MH-Z19C Infrared Sensor module 5000ppm CO2 monitor HVAC PWM output UART

CO2 sensor model MH-Z19C. High precision working voltage 5.0±0.1V DC. The measuring range is between 0 and 5000 ppm. It has a low power consumption. UART and PWM output.

The infrared gas module is a common type, small size sensor, using non-dispersive infrared (NDIR) principle to detect the existence of CO2 in the air, with good selectivity, non-oxygen dependent and long life.

Specifications:

• New and high quality
• Model No. MH-Z19C
• Detection Gas CO2
• Working voltage 5.0±0.1V DC
• Average current < 40mA (@5V power supply)
• Peak current 125mA (@5V power supply)
• Interface level 3.3 V (Compatible with 5V)
• Detection Range 0~5000ppm(optional) ± (50ppm+5% reading value)
• Output signal: Serial Port (UART) (TTL level 3.3V) /PWM
• Preheat time 1 min
• Response Time T90 < 120 s
• Working temperature -10 ~ 50 ℃
• Working humidity 0 ~ 95% RH (No condensation)
• Weight 5 g
• Lifespan > 5 years
• Color: Gold
• Size (L * W * H): Approx. 33 x 20 x 9 mm

Applications

• HVAC cooling 
• Air cleaning device 
• Indoor air quality monitoring
• Intelligent house 
• Ventilation system 
• Schools, colleges, etc.

MH-Z19C Infrared Sensor module 5000ppm CO2 monitor HVAC PWM output UART features:

-High sensitivity, high resolution
-Output modes: UART and PWM wave
- Interference by anti-water vapor. No poisoning
- Temperature compensation, excellent linear output
- Low power consumption, good stability and long service life
-It is widely used in HVAC refrigeration and quality monitoring of the indoor air

Power supply

A power supply of between 4.9 volts and 5.1 volts (a very narrow range) must be available from a USB port for it to work.

Before connecting the sensor, you must have a multimeter:

If you measure with the multimeter on the Vin pin and see that the voltage is too high, simply find another power supply that puts out a lower voltage (you're bound to have an old one). Plug it in, and measure again.

If the voltage is too low, you can do two things:

• Find a power supply that puts out a higher voltage.
• Jumper the Schottky diode with a jumper wire (or remove it from the board and jumper it).

Note: Check if your board has a VU pin, if you use one of these to power it check the following:

There are many different NodeMCU boards with slight variations between them. There are some NodeMCU boards that have a pin marked VU.

This pin, VU, is a direct positive connection to the USB. In practice, it is like bypassing the diode.

You can use it to connect the sensor to this pin if it suits you.

Link:

Datasheet