THIS PROJECT IS WORKING SO GOOD AND I HAVE TESTED IT. BUT BEFORE USING THIS AT YOUR KITCHEN OR CAR CHECK IT PROPERLY AND USE A CHARGABLE BATTERY OF 5 VOLT WHICH WORKS ON POWER FAILURE.
AND USE THIS AT YOUR RISK!!!!!
Step 1: Collect Material
2. LM 358 opamp(or other)
3. A buzzer
4. Two LED's
5. 10k preset
6. Two 330ohm resistance
7. one 20K resistance
8. power supply 5 volt, you can charger of your mobile
9. A 5 volt(or 4 volt) battery.
Step 2: Circuit Diagram
Step 3: Calibration
1. Rotate preset in any direction AT THE PLACE WHERE LPG IS NOT AVAILABLE IN ATMOSPHERE.
2. If RED Led is glowing and Buzzer is playing then rotate in opposite directly slowly until LED and buzzer is OFF.
3. If RED Led is not glowing then repeat step 2.
Step 4: Testing
Step 5: I Have a Video?