How to Use Disolved oxygen sensor: Examples, Pinouts, and Specs

The DFRobot Dissolved Oxygen Sensor (DFR0237-A) is an electronic device designed to measure the concentration of dissolved oxygen in aqueous solutions. It is an essential tool for environmental monitoring, aquaculture, water quality analysis, and various types of research where precise oxygen levels are crucial for the health of aquatic life or the quality of water.

• Environmental monitoring of rivers, lakes, and oceans
• Aquaculture to ensure the health of fish and other aquatic organisms
• Water treatment plants for monitoring and controlling oxygen levels
• Scientific research in biology, hydrology, and environmental science

• Operating Voltage: 3.3V to 5.5V
• Output Signal: Analog (0-3.0V)
• Detection Range: 0 mg/L to 20 mg/L
• Accuracy: ±0.3 mg/L
• Response Time: <60s
• Operating Temperature: 0°C to 50°C
• Storage Temperature: -20°C to 60°C

1. Connect the VCC pin to a 3.3V or 5V power supply.
2. Connect the GND pin to the ground of the power supply.
3. Connect the SIG pin to an analog input on your microcontroller (e.g., Arduino UNO).
4. Optionally, connect the TEMP pin to another analog input for temperature readings.

• Always calibrate the sensor before use to ensure accurate readings.
• Avoid touching the sensing membrane as it is sensitive and can be damaged.
• Do not bend the sensor probe.
• Keep the sensor stored in water when not in use to prevent the membrane from drying out.
• Use a proper shielded cable if extending the sensor leads to reduce noise.

// Code for reading dissolved oxygen levels using DFRobot's DFR0237-A sensor
#include <Wire.h>

// Analog pin connected to the sensor's output
const int DO_PIN = A0;

void setup() {
  Serial.begin(9600); // Start serial communication at 9600 baud rate
}

void loop() {
  int doValue = analogRead(DO_PIN); // Read the dissolved oxygen value
  float voltage = doValue * (5.0 / 1023.0); // Convert to voltage
  // Convert voltage to dissolved oxygen concentration (mg/L)
  // The conversion factor will vary depending on calibration
  float concentration = voltage * (20.0 / 3.0); 

  Serial.print("Dissolved Oxygen (mg/L): ");
  Serial.println(concentration);

  delay(1000); // Wait for 1 second before reading again
}

• Inaccurate Readings: Ensure the sensor is calibrated correctly. Follow the calibration procedure provided by the manufacturer.
• No Readings: Check all connections and ensure the sensor is powered correctly.
• Drifting Readings: The sensor's membrane may be dirty or damaged. Clean the membrane gently with distilled water or replace it if necessary.

• Calibration: Perform calibration in a solution with a known oxygen concentration or in the air, as per the manufacturer's instructions.
• Connection Issues: Use a multimeter to check for continuity and correct voltage levels at the sensor's pins.
• Maintenance: Regularly inspect the sensor for any signs of damage or wear. Clean the sensor's membrane with care.

• Q: How often should the sensor be calibrated?

  • A: Calibration frequency depends on usage, but typically once before the first use and then every month or after any maintenance.

• Q: Can the sensor be used in saltwater?

  • A: Yes, the sensor can be used in saltwater, but ensure it is rinsed with fresh water after use to prevent corrosion.

• Q: What is the lifespan of the sensor?

  • A: With proper maintenance, the sensor can last for several years, but the membrane cap typically needs replacement every six months to a year.

Remember to refer to the manufacturer's datasheet and user manual for more detailed information and instructions.