I have another new project, the project is simple one when a call lands to the mobile an ac machine is triggered and it turns off when the mobile ring stop, for that I have used this circuit
The issue is that I have looped out the connection from vibrator of an old cell phone to this circuit , I need to turn this ac machine continually till the call rings , I have no other option other than the vibrator output , let me know how to modify the circuit thereby the circuit remains on till the call ends
here the vibrator outputs 0—2.1 —0—-2.1—-0——2.1 volts and
the interval is around 1sec; so I need to implement another
modification that the optocoupler will remain in ON state for 1sec,
then the circuit will probably remain on for a time of 180 sec from the start of the call.> My requirement is when the 2.1v comes across the vibrator output the
circuit must be turned on and it must persist in the On state for 180
or (180 x 2 )seconds after that turns off automatically
Best Answer
You may be able to get the circuit to stay on all the while the call is ringing by adding a capacitor as shown below. In this application the capacitor may have to be multiple uF in size. Select the capacitor to suit the cadence of the phone vibrator signal.
If the capacitor gets too large then it may take more than one ring cycle before the capacitor charges sufficiently through the 470 ohm resistor to turn on the 2N2222.