Relay with humidity sensor

Hardware
1

Hello,
I want to make my bathroom ventilator smarter. I want to read the humidity level and switch the ventilator on when humidity is high. Simple, right? So I’m wondering if I can buy some relay on aliexpress (like sonoff basic), solder humidity sensor on it? If it is based on ESP I will be able to read humidity levels and make automations in HA. The size of the final thing should be as small as possible because I want to install it directly into the fan. Any recommendations are welcome.

2

You can add an i2c sensor to either Sonoff Basic and Sonoff Mini (and maybe Mini Extreme, but I haven’t tested those) by using the RX test point (GPIO03). I actually use a Basic and DHT22 to run my refrigerator.

3

Can you please post a couple of pictures of your project and settings?

4

I can share the ESPHome config, but I don’t think I have any pictures of the project. There are a few versions of the Basic with slightly different layouts so you will need to find a picture of whichever version you have for the pin out. I soldered all connections and used CAT3 telephone wire to connect the sensor to the board.

substitutions:
  esphome_name: fridge-controller-diy
  project: Fridge Thermostatic Relay
  button1_gpio: GPIO0
  relay1_gpio: GPIO12
  device_ip: 10.0.0.8
  gateway_ip: 10.0.0.1
  subnet_ip: 255.255.255.0

esphome:
  name: ${esphome_name}

esp8266:
  board: esp01_1m

# Enable logging
logger:
  level: debug

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

ota:
  password: !secret ha_ota_password

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: ${esphome_name}
    password: !secret ap_password
    
captive_portal:

sensor:
  - platform: dht
    pin: GPIO3
    temperature:
      filters:
        - lambda: return x - 1.7;
      id: my_temperature_sensor
      unit_of_measurement: "°C"
      name: "${esphome_name} Temperature"
      on_value_range:
        - above: 5.8
          then:
            - switch.turn_on: relay_1
        - below: 2
          then:
            - switch.turn_off: relay_1
        - above: 6.8
          then:
            - switch.turn_on: relay_1
        - below: 1.5
          then:
            - switch.turn_off: relay_1
    humidity:
      name: "${esphome_name} Humidity"
    model: AM2302
    

switch:
  - platform: gpio
    name: ${esphome_name}_relay
    icon: "mdi:power-socket-us"
    pin: $relay1_gpio
    restore_mode: RESTORE_DEFAULT_ON
    id: relay_1

  - platform: restart
    name: 'Restart ${esphome_name}'
    id: restart_switch

climate:
  - platform: bang_bang
    name: "Refrigerator Thermostat"
    sensor: my_temperature_sensor
    visual:
      min_temperature: 0 °C
      max_temperature: 7 °C
      temperature_step: 0.1 °C
    default_target_temperature_low: 3.1
    default_target_temperature_high: 5.1
    cool_action:
      - switch.turn_on: relay_1
    idle_action:
      - switch.turn_off: relay_1
    away_config:
      default_target_temperature_low: 3.4
      default_target_temperature_high: 5.4

time:
  - platform: homeassistant
    id: homeassistant_time
5

I use my esphome based wall switch (sonoff m5) together with cheap(est?) wireless ble hygrometer from xiaomi.

Thanks to esphome the setup works independently from HA but is completly controlable at the same time.

If you buy a wifi relay with esp32 you can make use of wireless ble hygrometer without soldering and wires.

Before I tried a setup with zigbee but it was so poorly updating that it easily took 10 minutes or more that the extractor started - with esphome and ble it starts within the first minute of showering.