โปรเจกต์ DTMF Decoder โดยใช้เพียงแค่ Arduino

As I was going through my semester project list with the choices to choose I saw a DTMF-controlled car that used the CM 8870 IC as a DTMF decoder and the encoded binary data was given to Arduino to perform the left right and forward back operations. The DTMF decoder function, the main part, used an external IC that I found difficult to integrate and was in search for a code or a library that could even replace the IC in the circuit with some additional code and couldn't find a satisfying solution. But one library based upon Goertzel algorithm (Goertzel.h) that could tell if a specific frequency was present in the tone or not by calculating number of pulses per unit time and their amplitude contribution in the given tone signal.

I used the basic example code as the base and have written a code that can detect the present dominant DTMF frequencies in the tone and can decode that to give us the number that was pressed on the other side during the phone call.