DFROBOT SEN0536 Gravity: SCD41红外CO2传感器产品资料使用教程

简介

Gravity: SCD41二氧化碳传感器，搭载了Sensirion公司新推出SCD41微型二氧化碳传感器传感器。该传感器基于光声传感原理以及Sensirion的PASens®和CMOSens® 专利技术，体积小巧，性能卓越。集成性价比极佳的湿度和温度传感器，实现片上信号补偿，并具备额外湿度和温度输出。 SCD41通过监测CO2分子吸收的能量测量CO2浓度。当发射红外脉冲时，CO2分子周期性的吸收红外线，这会引起额外的分子振动，从而会在腔内产生压力波。CO2浓度越高，吸收的光就越多，因此声波的振幅越大，通过内部麦克风测量、计算得出CO2浓度。

特性

CO2、温度、湿度三合一
体积小巧，仅32*27*8mm
功耗低，平均电流<4mA

应用场景

室内CO2浓度监测
大棚植物环境监测
新风系统环境检测

技术规格

供电电压：3.3V~5V
平均工作电流：<4mA
I2C地址：0x62
产品尺寸：32*27*8mm

二氧化碳

精确度：±(40 ppm + 5% MV)
测量范围：400 - 5000 ppm
响应时间：60S

湿度

典型相对湿度精度：6%RH
相对湿度测量范围：0 ~ 95%RH
响应时间：120S

温度

典型温度精度：0.8℃
温度测量范围：-10 ~ 60℃
响应时间：120S

引脚说明

序号	丝印	功能描述
1	VCC	电源正极
2	GND	电源负极
3	SCL	I2C时钟线
4	SDA	I2C数据线

Arduino使用教程

准备

硬件
- 1 x Arduino UNO控制板
- 1 x Gravity:SCD41二氧化碳传感器
- 若干杜邦线
软件
- Arduino IDE，点击下载Arduino IDE
- SCD41库文件和示例程序

关于如何安装库文件，点击链接

接线图

样例代码1 - 周期读取

循环读取SCD41数据

/*!
 * @file  periodMeasure.ino
 * @brief  This sample shows how to configure period measurement mode, compensation and calibration.
 * @note  The actual compensation and calibration parameter should be changed according to the operating environment
 * @copyright  Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
 * @license  The MIT License (MIT)
 * @author  [qsjhyy](yihuan.huang@dfrobot.com)
 * @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 set temperature offset
   * @details T(offset_actual) = T(SCD4X) - T(reference) + T(offset_previous)
   * @n T(offset_actual): the calculated actual temperature offset that is required
   * @n T(SCD4X): the temperature measured by the sensor (wait for a period of time to get steady readings)
   * @n T(reference): the standard reference value of the current ambient temperature
   * @n T(offset_previous): the previously set temperature offset
   * @n For example : 32(T(SCD4X)) - 30(T(reference)) + 2(T(offset_previous)) = 4(T(offset_actual))
   * @param tempComp - temperature offset value, unit ℃
   * @return None
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  SCD4X.setTempComp(4.0);

  /**
   * @brief get temperature offset
   * @return The current set temp compensation value, unit ℃
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  float temp = 0;
  temp = SCD4X.getTempComp();
  Serial.print("The current temperature compensation value : ");
  Serial.print(temp);
  Serial.println(" C");

  /**
   * @brief set sensor altitude
   * @param altitude - the current ambient altitude, unit m
   * @return None
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  SCD4X.setSensorAltitude(540);

  /**
   * @brief get sensor altitude
   * @return The current set ambient altitude, unit m
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  uint16_t altitude = 0;
  altitude = SCD4X.getSensorAltitude();
  Serial.print("Set the current environment altitude : ");
  Serial.print(altitude);
  Serial.println(" m");

  /**
   * @brief set automatic self calibration enabled
   * @param mode - automatic self-calibration mode:
   * @n       true : enable automatic self-calibration
   * @n       false : disable automatic self-calibration
   * @return None
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  // SCD4X.setAutoCalibMode(true);

  /**
   * @brief get automatic self calibration enabled
   * @return Automatic self-calibration mode:
   * @n        true : enable automatic self-calibration
   * @n        false : disable automatic self-calibration
   * @note When executing the command, the sensor can't be in period measurement mode
   */
  // if(SCD4X.getAutoCalibMode()) {
  //   Serial.println("Automatic calibration on!");
  // } else {
  //   Serial.println("Automatic calibration off!");
  // }

  /**
   * @brief persist settings
   * @details Configuration settings such as the temperature offset, sensor altitude and the ASC enabled/disabled 
   * @n  parameter are by default stored in the volatile memory (RAM) only and will be lost after a power-cycle.
   * @return None
   * @note To avoid unnecessary wear of the EEPROM, the persist_settings command should only be sent 
   * @n  when persistence is required and if actual changes to the configuration have been made. 
   * @n  The EEPROM is guaranteed to endure at least 2000 write cycles before failure.
   * @note Command execution time : 800 ms
   * @n When executing the command, the sensor can't be in period measurement mode
   */
  // SCD4X.persistSettings();

