HA-M5StickC - Wifi temperature/humidity sensor for HomeAssistant

M5StickC Plus-based wifi temperature/humidity sensor for HomeAssistant using ESPHome infrastructure.

Once configured, the following entities will be available within Home Assistant:

• sensor
  • Temperature (°C)
  • Humidity (%)
  • Battery level (%)
  • Wifi RSSI (dBm)
  • Uptime (s)
• binary_sensor
  • Button A (front, display control)
  • Button B (bottom)
• switch
  • Led

M5StickC will also fetch temperature and humidity corrections from HomeAssistant to compensate for M5Stick heat leaking into ENV III Hat (see following comment/measurement data). This correction is zero-order/a simple offset as of today.

A typical application uses this device as a temperature or humidity sensor for the HA Generic Thermostat (target_sensor parameter) to control a heater/cooler/fan switch. Led can be used within HomeAssistant to indicate e.g. switch state and button B is available to switch an auxiliary equipment or HA state.

Hardware description

• M5StickC Plus
• ENV III Hat
• Holder for 3D printing

M5StickC configuration

• Install ESPHome, e.g. using docker

  docker pull esphome/esphome
  

• Clone this repo

  git clone https://github.com/jpcornil-git/HA-M5StickC.git
  

• Start ESPhome with configuration folder set to this one, e.g. using docker (replace <full path> with the actual path and, if required, adapt ttyUSB0 [on Windows, replace --device /dev/ttyUSB0 with --privileged]).

  docker run --device /dev/ttyUSB0 -p 6052:6052 -v "<full path>/HA-M5StickC/configuration:/config" esphome/esphome
  

• Start a web browser and navigate to http://localhost:6052/ to access ESPHome dashboard, you should see a new m5stickc_env device.

  

• Edit secrets.yaml (1) and edit/add following credentials ("myOtaPassword" will be used to secure firmware update Over-The-Air/OTA):

  # Your Wi-Fi SSID and password
  wifi_ssid: "myWifiSSID"
  wifi_password: "myWifiPassword"
  # Your OTA password
  ota_password: "myOtaPassword"

• Build and install firmware on your M5StickC (2)

  • Wireless update is only possible once M5StickC is on the network, i.e. after initial (wired) configuration and correct Wifi SSID/password configured.

• Once uploaded, you should see a splash screen on the M5StickC displaying the name of the device for 3 seconds followed by a black screen (screen off by default). Cycle thru available screens using the M5/front button to select a different one:

  [Off] -> [Corrected Temp/Humidity sensor] -> [Raw Temp/Humidity sensor] -> [Network parameters] -> [Off] -> ...

  Corrected Temp/Humidity sensor screen

HomeAssistant configuration

• Edit HA configuration.yaml

  Add/adapt following content to control temperature and humidity corrections (entity names, e.g. m5stickc_env_1_offset_temperature below, have to match devicename in m5stickc_env.yaml). If you have multiple M5StickC, each of them needs two such entries.

  input_number:
    m5stickc_env_1_offset_temperature:
      name: Température offset
      unit_of_measurement: "°C"
      mode: box
      min: -5.0
      max: +5.0
      step: 0.1
    m5stickc_env_1_offset_humidity:
      name: Humidity offset
      unit_of_measurement: "%"
      mode: box
      min: -10.0
      max: +10.0
      step: 0.5

• Restart HA

  You should see a new ESPHome integration.

  

  Example of a lovelace dashboard illustrating M5StickC entities and associated temperature and humidity correction controls.

  

  Note: When you update correction data, it will take up to 30s (update cycle) for these to become effective.

References

• [1] AXP192 Power Management unit (PMU) is reused from esphome-m5stickC