Example Code for Arduino-Single Measurement

Hardware Preparation

• DFRduino UNO R3 (or similar) × 1
• Gravity: SCD41 Infrared CO2 Sensor - I2C × 1
• M-M/F-M/F-F Jumper wires

Software Preparation

• Arduino IDE
• Download and install the SCD4X Library. (About how to install the library?)

Wiring Diagram

Other Preparation Work

The first set of data obtained after waking up is invalid and should be discarded (as indicated by the chip datasheet).

Sample Code

/*!
 * @file  singleShotMeasure.ino
 * @brief  This sample shows how to set single measurement mode, perform reset operation, and set sleep and wake-up mode.
 * @details Get 6 data from single measurement, take the average value, print it, enter sleep mode, wake up the sensor after 5 minutes, and repeat the above measurement process
 * @copyright  Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
 * @license  The MIT License (MIT)
 * @author  [qsjhyy]([email protected])
 * @version  V1.0
 * @date  2022-05-11
 * @url  https://github.com/DFRobot/DFRobot_SCD4X
 */
#include <DFRobot_SCD4X.h>

/**
 * @brief Constructor
 * @param pWire - Wire object is defined in Wire.h, so just use &Wire and the methods in Wire can be pointed to and used
 * @param i2cAddr - SCD4X I2C address.
 */
DFRobot_SCD4X SCD4X(&Wire, /*i2cAddr = */SCD4X_I2C_ADDR);

void setup(void)
{
  Serial.begin(115200);

  // Init the sensor
  while( !SCD4X.begin() ){
    Serial.println("Communication with device failed, please check connection");
    delay(3000);
  }
  Serial.println("Begin ok!");

  /**
   * @brief set periodic measurement mode
   * @param mode - periodic measurement mode:
   * @n       SCD4X_START_PERIODIC_MEASURE : start periodic measurement, signal update interval is 5 seconds.
   * @n       SCD4X_STOP_PERIODIC_MEASURE : stop periodic measurement command
   * @n       SCD4X_START_LOW_POWER_MEASURE :  start low power periodic measurement, signal update interval is approximately 30 seconds.
   * @return None
   * @note The measurement mode must be disabled when configuring the sensor; after giving the stop_periodic_measurement command, the sensor needs to wait 500ms before responding to other commands.
   */
  SCD4X.enablePeriodMeasure(SCD4X_STOP_PERIODIC_MEASURE);

  /**
   * @brief perform self test
   * @details The perform_self_test feature can be used as an end-of-line test to check sensor 
   * @n  functionality and the customer power supply to the sensor.
   * @return module status:
   * @n        0 : no malfunction detected
   * @n        other : malfunction detected
   * @note Command execution time : 10000 ms
   * @n When executing the command, the sensor can't be in period measurement mode.
   */
  if(0 != SCD4X.performSelfTest()) {
    Serial.println("Malfunction detected!");
  }

  Serial.println();
}

void loop()
{
  /**
   * @brief Set the sensor as sleep or wake-up mode (SCD41 only)
   * @param mode - Sleep and wake-up mode:
   * @n       SCD4X_POWER_DOWN : Put the sensor from idle to sleep to reduce current consumption.
   * @n       SCD4X_WAKE_UP : Wake up the sensor from sleep mode into idle mode.
   * @return None
   * @note Note that the SCD4x does not acknowledge the wake_up command. Command execution time : 20 ms
   * @n When executing the command, the sensor can't be in period measurement mode.
   */
  Serial.print("Waking sensor...");
  SCD4X.setSleepMode(SCD4X_WAKE_UP);

  DFRobot_SCD4X::sSensorMeasurement_t data[6];
  memset(data, 0, sizeof(data));
  uint32_t averageCO2ppm=0;
  float averageTemp=0.0, averageHumidity=0.0;
  Serial.print("Measuring...");
  for(uint8_t i=0; i<6; i++) {
    /**
     * @brief measure single shot（SCD41 only）
     * @details  On-demand measurement of CO2 concentration, relative humidity and temperature.
     * @n  Get the measured data through readMeasurement(sSensorMeasurement_t data) interface
     * @param mode - Single-measurement mode:
     * @n       SCD4X_MEASURE_SINGLE_SHOT : On-demand measurement of CO2 concentration, relative humidity and temperature. 
     * @n                                   Max command duration 5000 [ms].
     * @n       SCD4X_MEASURE_SINGLE_SHOT_RHT_ONLY : On-demand measurement of relative humidity and temperature only.
     * @n                                            Max command duration 50 [ms].
     * @note In SCD4X_MEASURE_SINGLE_SHOT_RHT_ONLY mode, CO2 output is returned as 0 ppm.
     * @return None
     * @note When executing the command, the sensor can't be in period measurement mode.
     */
    SCD4X.measureSingleShot(SCD4X_MEASURE_SINGLE_SHOT);

    /**
     * @brief get data ready status
     * @return data ready status:
     * @n        true : data ready
     * @n        false : data not ready
     */
    while(!SCD4X.getDataReadyStatus()) {
      delay(100);
    }

    /**
     * @brief Read the measured data
     * @param data - sSensorMeasurement_t, the values measured by the sensor, including CO2 concentration (ppm), temperature (℃) and humidity (RH)
     * @n  typedef struct {
     * @n    uint16_t   CO2ppm;
     * @n    float   temp;
     * @n    float   humidity;
     * @n  } sSensorMeasurement_t;
     * @return None
     * @note CO2 measurement range: 0~40000 ppm; temperature measurement range: -10~60 ℃; humidity measurement range: 0~100 %RH.
     */
    SCD4X.readMeasurement(&data[i]);
    if(0 != i) {   // Discard the first set of data, because the chip datasheet indicates the first reading obtained after waking up is invalid
      averageCO2ppm += data[i].CO2ppm;
      averageTemp += data[i].temp;
      averageHumidity += data[i].humidity;
    }
    Serial.print(i);
  }
  Serial.print("\nCarbon dioxide concentration : ");
  Serial.print(averageCO2ppm / 5);
  Serial.println(" ppm");

  Serial.print("Environment temperature : ");
  Serial.print(averageTemp / 5);
  Serial.println(" C");

  Serial.print("Relative humidity : ");
  Serial.print(averageHumidity / 5);
  Serial.println(" RH\n");

  // Put the sensor from idle to sleep to reduce current consumption.
  Serial.print("Sleeping sensor...");
  SCD4X.setSleepMode(SCD4X_POWER_DOWN);
  delay(300000);   // Wake up the sensor after 5 minutes, and repeat the above measurement process
}

Result