Fully Complete Project

    As now after a long hard work the wireless gas leakage detector alarm had being 100% complete,and here i will explain some of the part of the project itself. This is the circuit for the Tx and this circuit using 12V from the adapter.
While to active/on the doorbell circuit it must used an extra supply which is battery.

Gas Sensor Circuit and Transmit ( Tx ) Circuit from wireless doorbell.

Transmitter need to use battery to active the wireless form Tx to Rx

Receiver ( Rx ) as a Alarm Alert 

Receiver ( Tx ) used 2 pin AC supply as a wireless alarm detector

Final 

From left - Box 1 - : Gas sensor that connected with adapter as a transmit wireless

- Box 2 - : Detection alarm as a receiver ( output ) 

Used lighter or any other thing that have LPG gas to active the sensor