Doorbell That Being Modified To Fit With The Original Circuit

As being order before we must modified the doorbell so that it can be connected with our sensor circuit. And this is what we have done, we had remove the switch of the transmit ( Tx ) wireless doorbell.
Then we connect the connection wire of the transmitter wireless doorbell to the output of the gas detection sensor.When the sensor detect gas according to the concentration the relay will switch on and the doorbell circuit will sent a signal to the Rx and alarm will on.After a hard work the doorbell had being successfully combines with the real circuit.  

This is the result that we've combined the gas detector circuit and wireless doorbell transmitter(Tx). 

This is the receiver(Rx) from the wireless doorbell. 

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