Example Code for Arduino-Use UART to Read Gas Concentration

Hardware Preparation

• DFRuino UNO R3 x1
• DFR0784 Smart Gas Sensor Terminal x1
• Gas probe x1
• Jumper wires

Software Preparation

• Arduino IDE
• Download and install the DFRobot_GasSensor Library. (About how to install the library?)

Other Preparation Work

• Connect the module to the Arduino according to the connection diagram above. Of course, you can also use it with Gravity I/O Expansion Board to complete the project prototype more conveniently and quickly.
• Turn the selector switch on the sensor to the UART side.
• Download and install the DFRobot_GasSensor Library. (About how to install the library?)
• Open Arduino IDE and upload the following code to Arduino UNO.
• Open the serial port monitor of Arduino IDE, adjust the baud rate to 115200, and observe the serial port print result.

Sample Code

/*!
  * @file  readGasConcentration.ino
  * @brief Obtain the corresponding gas concentration in the current environment and output the concentration value
  * @n Experiment method: Connect the sensor communication pin to the main control and burn codes into it. 
  * @n Communication mode selection, dial switch SEL:0: IIC, 1: UART
    @n i2c address selection, the default i2c address is 0x77, A1 and A0 are combined into 4 types of IIC addresses
                | A1 | A0 |
                | 0  | 0  |    0x77
                | 0  | 1  |    0x76
                | 1  | 0  |    0x75
                | 1  | 1  |    0x74   default i2c address  
  * @n Experimental phenomenon: You can see the corresponding gas concentration value of the environment at this time by printing on the serial port
  * @copyright   Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
  * @licence     The MIT License (MIT)
  * @author      PengKaixing([email protected])
  * @version     V1.0
  * @date        2021-03-28
  * @get         from https://www.dfrobot.com
  * @url         https://github.com/dfrobot/DFRobot_GasSensor
  */
#include "DFRobot_GasSensor.h"
/*
//Enabled by default, use IIC communication at this time use UART communication when disabled
#define I2C_COMMUNICATION
#ifdef  I2C_COMMUNICATION
#define I2C_ADDRESS    0x77
  DFRobot_GAS_I2C gas(&Wire ,I2C_ADDRESS);
#else*/
#if (!defined ARDUINO_ESP32_DEV) && (!defined __SAMD21G18A__)
/**
  UNO:pin_2-----RX
      pin_3-----TX
*/
  SoftwareSerial mySerial(2,3);
  DFRobot_GAS_SoftWareUart gas(&mySerial);
#else
/**
  ESP32:IO16-----RX
        IO17-----TX
*/
  DFRobot_GAS_HardWareUart gas(&Serial2); //ESP32HardwareSerial
#endif
//#endif
void setup() {
/**
  Serial port initialization, used to view print output
*/
  Serial.begin(115200);
/**
  Sensor initialization, used to initialize the serial port or initialize the IIC, determined by the communication method used at the time
*/
  while(!gas.begin())
  {
    Serial.println("NO Deivces !");
    delay(1000);
  }
  Serial.println("The device is connected successfully!");
/**
  The data acquisition mode is: the main control needs to request data from the sensor
*/
  while (!gas.changeAcquireMode(gas.PASSIVITY))
  {
    delay(1000);
  }
  Serial.println("change acquire mode success!");
/**
  Turn on temperature compensation:gas.ON : Turn on
               gas.OFF：Turn off
*/
  gas.setTempCompensation(gas.ON);
/**
  Change the probe type to: O2
*/
  while (!gas.setGasType(gas.O2))
  {
    delay(1000);
  }
  Serial.println("change Gas Type success!");
}
void loop() {
/**
  Fill in the type of gas to be obtained in the readGasConcentration() parameter, and print
  Gas concentration at this time
  Print with 1s delay time each time
*/
  Serial.print("Ambient oxygen concentration is: ");
  Serial.print(gas.readGasConcentrationPPM(/*气体类型*/gas.O2));
  Serial.println(" %vol");
  Serial.println();
  delay(1000);
}

Result

Open the serial monitor, then you can get the corresponding gas concentration.

Note:
The product needs to be warmed up for more than 5 minutes when powered on for the first time, and it is recommended to warm up for more than 24 hours if it has not been used for a long time.

Additional Information

• The sample code uses an O2 probe. If you use other probes, you need to modify the detection gas type of the corresponding probe.