All of us aware of the danger while handling the LPG gas cylinders which uses in the kitchen or in the motor vehicles. LPG gas is supplied in pressurized steel cylinders. When the gas leakes from a cylinder, it it flows along floor and tends to settle down in low spots of the room, because the LPG is heavier than air. If not properly exhausted, this can cause, fire or suffocation.
|Fig. 1: Circuit for gas leakage alarm|
|Fig. 2: Pin details of gas|
Here is an electronic circuit that detects LPG presence and alert the user through LED and speaker alarm. The circuit is based on the 555 timer IC which is available easily. A 9V battery can be used to operate this equipment and the zenar diode used cover the supply to 5V dc. This drives the LPG gas sensor module SEN-1327 from RhydoLABZ. This is an active high device, which means the output goes high when the gas level exceeds a minimum level in the vicinity.
The Gas detector is sensitive to propane, butane, isobutene, LPG and natural gas as per the data sheet. It can also be used to detect combustible gas mainly methane.
Threshold LPG concentration : 1000 ppm
The multivibrator basically works as a tone generator which is triggered by the high output of the gas sensor module. The pitch of the tone can be changed by varying preset VR1. Use a suitable heat-sink for transistor SL100.