Hi,
I am working on a switch that would release a relay after I hang up after the third ring of the phone. I have worked out the code and tested it succesfully. My problem that I have run into though is creating a circuit so that the micro controller could "see" when the phone rings (voltage changes). I have included a diagram of the circuit that I am currently working with. When all goes well the ground voltage from the phone ringing will trip the transistor and in turn the relay; alternating the voltage from positive to negatvie so that the input for the BS2 can "hear" the rings. When the code hears the proper number of rings, it will trip a seperate transitor and relay combo, that part is working well. It works properly, code and all, when I connect it to a 5 volt power supply, simulating the phone ringing. But I have discovered that for one reason or another I am getting a voltage of about 4 Volts from the Base of the Transistor, which prevents the phone from ringing properly when a call comes in (it doesn't ring at all, it instead "picks up" immediately - the caller hears static).
I have tried adding a diode and resistor to the base of the transistor but both attempts cause the circuit to stop working. And when I remove the 100 ohm. resistor the relay no longer works properly (it no longer switches), but the phone works properly then. I have looked at possibly using an SRC, but it looks like I might have the same problem of voltage interfering with the phone; would an SRC work in my case? Any other tips/alternatives/help are all much appreciated! Thanks for looking!
-Eschatt
I am working on a switch that would release a relay after I hang up after the third ring of the phone. I have worked out the code and tested it succesfully. My problem that I have run into though is creating a circuit so that the micro controller could "see" when the phone rings (voltage changes). I have included a diagram of the circuit that I am currently working with. When all goes well the ground voltage from the phone ringing will trip the transistor and in turn the relay; alternating the voltage from positive to negatvie so that the input for the BS2 can "hear" the rings. When the code hears the proper number of rings, it will trip a seperate transitor and relay combo, that part is working well. It works properly, code and all, when I connect it to a 5 volt power supply, simulating the phone ringing. But I have discovered that for one reason or another I am getting a voltage of about 4 Volts from the Base of the Transistor, which prevents the phone from ringing properly when a call comes in (it doesn't ring at all, it instead "picks up" immediately - the caller hears static).
I have tried adding a diode and resistor to the base of the transistor but both attempts cause the circuit to stop working. And when I remove the 100 ohm. resistor the relay no longer works properly (it no longer switches), but the phone works properly then. I have looked at possibly using an SRC, but it looks like I might have the same problem of voltage interfering with the phone; would an SRC work in my case? Any other tips/alternatives/help are all much appreciated! Thanks for looking!
-Eschatt