Mod-EC FAQ 🤔

ESPHome is the framework that creates the firmware for our modules (and many other hardware sensors). That firmware works within Home Assistant. You can use the ESPHome firmware without Home Assistant, that might look something like an ESP32 communicating with an MQTT server.

Any source of temperature can be used. The component expects a sensor that can provide the temperature in Celsius.

sensor:

  - platform: mod_ec

    id: ec

    update_interval: never

    name: EC

    temperature_sensor: water_temp    # optional: defaults to 25°C

    temperature_constant: 25.0        # optional: defaults to 25°C

    temperature_coefficient: 0.019    # optional: defaults to 0.019

  - platform: dallas

    index: 0

    name: "Temperature"

    id: water_temp

    on_value:

       then:

          - component.update: ec

The ID of the temperature sensor is passed to the mod_ec section as can be seen on line 6.

If there is no temperature sensor, the default value of 25 C is used, which is essentially no temperature compensation.

The update_interval is set to never(line 4), and then called explicitly after a temperature measurement (lines 14 - 16).

Add or edit the update_interval line in the source of temperature. All the examples are setup to take a conductivity measurement after a temperature measurement. This ensures the most up-to-date temperature measurement is used.

Double point is usually sufficient for most purposes. For hydroponics, a lower end around 0.5 mS/cm and a higher end of 5.0 mS/cm is usually a good range to calibrate for. If the expected measurements fall outside of that range, then adjust, keeping in mind the maximum and minimum limits of Mod-EC .

Triple point calibration will provide the most accurate measurements over the widest range. Consider if a wide range is really required before choosing this option.

1. Determine the lowest expected measurement and find an appropriate calibration solution.
2. Clean the probe by soaking in distilled water for several minutes. If deposits are present, soak in vinegar.
3. Submerge the probe into the calibration solution and monitor the readings. They may not be very close to the calibration solution and that is OK.
4. Wait until the readings stabilize.
5. Tell the module to calibrate the low point. measurement.
6. Repeat steps 1-5 for the high point.

Calibration data is stored on the module:
— If there are high, mid, and low points, it will use triple-point calibration to calculate the result
— If there are high and low points, it will use dual-point calibration to calculate the result
— If there is a single-point calibration data, it will use single-point calibration to calculate the results
— No calibration points will result in an uncalibrated measurement

For dual- and triple-point calculations, two numbers are involved:
— reference measurement is what the reading should be. If the probe was in 1.0 mS/cm solution, the reference would be 1.0 mS/cm.
— reading measurement is what the probe is actually reading. If the probe was in 1.0 mS/cm solution, but actually reading 0.9 mS/cm, the reading measurement is 0.9 mS/cm.

All calibration data is accessible (read, write, calibration) through the documented API .

When calibrating, the module expects the labelled mS/cm value of the solution. If the solution is 1.413 mS/cm, 1.413 mS/cm should be passed for all calibration routines if you are also passing the solution's temperature. The module will calculate the temperature-compensated value itself.

You will see an immediate change after performing a high and low point calibration. A middle point isn't needed, but it does increase accuracy over a greater range of measurement if that is required.

If the solution used is 1.413 mS/cm, 1.413 mS/cm should be passed for all calibration routines if you are also passing the solution's temperature. The module will calculate the temperature-compensated value itself. If temperature is not passed (not recommended), then pass the compensated mS/cm value.

The great thing about Home Assistant is that you can do whatever you'd like. If you want to change the calibration buttons to something else, that's totally fine. If you are happy with what you've made, get in touch with us and let everyone know.