A simple Soil Moisture sensor. This casing can hold either a Wemos D1 mini or a ESP32 C3/S3 mini boards. I used home assistant and ESPHome Builder to install and configure the microcontroller, however you can use micro python or Arduino IDE, your choice. 

ESPHome Code:

```

sensor:

  - platform: adc

    pin: A0   #Replace this with your GPIO pin

    name: "Soil Moisture Sensor 1"

    unit_of_measurement: "%"

    icon: "mdi:water-percent"

    accuracy_decimals: 1

    update_interval: 3s

    filters:

      - calibrate_linear:

          #Replace the values below with the ones you found.

          # The first number is your DRY voltage, which maps to 0% moisture.

          - 0.50 -> 0.0

          # The second number is your WET voltage, which maps to 100% moisture.

          - 0.26 -> 100.0

      # The clamp filter ensures the output never goes below 0% or above 100%.

      - clamp:

          min_value: 0.0

          max_value: 100.0

      # The median filter helps smooth out noisy readings.

      - median:

          window_size: 5

          send_every: 3

          send_first_at: 1

# ==========================================================

deep_sleep:

 run_duration: 120s

 sleep_duration: 15min

```