Dtmf decoder for mobile phones

Thread Starter


Joined Feb 15, 2014
Hai sir,
I am doing a project on cellphone based remote controller for water pump.i have just connected the dtmf decoder part using ic mt8870 and connected leds to pin 11,12,13,14 . When I supplied a 5 v as vcc ,1 leds lights up without cellphone in the circuit.i have not connected the cell phone to the circuit but one of the leds light up what can be the reason. Also can we connect all cellphones,to the circuit. How can I connect my cellphone with the circuit. Pls rply soon.if possible today itself.