Description
This DTMF (Dual Tone Multi-Frequency) decoder module is used to break down the DTMF tone pairs used in the telephone dialing system. Being able to decode these tones from within your project means you can create something that can be easily controlled from anywhere in the world with a telephone connection (provided your project can be connected to an active telephone line). Simply call into the number your device is connected to, and by pressing different keys on the dial pad, you can read what keys are being pressed and have a microcontroller act on those inputs. This is the same method of control used by older home alarm systems and home automation systems, in a relatively easy to use and accessible package.
The breakout board is based around the MT8870 chip and has all the supporting components – just supply a telephone line by way of the headphone jack and power, and this board will provide the 16 DTMF outputs across 5 digital pins. Each of the outputs has a LED indicator to aid in troubleshooting as well.