Carbon Dioxide CO2 Sensor (Arduino & Raspberry Pi Compatible)

This Carbon Dioxide Sensor detects the level of Carbon Dioxide (CO2) in the air. Useful for greenhouses and medical projects.  Sends an analog signal that decreases as the concentration of CO2 increases. This module also includes a digital output pin with TTL output. The Potentiometer on board is used to set the Digital Output Setpoint.  After setting the potentiometer threshold, once that threshold is reached, an LED on the sensor will illuminate and the digital pin will give a HIGH voltage signal.

Specifications:

• Wide detecting scope
• High sensitivity & stability
• Simple drive circuit
• Detection Zone: 0 - 10000ppm
• Characteristic Gas: CO2 (Carbon Dioxide)
• Operating Voltage: 6V DC.
• Digital output: Active low (When it outputs a low level signal, the indicator LED will be on)
• Analog output: Two Range Options: 0 to 2V or 0V to 4V. The default is 0V to 2V DC
• Compatible with Arduino & Raspberry Pi (for use on analog output with Raspberry Pi you will need an Analog to Digital Converter Chip)
• Pinout:
• VCC: 6V ( You can use a 4 AA battery holder for this )
• AOUT: Analog Output (voltage decreases as CO2 Levels increase)
• DOUT: Digital Output that goes HIGH when the threshold is reached (set the threshold by turning the onboard potentiometer)
• GND: 0V

Useful code for Raspberry Pi: https://github.com/intel-iot-devkit/upm/blob/master/examples/python/mg811.py 

Note: Please pre-heat the sensor before first use, typically a couple of hours minimum, so measurements are stable (hours to days is the recommendation). To preheat the board must be powered from an external power supply (not USB) at 5V, since the heater will consume significant current. Calibration at 400ppm and 1000ppm is recommended to return accurate results.