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  • PIC16F84A based Gas Detector

  • Created: May 22, 2016

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Gas leakage that contains hazardous gas can cause a massive damage in properties when ignited and can danger many lives. The reference design is a gas detector that acknowledges the presence of several gases like liquefied gas, butane, propane, methane, alcohol, and hydrogen. The design features the PIC16F84A-04/P enhanced flash/EEPROM 8-bit microcontroller. The PIC16F84A-04/P features 13 I/O pins with individual direction control and provides a 25mA sink and source current for direct LED drive per pin.

The PIC16F84A-04/P-ND from Microchip is the main component in this design. The reference design uses the GH-312 gas sensor. The whole circuit is powered via 9V battery. The L7805 voltage regulator provides a 5V output for the PIC16F84A-04/P supply. When the GH-312 detects a gas, the GH-312 OUTPUT pin will set high which is connected to RB3 I/O pin of PIC16F84A-04/P. The LED1 and the buzzer is an indicator of gas detected and the NHD-0208AZ-FL-GBW LCD display the output.

The reference design can be incorporated with different outputs. The LCD can be replaced by a relay to trigger any DC application warning or a thyristor to enable AC application. The PIC16F84A-04/P has special features like EEPROM Data Retention greater than 40 years, code protection, power saving SLEEP mode and selectable oscillator options.



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