Here is a gas leak detector circuit that detects the leakage of LPG
gas and alerts the user through audio-visual indications. The circuit
operates off a 9V PP3 battery. Zener diode ZD1 is used to convert 9V
into 5V DC to drive the gas sensor module.
The gas leakage circuit uses the SEN-1327 gas sensor module
from RhydoLABZ. Its output goes high when the gas level reaches or
exceeds certain point. A preset in the module is used to set the
threshold. Interfacing with the sensor module is done through a 4-pin
SIP header.
Pin details of the gas sensor module are shown in Fig. 2. An MQ-6 gas sensor is used in the gas sensor module. The sensor can also be used to detect combustible gases, especially methane.
Whenever there is LPG concentration of 1000 ppm (parts per million)
in the area, the OUT pin of the sensor module goes high. This signal
drives timer IC 555, which is wired as an astable multivibrator. The
multivibrator basically works as a tone generator.
Output pin 3 of IC 555 is connected to LED1 and speaker-driver transistor SL100 through current-limiting resistors R5 and R4, respectively. LED1 glows and the alarm sounds to alert the user of gas leakage. The pitch of the tone can be changed by varying preset VR1. Use a suitable heat-sink for transistor SL100.
 |
Gas leak detector schematic |
The gas leakage circuit uses the SEN-1327 gas sensor module
from RhydoLABZ. Its output goes high when the gas level reaches or
exceeds certain point. A preset in the module is used to set the
threshold. Interfacing with the sensor module is done through a 4-pin
SIP header.Pin details of the gas sensor module are shown in Fig. 2. An MQ-6 gas sensor is used in the gas sensor module. The sensor can also be used to detect combustible gases, especially methane.
Whenever there is LPG concentration of 1000 ppm (parts per million)
in the area, the OUT pin of the sensor module goes high. This signal
drives timer IC 555, which is wired as an astable multivibrator. The
multivibrator basically works as a tone generator.Output pin 3 of IC 555 is connected to LED1 and speaker-driver transistor SL100 through current-limiting resistors R5 and R4, respectively. LED1 glows and the alarm sounds to alert the user of gas leakage. The pitch of the tone can be changed by varying preset VR1. Use a suitable heat-sink for transistor SL100.
