Introduction: Soil Moisture Sensor Test Plan

Challenge: Design and execute a plan that will light a RED LED when the soil is wet, and a GREEN LED when the soil is dry. This will involve using a Soil Moisture Sensor.

Goal: The goal of this instructable is to see if it has rained and if the plants are receiving water. If the soil is wet, the red LED will light up and if the soil is dry, the green LED will light up. This way, it will help the person who is taking care of plants to test the soil with the Soil Moisture Sensor and give the plants water if they need it.

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Step 1: Step 1: Gather Your Materials


  • Jump Wires
  • Soil Moisture Sensor
  • Yellow LED
  • Blue LED
  • Breadboard
  • Arduino Uno Micro Connector
  • Wet and Dry Soil in Beakers

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Step 2: Step 2: Connect

Connect the wires and moisture sensor to the Arduino board as specified in the diagram. Once the circuit is built, upload the code in the attached document to your Arduino. Once uploaded, open a Serial Monitor window to see if the setup is working. You should see a value at or close to 0 when the sensor is not touching anything. To see it sense moisture, you can grab both probes with your hand. The moisture from your body will be enough for the sensor to detect.

(The picture of the code above is a preview, you must download the attached PDF to be able to copy the code)


Step 3: Step 3: Final Wire and LED Connections

After confirming that the Serial Monitor is depicting the right values, you must attach the rest of the wires and the LEDs as the pictures clearly demonstrate above.

Step 4: Step 4: Final Code

Copy the code attached from the document above and upload it the new Arduino setup.

(The picture of the code above is a preview, you must download the attached PDF to be able to copy the code)

Step 5: Step 5: Test It!

Now that the entire setup is complete, open up the Serial Monitor window once again. Take the dry soil and place the Soil Moisture Sensor into the soil. If the blue LED lights up and the Serial Monitor says values less than 600, the setup has worked! On the other hand, for the wet soil, the Serial Monitor should have values above 600 and the yellow LED should light up. If both of these situations happen, then your project has been completed!

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