How to Use Adafruit: Examples, Pinouts, and Specs

Adafruit 3695 is a versatile electronic component designed and manufactured by Adafruit Industries, a company renowned for its open-source electronics and educational kits. This specific component is a STEMMA Soil Sensor that measures soil moisture levels and temperature, making it ideal for environmental monitoring and agricultural projects. Its plug-and-play design ensures ease of use, even for beginners.

• Agriculture: Monitoring soil moisture for irrigation systems.
• Gardening: Tracking soil conditions for optimal plant growth.
• Environmental Monitoring: Collecting data for research and analysis.
• DIY Projects: Integrating soil sensors into smart gardening systems.

The Adafruit 3695 is a capacitive soil moisture sensor with an integrated temperature sensor. Below are its key technical details:

• Operating Voltage: 3.3V to 5V DC
• Current Consumption: ~5mA
• Communication Protocol: I2C
• I2C Address: 0x36 (default, configurable)
• Temperature Sensor: Onboard thermistor
• Moisture Measurement: Capacitive sensing
• Dimensions: 100mm x 23mm x 8mm
• Weight: 5g

The Adafruit 3695 features a 4-pin JST PH connector for easy interfacing. Below is the pinout:

1. Power the Sensor: Connect the VIN pin to a 3.3V or 5V power source and the GND pin to ground.
2. Connect to a Microcontroller: Use the SDA and SCL pins to connect the sensor to the I2C bus of your microcontroller (e.g., Arduino UNO).
3. Install Required Libraries: Download and install the Adafruit STEMMA Soil Sensor library from the Arduino Library Manager.
4. Write and Upload Code: Use the example code provided below to read soil moisture and temperature data.

• Avoid Corrosion: The sensor is designed to resist corrosion, but prolonged exposure to water may still degrade its performance. Use it in well-drained soil.
• I2C Address Conflicts: If multiple I2C devices are connected, ensure their addresses do not conflict. The default address (0x36) can be changed if needed.
• Cable Length: Keep the cable length short to avoid signal degradation in I2C communication.

#include <Wire.h>
#include "Adafruit_STEMMA_Soil_Sensor.h"

// Create an instance of the soil sensor
Adafruit_STEMMA_Soil_Sensor soilSensor;

void setup() {
  Serial.begin(9600); // Initialize serial communication
  while (!Serial);    // Wait for the serial monitor to open

  // Initialize the soil sensor
  if (!soilSensor.begin()) {
    Serial.println("Failed to find the STEMMA Soil Sensor!");
    while (1); // Halt execution if the sensor is not detected
  }
  Serial.println("STEMMA Soil Sensor initialized successfully.");
}

void loop() {
  // Read soil moisture level
  float moisture = soilSensor.readCapacitance();
  // Read temperature in Celsius
  float temperature = soilSensor.readTemperature();

  // Print the readings to the serial monitor
  Serial.print("Soil Moisture: ");
  Serial.print(moisture);
  Serial.println(" units");

  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.println(" °C");

  delay(1000); // Wait 1 second before the next reading
}

1. Sensor Not Detected:

   • Cause: Incorrect wiring or I2C address conflict.
   • Solution: Double-check the wiring and ensure the I2C address matches the code.

2. Inaccurate Readings:

   • Cause: Sensor not properly inserted into the soil or interference from nearby electronics.
   • Solution: Ensure the sensor is fully inserted into the soil and keep it away from high-frequency devices.

3. No Data in Serial Monitor:

   • Cause: Serial communication not initialized or incorrect baud rate.
   • Solution: Verify that Serial.begin(9600) matches the baud rate in the serial monitor.

• Check Connections: Ensure all pins are securely connected and there are no loose wires.
• Update Libraries: Use the latest version of the Adafruit STEMMA Soil Sensor library.
• Test with Example Code: Start with the provided example code to verify the sensor's functionality before integrating it into a larger project.

By following this documentation, users can effectively integrate the Adafruit 3695 into their projects and troubleshoot any issues that arise.