for a zigbee switch that can be connected to 230volt but doesn’t need high voltage to switch and I found this one at Aliexpress. I tested this one and it has a switching voltage of approx. 3 volts and a few mA switching current so suitable for KEMO’s relay. Below are the components.

  • Kemo Regensensor M152 12v-DC

  • 12 V/DC 10 W mini led-transformator

  • yitydamai ip65 junction bax,100x68x50 mm/black

  • 16a Tuya Zigbee 3.0 Mini Smart Diy Switch 1 Way Control Smart

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Changed symbol and text into rainsensor. Powering up with 230volt. Is switching very fast from rain to dry due to the internal heater in the Kemo rainsensor

2

Which Kemo model did you buy specifically - M152 maybe?

3

It is indeed the M152 Rainsensor of KEMO

4

Hi @HSA1963 - would you mind providing a little more detail around how you wired this arrangement? I’ve got this as reference: https://www.kemo-electronic.de/images/ipics/M152/M152_app1_2160x1620.jpg - I’m interested in this setup due to the heated rain sensor and the fact I use zigbee across most of my home so the mesh is solid.

5

I was able to connect the Kemo M152 to a 12v transformer and detect the relay changes using a Tasmota-based Sonoff MiniR2 switch. The wiring was as follows:

  • M152 Orange/White - 12v Ground
  • M152 Orange - 12v Positive
  • M152 Blue/White - S1 on Sonoff MiniR2
  • M152 Blue - S2 on Sonoff MiniR2
  • 12v transformer & the Sonoff - connected to 220v input

I did change the Switchmode to 15 in order to detach the smart switch relay. Essentially only triggering an MQTT message when the switch changes on the M152.

Thanks for the inspiration @HSA1963 - now I just need to get this properly install this so I can share the rain data with my lawnmower. At least that’s the desired end game.