Now-a-days DTMF Technology is very popular because this technology gives us freedom to remotely control devices through mobile phone. This DTMF Shield is based on DTMF Technology, by using this shield you can control your devices from a long distance. And this shield cab easily interfaced with microcontroller. DTMF Shield can connect with phone through audio jack (3.5mm). Many other features like Low power consumption, Adjustable guard time, internal gain setting amplifier, Power down mode, Small size, and high performance.
This DTMF Shield is comfortable with microcontroller boards like 8051, Arduino, PIC etc. This shield sends 4 bit of DATA as OUTPUT and takes input from mobile phone connected through 3.5mm audio jack. DTMF (DUAL TONE MULTIPLE FREQUENCY) shield is based on MT8870D IC which is a DTMF receiver that has two sections one is band split filter and other is digital decoder. Band split filter performs the separation of low and high group tones while the digital decoder decodes all 16 DTMF tones pairs in to 4 bit code. DTMF IC simply generates two frequencies corresponding to a single number pressed on keypad. The frequencies which are generated corresponding to a given number are shown in figure 1.These high and low group of frequencies are specific because at these frequencies the losses are very less.
DTMF receive DATA from Mobile phone and it convert into TTL Level signal so that microcontroller can process these signals. As per requirement in our project we program our microcontroller and do our task. This Shield makes very easy to make any project related to DTMF technology. This shield can be use in different areas like Mobile/telephone controlled robot, Telephone answering machine, Paging system, Credit card system, Mobile radio etc.
MT8870 Decoder IC.
4 Output digital pins.
Operates on 5V
Includes MT8870 DTMF Receiver IC
Receives and Converts Standard DTMF Codes
Remotely Switch Devices from Anywhere Using the Phone
Easily Connects to Most Microcontrollers or Roboduino Board
Low Power Consumption
5 On-Board LED's For Data Received Indication
Standard Header Connections for Control System Connection