  /**
   * @brief reinit reinit
   * @details  The reinit command reinitializes the sensor by reloading user settings from EEPROM.
   * @return None
   * @note Before sending the reinit command, the stop measurement command must be issued.
   * @n  If the reinit command does not trigger the desired re-initialization, 
   * @n  a power-cycle should be applied to the SCD4x.
   * @n  Command execution time : 20 ms
   * @n When executing the command, the sensor can't be in period measurement mode
   */
  //SCD4X.moduleReinit();

  /**
   * @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 changing the sensor settings; after giving the stop_periodic_measurement command, the sensor needs to wait 500ms before responding to other commands.
   */
  SCD4X.enablePeriodMeasure(SCD4X_START_PERIODIC_MEASURE);

  Serial.println();
}

void loop()
{
  /**
   * @brief get data ready status
   * @return data ready status:
   * @n        true : data ready
   * @n        false : data not ready
   */
  if(SCD4X.getDataReadyStatus()) {
    /**
     * @brief set ambient pressure
     * @param ambientPressure - the current ambient pressure, unit Pa
     * @return None
     */
    // SCD4X.setAmbientPressure(96000);

    /**
     * @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.
     */
    DFRobot_SCD4X::sSensorMeasurement_t data;
    SCD4X.readMeasurement(&data);

    Serial.print("Carbon dioxide concentration : ");
    Serial.print(data.CO2ppm);
    Serial.println(" ppm");

    Serial.print("Environment temperature : ");
    Serial.print(data.temp);
    Serial.println(" C");

    Serial.print("Relative humidity : ");
    Serial.print(data.humidity);
    Serial.println(" RH");

    Serial.println();
  }
  delay(1000);
}

结果

样例代码2 - 单次测量

休眠醒来后读取数据，然后再休眠

/*!
 * @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](yihuan.huang@dfrobot.com)
 * @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
}

结果

主要API接口函数列表

/**
   * @fn enablePeriodMeasure
   * @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 在对传感器进行设置的时候，必须停止测量模式； 且在发出stop_periodic_measurement命令后，传感器等待500ms后才响应其他命令。
   */
  void enablePeriodMeasure(uint16_t mode);

  /**
   * @fn readMeasurement
   * @brief 读取测量数据
   * @param data - sSensorMeasurement_t, 传感器测量值，包含CO2浓度(ppm)、温度(C)、湿度(RH)
   * @return None
   * @note CO2测量范围: 0~40000 ppm; 温度测量范围: -10~60 C; 湿度测量范围: 0~100 %RH.
   */
  void readMeasurement(sSensorMeasurement_t * data);

  /**
   * @fn getDataReadyStatus
   * @brief get data ready status
   * @return data ready status:
   * @n        true : data ready
   * @n        false : data not ready
   */
  bool getDataReadyStatus(void);

树莓派使用教程

准备

硬件
- 树莓派4代B型（或类似）主控板 x 1
- Gravity:SCD41二氧化碳传感器 x 1
- 若干杜邦线 x 1
软件
- SCD41二氧化碳传感器python库
- RASPBIAN树莓派官方操作系统

接线图

将模块与树莓派按照连线图相连。I2C地址为0x62

安装驱动

启动树莓派的I2C接口。如已开启，可跳过该步骤。打开终端（Terminal），键入如下指令，并回车：
pi@raspberrypi:~ $ sudo raspi-config
然后用上下键选择“ 5 Interfacing Options ”, 按回车进入，选择 “ P5 I2C ”, 按回车确认“ YES ”即可。重启树莓派主控板。
安装Python依赖库与git，树莓派需要联网。如已安装，可跳过该步骤。在终端中，依次键入如下指令，并回车：
pi@raspberrypi:~ $ sudo apt-get update
pi@raspberrypi:~ $ sudo apt-get install build-essential python-dev python-smbus git
下载DFRobot_SCD4X驱动库。在终端中，依次键入如下指令，并回车： pi@raspberrypi:~ $ cd Desktop/
pi@raspberrypi:~/Desktop $ git clone https://github.com/dfrobot/DFRobot_SCD4X

样例代码1-连续测量(period_measure.py)

在终端中，键入如下指令并回车，运行样例代码：
pi@raspberrypi:~/Desktop $ cd DFRobot_SCD4X/python/raspberrypi/examples/
pi@raspberrypi:~/Desktop/DFRobot_SCD4X/python/raspberrypi/examples/ $ python period_measure.py

样例代码2-单次测量(single_shot_measure.py)

在终端中，键入如下指令并回车，运行样例代码：
pi@raspberrypi:~/Desktop $ cd DFRobot_SCD4X/python/raspberrypi/examples/
pi@raspberrypi:~/Desktop/DFRobot_SCD4X/python/raspberrypi/examples/ $ python single_shot_measure.py

Mind+使用教程

说明

使用Mind+1.7.3及以上版本，打开扩展，在用户库中粘贴库链接加载用户库。

scd4xco2模块Mind+库：https://gitee.com/dfjoannali/ext-scd4xco2

程序示例

Arduino模式uno：
Python模式行空板：

常见问题

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