MQ8 Module

This is based on the MQ-8 H2 sensor IC with Hydrogen as a gas sensing element. MQ-8 sensor is ideal for the detection or measuring hydrogen concentration at a range from 100 to 10, 000 ppm in air. It offers excellent sensitivity and fast response to H2 and also shows also has anti-interference to other gases. This makes it ideal for portable gas detectors or in other industrial applications. The module comes with basic components integrated allowing the sensor to function properly. And interfaced easily to any controller as the user prefers. Hence no external components are required, we need to just plug in Vcc & ground pins and you are ready to go.

MQ8 module consists of both digital and analogue outputs. This module not only provides a binary indication of the presence of combustible gases but also an analogue representation of their concentration in air. When gas is detected using the digital output, the indicator LED D0 turns ON. As a result, the digital pin will go from logic high to logic low 0V. The presence of onboard LM393 comparator IC compares the adjustable preset value and also eliminates the need for an external microcontroller. Simply power up the module and set the sensitivity of the digital pin using the potentiometer. So when the module detects the gas the digital pin will go low.

While using the analogue pin to measure PPM, the TTL drove (0-5V) analogue pins read values using a microcontroller that calculates the resistance value. By using the external load resistance the resistance variation is converted into a suitable voltage variation. Thus the H2 content was detected by measuring this resistance. This will be directly proportional to the concentration of the gas to which the sensor detects.