DFRobot_SCD4X
The SCD4x(SCD40/SCD41) is Sensirion’s next generation miniature CO2 sensor. This sensor builds on the photoacoustic sensing principle and Sensirion’s patented PAsens® and CMOSens® technology to offer high accuracy at an unmatched price and smallest form factor. SMD assembly allows cost- and space-effective integration of the sensor combined with maximal freedom of design. On-chip signal compensation is realized with the build-in SHT4x humidity and temperature sensor. CO2 is a key indicator for indoor air quality as high levels compromise humans’ cognitive low power and well-being. The SCD4x enables smart ventilation systems to regulate ventilation in the most energy-efficient and human-friendly way. Moreover, indoor air quality monitors and other connected devices based on the SCD4x can help maintaining low CO2 concentration for a healthy, productive environment.
Product Link (https://www.dfrobot.com/product-2646.html)
SKU: SEN0536Table of Contents
Summary
- Photoacoustic sensor technology PASens®
- Large output range: 0 ppm – 40’000 ppm
- Large supply voltage range: 2.4 – 5.5 V
- High accuracy: ±(40 ppm + 5 %)
- Digital I2C interface
- Integrated temperature and humidity sensor
- Low power operation down to < 0.4 mA avg. @ 5 V, 1 meas. / 5 minutes
Installation
There two methods:
- To use this library, first download the library file, paste it into the \Arduino\libraries directory, then open the examples folder and run the demo in the folder.
- Search the DFRobot_SCD4X library from the Arduino Software Library Manager and download it.
Methods
/**************************** Init and reset ********************************/
/**
* @fn DFRobot_SCD4X
* @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.
* @return None
*/
DFRobot_SCD4X(TwoWire *pWire=&Wire, uint8_t i2cAddr=SCD4X_I2C_ADDR);
/**
* @fn begin
* @brief Init function
* @return bool type, true if successful, false if error
*/
bool begin(void);
/**
* @fn setSleepMode
* @brief set the sensor as sleep or wake-up mode (SCD41 only)
* @param mode - 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 this function, the sensor can't be in period measurement mode.
*/
void setSleepMode(uint16_t mode);
/**
* @fn performSelfTest
* @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.
*/
uint16_t performSelfTest(void);
/**
* @fn moduleReinit
* @brief module 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.
*/
void moduleReinit(void);
/**
* @fn performFactoryReset
* @brief perform factory reset
* @details The perform_factory_reset command resets all configuration settings stored
* @n in the EEPROM and erases the FRC and ASC algorithm history.
* @return None
* @note Command execution time : 1200 ms
* @n When executing the command, the sensor can't be in period measurement mode.
*/
void performFactoryReset(void);
/********************************* Measurement Function *************************************/
/**
* @fn measureSingleShot
* @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 - * @n 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].
* @return None
* @note In SCD4X_MEASURE_SINGLE_SHOT_RHT_ONLY mode, CO2 output is returned as 0 ppm.
* @n When executing the command, the sensor can't be in period measurement mode.
*/
void measureSingleShot(uint16_t mode);
/**
* @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 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.
*/
void enablePeriodMeasure(uint16_t mode);
/**
* @fn readMeasurement
* @brief Read the measured data
* @param data - sSensorMeasurement_t, the values measured by the sensor, including CO2 concentration (ppm), temperature (℃), humidity (RH)
* @return None
* @note CO2 measurement range: 0~40000 ppm; temperature measurement range: -10~60 ℃; humidity measurement range: 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);
/*************************** compensation and calibration ********************************/
/**
* @fn setTempComp
* @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 temperature standard reference value of the current ambient
* @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
*/
void setTempComp(float tempComp);
/**
* @fn getTempComp
* @brief get temperature offset
* @return The current temp compensation value, unit ℃
* @note When executing the command, the sensor can't be in period measurement mode
*/
float getTempComp(void);
/**
* @fn setSensorAltitude
* @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
*/
void setSensorAltitude(uint16_t altitude);
/**
* @fn getSensorAltitude
* @brief get sensor altitude
* @return The current ambient altitude, unit m
* @note When executing the command, the sensor can't be in period measurement mode
*/
uint16_t getSensorAltitude(void);
/**
* @fn setAmbientPressure
* @brief set ambient pressure
* @param ambientPressure - the current ambient pressure, unit Pa
* @return None
*/
void setAmbientPressure(uint32_t ambientPressure);
/**
* @fn setAutoCalibMode
* @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
*/
void setAutoCalibMode(bool mode);
/**
* @fn getAutoCalibMode
* @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
*/
bool getAutoCalibMode(void);
/**
* @fn persistSettings
* @brief Save the settings into EEPROM, default to be in RAM
* @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.
* @n Command execution time : 800 ms
* @n When executing the command, the sensor can't be in period measurement mode
*/
void persistSettings(void);
Compatibility
| MCU | Work Well | Work Wrong | Untested | Remarks |
|---|---|---|---|---|
| Arduino Uno | √ | |||
| Arduino MEGA2560 | √ | |||
| Arduino Leonardo | √ | |||
| FireBeetle-ESP8266 | √ | |||
| FireBeetle-ESP32 | √ | |||
| FireBeetle-M0 | √ | |||
| Micro:bit | √ |
History
- 2022/05/11 - Version 1.0.0 released.
- 2022/12/13 - Version 1.0.1 released.
Credits
Written by qsjhyy(yihuan.huang@dfrobot.com), 2022. (Welcome to our website)