ChipScout

Sensors

MH-Z19B

NDIR CO2 sensor module commonly used in indoor air quality projects.

China-madeWinsenActiveModerate

Best For

Projects needing CO2 and NDIR with a commonly available sensors part.

Avoid If

You need production-grade certainty without checking the exact module vendor, pinout, and library maintenance status.

Quick Decision Notes

MH-Z19B is indexed as a sensors part from Winsen. ChipScout tracks it by practical maker-facing dimensions: interfaces, library readiness, estimated price, field-level sources, and whether the page is strong enough for selection rather than only lookup.

Technical Specifications

MeasurementCO2Source: Winsen
InterfaceUART / PWMSource: Winsen
Range0 - 5000ppm commonSource: Winsen
Working Voltage5VSource: Winsen

Common Use Cases

  • Maker prototypes
  • Low-cost modules
  • Educational hardware

Known Issues

  • Breakout boards may use different pin labels or regulator choices
  • Clone modules can differ from the original datasheet part

Interfaces and Library Support

Interfaces
UARTPWM
Wireless
None
Voltage
3.3V
Libraries
Arduino verifiedMicroPython pending
Data Integrity80% confidence
Sourcehttps://www.winsen-sensor.com/
Last verified2026-05-20
Core specsVerified
PinoutAvailable
Library supportChecked
Price rangePresent
Found a wrong spec?

Every field is meant to be source-backed. Corrections should include a datasheet URL, vendor page, module photo, or reproducible library test.

Submit correction

Source Resources

Datasheethttps://www.winsen-sensor.com/WinsenLibraryMH-Z19B Arduino library lookupArduino

Pinout Table

VCC3.3VPower the module from a rail that matches the breakout board, not just the bare IC.
GNDCommon groundConnect ground between the controller, sensor/module, and external power supply.
TXMCU RXCross TX to RX between the module and controller.
RXMCU TXCheck whether the module is 3.3V logic before connecting to 5V boards.

Pinout is not yet source-verified. Use the table as an integration checklist, then confirm exact pins against the module vendor page before wiring hardware.

Common Wiring

VCC

Power the module from a rail that matches the breakout board, not just the bare IC.

GND

Connect ground between the controller, sensor/module, and external power supply.

TX

Cross TX to RX between the module and controller.

RX

Check whether the module is 3.3V logic before connecting to 5V boards.

Arduino Example

void setup() {
  Serial.begin(115200);
  Serial.println("MH-Z19B GPIO wiring smoke test");
}

void loop() {
  // Replace with the maintained MH-Z19B library or module protocol.
  Serial.println("Read or toggle the connected signal pin.");
  delay(1000);
}
MH-Z19B Arduino library lookup

MicroPython Example

MicroPython support is pending. Treat community scripts as prototypes until a maintained driver is linked and tested on a known development board.

Recommended Development Boards

ESP32-C3 development board

Low-cost Wi-Fi/BLE board with enough interfaces for most sensors and modules.

Arduino Uno R4 / compatible

Good baseline for beginner wiring and library validation.

Raspberry Pi Pico W

Practical MicroPython target for I2C, SPI, UART, PWM, and ADC experiments.

Alternative Model Reasons

ACS712SensorsCompare this option when price or module availability is the deciding constraint.
ADXL345SensorsChoose this when MicroPython support is required for fast prototyping.
AHT10SensorsChoose this when MicroPython support is required for fast prototyping.
AHT20SensorsChoose this when MicroPython support is required for fast prototyping.

Common Questions

What is MH-Z19B best used for?

Projects needing CO2 and NDIR with a commonly available sensors part.

Does MH-Z19B support Arduino or MicroPython?

MH-Z19B has verified Arduino support and MicroPython support pending verification.

What interfaces does MH-Z19B use?

MH-Z19B lists UART, PWM; wireless support is no wireless protocol.

Compare MH-Z19B vs ACS712

Alternatives and Related Parts

ACS712

Allegro MicroSystems

Hall-effect current sensor module used for AC/DC current measurement projects.

China-madeSensors76% confidence

ADXL345

Analog Devices

3-axis digital accelerometer with broad maker library support.

China-madeSensors84% confidence

AHT10

Aosong

I2C temperature and humidity sensor commonly sold as a compact low-cost breakout.

China-madeSensors76% confidence

AHT20

Aosong

Popular Chinese I2C temperature and humidity sensor used as a low-cost SHT-series alternative.

China-madeSensors82% confidence