jwilleke / Grow-Tent

An automation for a Grow Tent

Capacitive Soil Moisture Sensor

Having heard all the issues with corrsion on Reistance Soil Moisture senrors, decided we should look at Capacitive Soil Moisture Sensor

We used the diymore 5pcs Capacitive Soil Moisture Sensor Module 3.3-5.5V Wide Voltage Wire Corrosion Resistant Soil Humidity Detection 3-Pin Gravity Sensor Garden Watering DIY Module from Amazon.

We are currenlty using three of these senors.

• rosemary
• sage
• parsley

NOTE: One of the sensors cables was wired wrong which was very trobling. Check everything!

Specifications:

• Analog output
• Interface: PH2.0-3P
• Size: 99mmx16mm
• Output Voltage: DC 0-3.0V
• Operating Voltage: DC 3.3-5.5V
• Supports 3-Pin Gravity Sensor interface

Testing Voltages for Calibration

These were the ranges acorss the three sensors.

• rosemary - For testing this was Dry (2.12 - 2.18 v)
• Sage - For testing this was in water (2.02 - 2.07 v)
• parsley - For testing this was in soil (.910 - .930 v)

We will scale from 0-100% and this code seems to work well and auto adjust the scaling.

    filters:    
      - lambda: !lambda |-
          if (id(dryValue) < x) {
            // Auto-calibrate dryValue
            id(dryValue) = x;
          }
          if (id(wetValue) > x) {
          // Auto-calibrate wetValue
            id(wetValue) = x;
          }
          // Scale x: dryValue->wetValue, 0->100
          return (x - id(dryValue)) * (100 - 0) / (id(wetValue) - id(dryValue)) + 0;

Our intent is to use home assistant to inturprut the poits where the plants require water.