MQ-5 combustible gas alarm

This project uses the combustible gas alarm made by Lichuang Mall MQ-5 combustible gas sensor. It has the function of signal output and independent use. This project is a gift solicitation project for Lichuang EDA open source hardware platform. The PCB of this project can be used in conjunction with the MCU to have a signal output function, or it can be used alone to have the function of detecting flammable gases and alarming for single-board operation. The gas-sensitive material used by the MQ-5 combustible gas sensor is tin dioxide (SnO2) with low conductivity in clean air . When there is combustible gas in the environment where the gas sensor is located, the conductivity of the combustible gas sensor increases as the concentration of combustible gas in the air increases. A simple circuit can be used to convert changes in conductivity into an output signal corresponding to that gas concentration. A voltage comparator is added to the circuit, which has analog and digital output interfaces. The buzzer is connected to the digital output interface, and the threshold of the sensor can be changed by adjusting the sliding rheostat.

Since the capacity of the button battery is low and the power supply time is too short, a DC005 is attached for AC/DC power supply.

Updated version 2.0. The modification is that the power supply is changed to power supply, but the button battery package is retained; the LDO chip is replaced by LM1117-5.0. The link is:  https://lceda.cn/editor#id=|ffe98998e62e4128afd4ca8f18626acf|61d5ba3117b54978a5655d5df92115a2 Third-party link  https ://bbs.21ic.com/icview-2960230-1-1.html Third-party link  https://www.cirmall.com/circuit/17022