MT8870_DTMF_Project by ScottC

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We will be using an MT8870 DTMF module with an Arduino UNO to control a small servo motor in this project. The DTMF module gives the Arduino super-powers and allows you to control the Servo motor in so many ways. For example, this tutorial will show you how to control the servo motor using: - a YouTube Video - a voice recorder - A web application (Online tone generator) - A smart phone app (DTMF Pad) - A touch-tone phone to cell-phone call All of these control methods will take advantage of the same exact Arduino code/sketch. But how??? The MT8870 DTMF decoder is quite a neat little module that allows you incorporate DTMF technology into your arduino projects. DTMF stands for Dual-Tone Multi-Frequency. DTMF tones are commonly associated with touch-tone phones and other telecommunication systems. When you press the number "1" on a touch-tone phone, two sine waves with frequencies: 697Hz and 1209Hz are combined to produce a unique DTMF signal which can be transmitted through the phone line. The MT8870 DTMF module can take this signal as an input, and decode it to produce a binary output. The DTMF module does not care how you produce the DTMF tone. However, if it receives this tone, it will decode it. We can take advantage of this feature to supply the module with tones from different sources. The module has a 3.5mm port for line input. Providing you can connect your DTMF source to this line input in some way, it should work. I must warn you, however that this is a line input and NOT a microphone input. If you wanted to use a microphone, you will need to boost or amplify the signal before sending it to the DTMF module. Here is a video of the project in action: <span style="display:block; text-align:center;"><iframe width="300" height="169" src="https://www.youtube.com/embed/QIWRuIFFkD8?feature=oembed" frameborder="0" allowfullscreen></iframe></span> For more details and information about this project - please visit my blog: http://arduinobasics.blogspot.com.au/2015/08/mt8870-dtmf-dual-tone-multi-frequency.html