Function:

With the continuous improvement of people's living standards, gas and natural gas have entered thousands of households, bringing convenience to everyone, but also there are many safety hazards. Gas poisoning accidents also occur from time to time.

For this reason, we must have gas The leaked place is regularly inspected. The gas detection and alarm circuit is composed of components such as gas sensor MQ5, voltage comparator LM393 and voice chip C002. It can detect the combustible gas in the air and automatically sound and light alarm.

Circuit principle:

The gas sensing material used in the MQ-2 gas sensor is tin dioxide (Sn02) with low conductivity in clean air. When there is flammable gas in the environment where the sensor is located, the conductivity of the sensor varies with the concentration of flammable gas in the air. Increased and increased, it is suitable for household or industrial detection devices for gas, natural gas and liquefied gas, and has excellent resistance to ethanol and smoke interference.

It is an economical sensor suitable for a variety of applications. C002 is a three-tone optional alarm sound voice chip, which internally stores the sound of police car 110, fire alarm 119 and ambulance 120. The external oscillating resistor is lOOK ~ 240Kohm (the higher the resistance, the slower the sound speed), it can be driven after power-on.

The buzzer sounds. 1 pin grounding, 2 pin output, 3 pin selection sound terminal, 4 feet connected to the positive pole of the power supply, 5 and 6 feet connected to the oscillation resistor. The gas detection and alarm circuit uses the alarm sound of the fire alarm 119, and its working voltage is generally 2.4 to 3.6V.