This rain gauge features a classic tipping bucket design for accurate rainfall measurement, perfect for DIY weather stations. Powered by an ESP8266 microcontroller and integrated with ESPHome, it seamlessly connects to Home Assistant for real-time data tracking. Designed for precision and reliability, this project offers an affordable and customizable solution for monitoring rainfall with high accuracy.

Material list:

9pc - M3 x 6 Brass Inserts  (AB012)

9pc - M3 x 12 FHCS Screw (AA087)

1pc - D6 x 3 Round Magnet (CA007)

1pc - 49E Hall Effect Sensor

1pc - BME280 (optional)

1pc - D1Mini (ESP8266 / ESP32)

wires and connectors

optional when using the 37mm attika mount

2pc - M5  brass inserts

2pc - M5 x 20 Screws

Printing

The Magnet for the bucket is inserted during print. You have to select pause in Bambu Studio on layer 18.

Assemby

Add the brass inserts to every hole.

For the bucket use a piece of filament. The bucket has to tip easily. If not. you can drill the holes on the bucket with a 2mm drill bit to widen it a little bit.

Electronics

The hall effect sensor has to be glued in the indent on the electronics box.

For the optional BME280  use 2,54mm connector glued to opening in the electronigs housing

The BME280 can be inserted from underneath and easily replaced.

Solder the D1mini and place it inside the Box.

Calibration

For calibration mount the gauge in its final position. Be sure to make it level. Take a syringe and fill the bucket with exactly 7ml of water.

Turn the calibration screws until the bucket tips. Do the same with the other half of the bucket.

Every Bucket Tip is the equivalent of 0,64mm rain. (0,64l /m²)

Opening Area: ~11000mm² (10.929 mm²)

Bucket volume: 7ml

Coding for ESPHOME

esphome:
 name: rain_gauge
 friendly_name: Rain_Gauge

esp8266:
 board: esp01_1m

# Enable logging
logger:

# Enable Home Assistant API
api:
 encryption:
   key: "yourkey"

ota:
 - platform: esphome
   password: "yourpass"

wifi:
 networks:
 - ssid: !secret wifi_ssid1
   password: !secret wifi_pass1

 manual_ip: 
   static_ip: 192.168.1.100
   gateway: 192.168.1.1
   subnet: 255.255.255.0

 # Enable fallback hotspot (captive portal) in case wifi connection fails
 ap:
   ssid: "Rain Gauge Fallback Hotspot"
   password: "yourpassword"

captive_portal:

globals:
 - id: rain_mm_per_tip
   type: float
   restore_value: no
   initial_value: '0.64'
 - id: rain_count
   type: int
   restore_value: false
   initial_value: '0'
 - id: rain_count_10
   type: int
   restore_value: false
   initial_value: '0'
 - id: rain_count_60
   type: int
   restore_value: false
   initial_value: '0'

i2c:
 sda: 4
 scl: 5
 scan: True

sensor:
 - platform: bme280_i2c
   temperature:
     name: "BME280 Temperature"
     oversampling: 16x
   pressure:
     name: "BME280 Pressure"
   humidity:
     name: "BME280 Humidity"
   address: 0x76
   update_interval: 60s

 - platform: template
   name: "Regenrate"
   unit_of_measurement: "mm/min"
   icon: "mdi:water"
   accuracy_decimals: 2
   update_interval: 60s
   lambda: |-
     int count = id(rain_count);
     id(rain_count) = 0;
     return count * id(rain_mm_per_tip);

 - platform: template
   name: "Regenrate_10"
   unit_of_measurement: "mm/min"
   icon: "mdi:water"
   accuracy_decimals: 2
   update_interval: 600s
   lambda: |-
     int count = id(rain_count_10);
     id(rain_count_10) = 0;
     return count * id(rain_mm_per_tip) /10;    

 - platform: template
   name: "Regenrate_60"
   unit_of_measurement: "mm/h"
   icon: "mdi:water"
   accuracy_decimals: 2
   update_interval: 3600s
   lambda: |-
     int count = id(rain_count_60);
     id(rain_count_60) = 0;
     return count * id(rain_mm_per_tip);      

binary_sensor:
 - platform: gpio
   name: "rain gauge bucket"
   pin:
     number: 14
     mode: INPUT_PULLUP
     inverted: true
   filters:
     # Entprellen
     - delayed_on:  10ms
     - delayed_off: 10ms
   on_state:
     then:
       - globals.set:
           id: rain_count
           value: !lambda 'return id(rain_count) + 1;'
       - globals.set:
           id: rain_count_10
           value: !lambda 'return id(rain_count_10) + 1;'
       - globals.set:
           id: rain_count_60
           value: !lambda 'return id(rain_count_60) + 1;'