Winsen MH-Z19B CO2 Sensor with Cable

This is not possible in most cases. Most development boards (including Uno, Mega, NodeMCU, D1 Mini V3, etc.) have a diode between the 5V pin and the USB input that lowers the voltage. If the voltage from the 5V pin is lower than the required minimum of the device (see specifications) then it cannot function properly. In addition, many development boards can only provide little power. This can also cause it to malfunction. Using an insufficient power supply can even damage the device. Therefore, make sure that you use a suitable power supply and that it is connected correctly. It is advised to verify the supply voltage by measuring it.

In most cases, this is caused by insufficient power supply condition. When the power supply provides too little current, has too low a voltage and/or generates too much ripple, several problems can arise, such as:

• Unstable measurements;
• Communication error between development board and sensor;
• A sensor that doesn't work at all;
• Damage to the sensor.

A good quality power supply is required that can supply enough current and has the correct voltage (see sensor specifications in the product description). It is advised to measure the voltage directly on the Vcc and GND pins of the sensor.