Future scope for gsm based gas detecting system
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The circuit for a LPG leak detector is readily available on the market, but is extremely expensive and generally based on a microcontroller (MCU). Here is presented an inexpensive circuit for an LPG detector that can be easily constructed.
LPG Leak Detector Circuit and Operation
The circuit diagram of the low-cost LPG detector is shown in Fig. 2. Around the lowering transformer X1, two rectifier diodes 1N4007 (D1 and D2), a capacitor of 1000μF (C1), 7805 voltage regulator (T2), high-gain 12V siren / buzzer (PZ1), and some other components. In addition, the MQ-6 LPG gas sensor (GS1), dual LM393 IC2 comparator IC2), darlington TIP122 (T2) transistor,
Parts List Transformer X1 rectifies the mains supply through a full-wave rectifier comprising the diodes D1 and D2, filtered by the capacitor C1 and fed to the regulator 7805 (IC1) to maintain a constant 5V DC output which is fed to the circuit .
At the heart of the circuit is dual comparator IC LM393 (IC2). It is used to compare two different voltages, namely reference voltage and output voltage of the MQ-6 gas sensor.
The reference voltage on the non-inverting pin 3 of IC2 is set using the VR1 potentiometer to adjust the voltage levels according to the sensitivity requirements. The output voltage of the LPG sensor (MQ-6) is fed to the inverter pin 2 of IC2.
If the reference voltage (pin 3 of IC2) is less than the voltage of the sensor (pin 2 of IC2), the output goes down, which means that there is no leakage of LPG. With a low output, T1 remains cut off and there is no current flow through the buzzer; It does not ring and remains in silent mode.
If the reference voltage is greater than the voltage of the sensor, the output is high, which means that there are LPG leaks. The high output switches on the T1 transistor and the buzzer sound loudly to alert the people around.
It is very easy to find gas leaks with this circuit, which uses low cost components and an interactive way to adjust different levels of sensitivity, based on customer needs, with the help of the VR1 potmeter.