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Hydreon RG-15 Solid State Rain Sensor~

This feature is not included in precompiled binaries

When compiling your build add the following to user_config_override.h:

#ifndef USE_HRG15
#define USE_HRG15    // Add support for Hydreon RG-15 Solid State Rain sensor (+1k5 code)

The Hydreon RG-15 Solid State Tipping Bucket is a rainfall measuring device intended to replace conventional tipping buckets.

The RG-15 uses beams of infrared light within a plastic lens about the size of a tennis ball. The round surface of the lens discourages collection of debris, and the RG-15 has no moving parts to stick, and no water-pathways to clog. The device features an open-collector output that emulates a conventional tipping bucket, as well as serial communications that provide more detailed data and allow for configuration of the device.

Find out more on the manufacturer's website.



V+ 3.3V (8) 3.3V
RS232 Out (4) GPIOx
RS232 In (5) GPIOy

Tasmota Settings~

In the Configuration -> Configure Module page assign:

  • GPIOx to HRG15 Rx
  • GPIOy to HRG15 Tx


Sensor90 can be used to configure the rain sensor

Tasmota Display~

After a reboot the driver will detect the sensor and show the sensor data. An example is given below:

Item Value
RG-15 Active 0.01 mm
RG-15 Event 0.13 mm
RG-15 Total 26.8 mm
RG-15 FlowRate 0.32 mm.h

This data is also part of the tele/%topic%/SENSOR payload:

    "Time": "2021-08-25T17:15:45",
    "RG-15": {
        "Active": 0.01,
        "Event": 0.13,
        "Total": 26.80,
        "FlowRate": 0.32
    "TempUnit": "C"


The sensor data is made available over MQTT as per the configured TelePeriod. Additionally, instant telemetry messages are sent during active rainfall events. The sensor will report additional accumulation every 5-60 seconds. The driver resets the Active and FlowRate values to 0 if no additional accumuatlion is detected after 60 seconds.