Comparison and Experimentation with Flammable Gas Sensors Created by Kevin Walters
Last updated on 2021-01-15 03:29:26 PM EST Guide Contents
Guide Contents 2 Overview 3 Parts 3 Gas Sensor Types 5 Metal Oxide Semiconductor 5 Catalytic 5 Electrochemical (battery) 5 Non-dispersive Infrared 6 Avian 6 More information 6 Connect the Sensor Boards 8 Soldering 8 Power Supply 8 Connecting everything 9 Enable line 10 CircuitPython 11 Sensor Burn-in 13 Testing Gases 17 Board Comparison 19 Does airflow have an influence on the measurement? 19 Does the gas need to be flowing across the Metal Oxide Semiconductor sensor? 19 Going Further 20 Ideas for Areas to Explore 20 Related Projects 20 Further Reading 20
© Adafruit Industries https://learn.adafruit.com/gas-sensor-comparison Page 2 of 23 Overview
Hanwei (https://adafru.it/CPX)/Winsen (https://adafru.it/CPY) and SGX Sensortech (https://adafru.it/CPZ) produce a range of sensors for gas detection and measurement. This project demonstrates how to use the MQ-3 and MiCS-5524 sensors. These are based on a heated, metal oxide semiconductor which varies in resistance in the presence of a gas or vapour that can be oxidised - this includes some hydrocarbons, alcohols, ammonia and carbon monoxide. This change of sensor resistance can easily be determined from an on-board potential divider circuit producing a voltage. That voltage can be measured on an analogue (ADC (https://adafru.it/eYp)) input.