Circuit Lake

Electronic Project and Circuit Collection

PIC Based DTMF controller

04/16/2011 Category: Control, Digital, Microcontroller, PIC, Project

This DTMF controller is built based on PIC16F84A Microcontroller, MT8870 DTMF receiver, and an ULN2803A relay driver. The Controller has 8 OC outputs to drive 8 5/12V relays of any type. In addition to 8 OC outputs, header/terminal socket also provides 12V, Ground & 5V (for pull-ups only).


The project firmware is written in Assembly language with default password 1234. If you want to change the password, you need to edit the .ASM file and re-compile the file before programming the PIC. Download : schematic and source code