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Mod-EC for ESPHome and Home Assistant

Microfire

Microfire

• 2 min read

In this write-up, we will install ESPHome to get water conductivity measurements into Home Assistant.

  • We will be working in a terminal and using a few commands
  • You'll need a Home Assistant installation running
  • An ESP-device
  • A Mod-EC module and preferably a carrier board

1.

šŸ“¦ Install ESPHome

Follow the instructions on the ESPHome website.

2.

šŸ Start a project

Type esphome wizard mod-ec.yaml in the terminal. Make sure the path on the terminal is where you want the project to be. Follow the steps, and there should be a .yaml file in the directory you ran the command in. For this write-up, it will be mod-ec.yaml. If you type esphome compile mod-ec.yaml you should see the project compile.

3.

šŸ’» Add some YAML and code

We'll make a custom sensor component to get the Mod-EC module working. This is done by adding some lines to the YAML.

The YAML file should be changed to the following:

substitutions:
  friendly_name: Microfire Mod-EC
  device_name: microfire-mod-ec
esphome:
  name: $device_name
esp32:
  board: esp32dev
  framework:
    type: arduino
logger:
api:
ota:
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
    ssid: $device_name
    password: !secret wifi_failover
captive_portal:

# import the mod-ec component
external_components:
  - source:
      type: git
      url: https://github.com/u-fire/ESPHomeComponents/

# https://esphome.io/components/i2c.html
i2c:
  sda: 21
  scl: 22

sensor:
  - platform: mod_ec
    id: ec
    name: EC

button:
  - platform: template
    id: ec_calibrate_low
    name: EC Calibrate Low 0.1
    icon: mdi:format-vertical-align-bottom
    on_press:
        lambda: |-
          id(ec).calibrateLow(0.1);
          
  - platform: template
    id: ec_calibrate_mid
    name: EC Calibrate Mid 1.0
    icon: mdi:format-vertical-align-center
    on_press:
        lambda: |-
          id(ec).calibrateMid(1.0);

  - platform: template
    id: ec_calibrate_high
    name: EC Calibrate High 10.0
    icon: mdi:format-vertical-align-top
    on_press:
        lambda: |-
          id(ec).calibrateHigh(10.0);

  - platform: template
    id: ec_calibrate_reset
    name: EC Calibrate Reset
    icon: mdi:restore
    on_press:
        lambda: |-
          id(ec).calibrateReset();

  - platform: factory_reset
    name: Restart with Factory Default Settings

Make sure you change the wifi section to your network and password if you aren't using a secrets.yaml. Check that the i2c section is using the correct pins.

4.

šŸ”Œ Connect everything

Now is a good time to ensure the module is connected to the ESP-device.

  1. Connect the probe
  2. Make the I2C connections:
  • Mod-EC SDA to controller SDA
  • Mod-EC SCL to controller SCL
  • Mod-EC GND to controller ground
  • Mod-EC VCC to controller 3.3 or 5-volt

5.

āž”ļø Upload

Type esphome run mod-ec.yaml It will compile the project and ask you which serial device to upload the code to. After that, you'll see the ESP debug output. If everything goes to plan, you should see a device has been discovered in Home Assistant.

6.

šŸ  Home Assistant

From within Home Assistant, press Settings > Devices & Services and find the device in the ESPHome integration box. Click it and then click where it says 1 Device. You should see a screen with all the information, Mod-EC measurement, and some buttons to calibrate and reset the device. You can create dashboards, scripts, and anything else Home Assistant can do from here.

7.

Going further

This example used a minimal amount of code and hardware. To get an accurate conductivity reading, you'll need temperature as well. Look at the Carrier Board for Home Assistant article to see how it looks with a DS18B20 sensor attached.

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