DTMF Shield

DTMF  Technology is one of the prominent technology that gives us the freedom to remotely control devices through mobile phones.  By using this shield you can control your devices from a  long distance.  And this shield interfaced easily with a microcontroller. This DTMF Shield is based on a Dual-tone multi-frequency signalling module decoder for Arduino. The audio connector in the board decodes the crazy funny noises common phones make. This Shield functions as an Audio code system allowing you to send commands to your Arduino via Audio signal.

DTMF  (DUAL TONE  MULTIPLE  FREQUENCY) shields are based on MT8870D IC which is a DTMF receiver.  It has two sections one is a band split filter and the other is the digital decoder.  Band split filter separates the low and high group tones while the digital decoder decodes all 16 DTMF tones pairs into 4-bit code. When a key is pressed, DTMF IC simply generates two frequencies corresponding to the number pressed on the keypad.  This  DTMF  Shield works perfectly with microcontroller boards like  8051,  Arduino,  PIC, etc.

This module can communicate to Arduino with any phone landline or Cell phone in the world, together with GMS / GPRS / GPS shield within the GSM signal range. An audio jack of 3.5mm is used to connect DTMF Shield with the phone.  Moreover, this features  Low power consumption,  Adjustable guard time, internal gain setting amplifier, Power-down mode, Small size, and high performance.  4 bits of  DATA  send as  OUTPUT by the shield and take input from a mobile phone connected through a 3.5mm audio jack.  As a result, the   DTMF receives DATA  from a Mobile phone and converts it into a TTL  Level signal.  So that microcontroller can process these signals.