The Winsen MH-Z19B CO₂ sensor manual provides specifications, wiring, UART commands, calibration methods and safety guidelines.
This manual describes the MH‑Z19B non‑dispersive infrared (NDIR) CO₂ sensor, its features, technical specifications and recommended applications such as HVAC, air‑quality monitoring and smart home devices. It includes detailed pin definitions, output options (UART, analog, PWM) and wiring instructions.
The document also explains how to perform zero‑point and span calibrations manually or via UART commands, outlines UART communication settings, and lists safety and handling precautions to ensure reliable long‑term operation. This manual is written in Chinese.
| Supply voltage | 4.5 – 5.5 V DC |
|---|---|
| Average current | <20 mA @5 V |
| Peak current | 150 mA @5 V |
| Interface voltage level | 3.3 V (compatible with 5 V) |
| Measurement range | 0 – 10 000 ppm (selectable) |
| Output signals | UART (TTL 3.3 V), PWM, Analog (0.4–2 V default) |
| Pre‑heat time | 3 min |
| Response time | <120 s |
| Operating temperature | 0 – 50 °C |
| Operating humidity | 0 – 95 % RH (no condensation) |
The sensor offers three output options: a UART (TTL) serial interface, an analog voltage output (0.4–2 V default, configurable to 0–3 V), and a PWM signal.
The sensor should be kept in a well‑ventilated space, away from heat sources and direct sunlight, with supply voltage between 4.5 V and 5.5 V and a minimum current of 150 mA.