DFRobot_MHZ9041A

• 中文版 The MH-Z9041A Laser Methane Gas Sensor is a household-type methane sensor that utilizes Tunable Diode Laser Absorption Spectroscopy (TDLAS) for methane gas detection. It features a dual-pass optical path structure, offering excellent gas selectivity, no dependence on oxygen, and a long service life.

Equipped with built-in temperature control and compensation algorithms, the sensor achieves accurate methane concentration measurement. It also provides a serial output interface, making it easy to use and integrate.

This sensor combines mature laser gas absorption detection technology with a stable optical design and precise circuit engineering, resulting in a high-performance gas sensor.

Product Link(https://www.dfrobot.com)

SKU：SEN0654

Table of Contents

• Summary
• Installation
• Methods
• Compatibility
• History
• Credits

Summary

Provide an Arduino library for the ch4 module with the following features: Obtain the methane concentration

Installation

There are two methods for using this library:

1. Open Arduino IDE, search for "DFRobot_MHZ9041A" on the status bar in Tools ->Manager Libraries and install the library.
   
2. Download the library file before use, paste it into \Arduino\libraries directory, then open the examples folder and run the demo in the folder.
   

Methods

/**
 * @enum eFaultCode_t
 * @brief Types of sensor fault codes
 */
typedef enum {
  eSensorNormal = 0x00,                   // 00 Sensor operating normally
  eTempControlError = 0x01,               // 01 Temperature control error
  eAmbientTempError = 0x02,               // 02 Ambient temperature error
  eAmbientAndTempControlError = 0x03,     // 03 Ambient temperature error & temperature control error
  eLaserSignalWeak = 0x04,                // 04 Weak laser signal
  eAmbientAndSignalWeakError = 0x06,      // 06 Ambient temperature error & weak laser signal
  eLaserSignalError = 0x10,               // 16 Laser signal error
  eAmbientAndSignalError = 0x12,          // 18 Ambient temperature error & laser signal error
} eFaultCode_t;

/**
 * @enum eModuleMode_t
 * @brief sensor work mode
 */
typedef enum {
  ePassivityMode = 0x00,
  eActiveMode = 0x01,
} eWorkMode_t;

/**
 * @fn setMode
 * @brief Set the working mode
 * @param mode Working mode
 * @note 0x00: Active mode, 0x01: Passive mode
 * @return null
 */
void setMode(eWorkMode_t mode);

/**
 * @fn getSourceData
 * @brief Get raw sensor data
 * @return Raw data string, up to 43 bytes in length
 */
String getSourceData(void);

/**
 * @fn getCH4Concentration
 * @brief Get methane (CH4) concentration
 * @return CH4 concentration value, two decimal places, the second digit is always 0, unit: %LEL
 */
float getCH4Concentration(void);

/**
 * @fn getTemperature
 * @brief Get ambient temperature
 * @return Temperature in degrees Celsius
 */
float getTemperature(void);

/**
 * @fn getErrorMsg
 * @brief Get error code information
 * @return Error code
 */
eFaultCode_t getErrorMsg(void);

/**
 * @fn getActiveData
 * @brief Get raw data in active reporting mode
 * @return Raw data string in active mode
 */
String getActiveData(void);

/**
 * @fn reset
 * @brief Reset the onboard methane sensor; hold the reset pin low for 2 seconds to complete the reset
 * @return null
 */
void reset(void);

/**
 * @fn setDeviceID
 * @brief Set the module address,range 0x03~0x7F
 * @return Returns 1 if successful, otherwise returns 0
 */
bool setDeviceID(uint8_t id);

/**
 * @fn getDeviceID
 * @brief Get the module address
 * @return Module address
 */
uint8_t getDeviceID(void);

/**
 * @fn setBaud
 * @brief Set the Baud object
 * @param baud eModuleBaud_t
 * @note
 * | Support Baud | UNO/ESP8266 | Leonardo/Mega2560 | ESP32 |  M0 |
 * | eBaud9600    |      √      |         √         |   √   |  √  |
 * | eBaud19200   |      √      |         √         |   √   |  √  |
 * | eBaud38400   |      √      |         √         |   √   |  √  |
 * | eBaud57600   |      √      |         √         |   √   |  √  |
 * | eBaud115200  |             |         √         |   √   |  √  |
 */
void setBaud(eModuleBaud_t baud);

/**
 * @fn getBaud
 * @brief Get the Baud object
 * @return baud rate
 * @note 9600, 19200, 38400, 57600, 115200
 */
uint32_t getBaud(void);

Compatibility

MCU	Work Well	Work Wrong	Untested	Remarks
Arduino Uno	√
Arduino MEGA2560	√
Arduino Leonardo	√
FireBeetle-ESP8266	√
FireBeetle-ESP32	√
FireBeetle-M0	√
Micro:bit	√	nonsupport uart

History

• 2025/03/26 - Version V0.1.0 released.

Credits

Written by ZhixinLiu(zhixin.liu@dfrobot.com), 2025. (Welcome to our website)