DTMF Shield for Arduino

DTMF Shield for Arduino


Plugs into an Arduino board and convert DTMF (Touch Tone) signals into digital so that Arduino and other microcontrollers can understand.

At the heart of this module is a DTMF decoder chip. This application specific chip that does all the heavy lifting so that the interface with your Sketch is easy.

Available on backorder

SKU: dtmf. Category: .

Product Description

Here’s a functional diagram of the DTMF Shield:

DTMF Shield Functional Diagram

Key Features:

  • Operating Voltage: 5v, Current draw: 3mA
  • Input signal range: 27.5 to 869mVrms  (-29 to 1dBm )
  • Trim pot for easy gain adjustment.
  • 3.5mm stereo audio jack (TRS) and 0.1″ standard interface headers
  • Easy to reconfigure the audio jack pinout
  • LED to indicate tone decoded


  •  0.79″ x 2.16″, 20mm x 55mm


Demo Video:

Below is a collection of videos demonstrating the operation of the DTMF Shield. You’ll notice that some of the videos the prototype DTMF boards. The earlier boards did not have the Arduino headers. The final board I refer to as the v400. That is the board I provide the documentation above.

Video of initial prototype. Please notice board layout changed

Other demo videos here

Board Loopback Test

Below is the library for the DTMF shield along with instructions on how to install them. As a sample sketch I created the loopback test where the shield sends a DTMF tone and decode that same tone it sent out!

Preparation Steps: 

  1. Download & install the Arduino IDE  ( http://arduino.googlecode.com/files/arduino-1.0.5-windows.exe )
  2. Download & unzip Test Code: https://github.com/isramos/dtmf-shield/archive/master.zip
  3. Move folder “Tone” to:  Documents/Arduino/Libraries
  4. Arduino IDE click File –> open : dtmf_plug_in_loopback.ino

Run the test

run the “Loopback test”described in the DTMF Shield manual  http://www.dossant.com/public_files/dtmf_module/dtmf_v400/DTMF_Module_v400_user_manual.pdf


  1. hutterite


    Awesome product — shaved a few days off my prototyping time!!!

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