The Gravity: I2C Oxygen Sensor is based on electrochemical principles and it can measure the ambient O2 concentration accurately and conveniently. With high anti-interference ability, high stablility and high sensitivity, this arduino-compatible oxygen sensor can be widely applied to fields like portable device, air quality monitoring device, and industries, mines, warehouses and other spaces where air is not easy to circulate.

This compact dfrobot oxygen sensor supports I2C output, it can be calibrated in the air, can accurately measure the oxygen concentration in the environmentit. It is compatible with many mainboards like Arduino Uno, esp32, Raspberry Pi and so on. Its effective range is 0~25%Vol, and resolution can reach to 0.15%Vol. It supports wide range input voltage: 3.3V to 5.5V. Moreover, the lifetime is as long as 2 years. With simple Gravity interface and practical sample code, you can build your own oxygen concentration monitor easily and conveniently.




Board Overview

Num Label Description
1 SDA I2C System Data Line
2 SCL I2C System Clock Line
3 GND -
4 VCC +


Download the program to Arduino UNO and open the serial monitor to check the O2 concentration.


Connection Diagram

Sample Code

1.According to the connection diagram to connect the module to Arduino UNO. In default, the I2C address is 0x73 which corresponds to the ADDRESS_3 in the code. If you want to modify the I2C address, please configure the hardware I2C address by the dial switch and modify the IIC address part: ADDRESS_X in the sample code. The relationship between the dial switch and I2C address is shown as below:

2.Download and install the DFRobot_OxygenSensor Library (About how to install the library?)

3.Open Arduino IDE and upload the code below to Arduino UNO.

4.Open the Arduino IDE's serial monitor, adjust the baud rate to 9600, and observe the serial print results.

  * @file  ReadOxygenData.ino
  * @brief Read oxygen concentration ,The unit is concentration percent (% vol).
  * @n step: we must first determine the iic device address, will dial the code switch A0, A1 (ADDRESS_0 for [0 0]), (ADDRESS_1 for [1 0]), (ADDRESS_2 for [0 1]), (ADDRESS_3 for [1 1]).
  * @n       And then read the data.
  * @n note: it takes time to stable oxygen concentration, about 8 minutes.
  * @n The experimental phenomenon is that a certain percentage of oxygen concentration is printed on the serial port.
  * @n Because the oxygen concentration in oxygen air is certain, the data will not be greater than 25% vol.
  * @copyright   Copyright (c) 2010 DFRobot Co.Ltd (
  * @licence     The MIT License (MIT)
  * @author      ZhixinLiu(
  * @version     V0.2
  * @date        2019-10-10
  * @get         from
  * @url   */
#include "DFRobot_OxygenSensor.h"

#define COLLECT_NUMBER    10             // collect number, the collection range is 1-100.
#define Oxygen_IICAddress ADDRESS_3
/*   iic slave Address, The default is ADDRESS_3.
       ADDRESS_0               0x70      // iic device address.
       ADDRESS_1               0x71
       ADDRESS_2               0x72
       ADDRESS_3               0x73

DFRobot_OxygenSensor Oxygen;
void setup() 
  while(!Oxygen.begin(Oxygen_IICAddress)) {
    Serial.println("I2c device number error !");
  Serial.println("I2c connect success !");

void loop()
  float oxygenData = Oxygen.ReadOxygenData(COLLECT_NUMBER);
  Serial.print(" Oxygen concentration is ");
  Serial.println(" %vol");

Expected Results

Turn on the serial monitor and heat it up for about 3 minutes to get the final data. (Test environment: closed environment with ozone generator)

Gravity:I2C Oxygen Sensor Result


The oxygen sensor can be calibrated using the characteristic that the oxygen content in the atmosphere is 20.9%.

Calibration Method:Place the oxygen sensor in the outdoor environment, after the sensor data is stable, long press the calibration button on the sensor for 2 seconds, the sensor will be calibrated.


For any questions, advice or cool ideas to share, please visit the DFRobot Forum.

More Documents

DFshopping_car1.png Get Gravity: I2C Oxygen Sensor (0-25%Vol) from DFRobot Store or DFRobot Distributor.

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