How to Use Electrochemical Ozone / O3 Sensor (0-10 ppm, I2C): Examples, Pinouts, and Specs

The Gravity Electrochemical Ozone Sensor (SEN0321) is a high-precision sensor designed to measure ozone (O3) concentration in the air. It operates within a range of 0 to 10 ppm and communicates via the I2C protocol, making it easy to integrate into microcontroller-based systems. This sensor is ideal for applications requiring accurate ozone monitoring, such as environmental monitoring, industrial safety, and air quality control.

• Air quality monitoring systems
• Industrial safety and hazard detection
• Environmental research and analysis
• Smart home and IoT devices for pollution detection

The following table outlines the key technical details of the Gravity Electrochemical Ozone Sensor:

The sensor has a 4-pin interface for power and communication. The pinout is as follows:

1. Power Supply: Connect the VCC pin to a 3.3V or 5V power source and the GND pin to ground.
2. I2C Communication: Connect the SDA and SCL pins to the corresponding I2C pins on your microcontroller (e.g., Arduino UNO: A4 for SDA, A5 for SCL).
3. Pull-Up Resistors: Ensure that the I2C bus has pull-up resistors (typically 4.7kΩ) on the SDA and SCL lines if not already present.

Below is an example of how to interface the sensor with an Arduino UNO to read ozone concentration:

#include <Wire.h>

// I2C address of the Ozone Sensor
#define OZONE_SENSOR_ADDR 0x73

void setup() {
  Serial.begin(9600); // Initialize serial communication
  Wire.begin();       // Initialize I2C communication
  Serial.println("Ozone Sensor Initialization...");
}

void loop() {
  float ozoneConcentration = readOzoneConcentration();
  if (ozoneConcentration >= 0) {
    Serial.print("Ozone Concentration: ");
    Serial.print(ozoneConcentration);
    Serial.println(" ppm");
  } else {
    Serial.println("Error reading ozone concentration.");
  }
  delay(1000); // Wait 1 second before the next reading
}

// Function to read ozone concentration from the sensor
float readOzoneConcentration() {
  Wire.beginTransmission(OZONE_SENSOR_ADDR);
  Wire.write(0x03); // Command to request ozone concentration
  if (Wire.endTransmission() != 0) {
    return -1; // Return error if communication fails
  }

  delay(100); // Wait for the sensor to process the request

  Wire.requestFrom(OZONE_SENSOR_ADDR, 2); // Request 2 bytes of data
  if (Wire.available() == 2) {
    uint8_t highByte = Wire.read(); // Read the high byte
    uint8_t lowByte = Wire.read();  // Read the low byte
    return ((highByte << 8) | lowByte) / 100.0; // Convert to ppm
  } else {
    return -1; // Return error if data is unavailable
  }
}

• Warm-Up Time: Allow the sensor to warm up for at least 5 minutes after powering on for accurate readings.
• Calibration: The sensor is factory-calibrated, but periodic calibration may be required for long-term accuracy.
• Environmental Conditions: Avoid exposing the sensor to extreme temperatures, humidity, or corrosive gases, as these can affect its performance and lifespan.
• I2C Address Conflicts: If multiple I2C devices are connected, ensure that their addresses do not conflict. The default address of this sensor is 0x73.

1. No Data from Sensor

   • Cause: Incorrect wiring or I2C address mismatch.
   • Solution: Verify the connections and ensure the I2C address in the code matches the sensor's address.

2. Inaccurate Readings

   • Cause: Insufficient warm-up time or environmental interference.
   • Solution: Allow the sensor to warm up for at least 5 minutes and ensure it is used in a stable environment.

3. I2C Communication Errors

   • Cause: Missing pull-up resistors or incorrect I2C pin connections.
   • Solution: Add 4.7kΩ pull-up resistors to the SDA and SCL lines if not already present. Double-check the wiring.

4. Sensor Not Detected

   • Cause: Faulty sensor or incorrect power supply voltage.
   • Solution: Ensure the sensor is powered with 3.3V to 5.5V and check for physical damage.

Q1: Can this sensor detect ozone concentrations above 10 ppm?
No, the sensor is designed to measure ozone concentrations within the range of 0 to 10 ppm. Exceeding this range may damage the sensor or result in inaccurate readings.

Q2: How often should the sensor be calibrated?
Under normal conditions, the sensor does not require frequent calibration. However, for critical applications, calibration every 6 months is recommended.

Q3: Can this sensor be used outdoors?
Yes, but it should be protected from direct exposure to rain, extreme temperatures, and high humidity to ensure reliable operation.

Q4: Is the sensor compatible with 3.3V microcontrollers?
Yes, the sensor operates with both 3.3V and 5V logic levels, making it compatible with a wide range of microcontrollers.

By following this documentation, users can effectively integrate and utilize the Gravity Electrochemical Ozone Sensor (SEN0321) in their projects.