Here’s a functional diagram of the DTMF Shield:
- 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
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!
- Download & install the Arduino IDE ( http://arduino.googlecode.com/files/arduino-1.0.5-windows.exe )
- Download & unzip Test Code: https://github.com/isramos/dtmf-shield/archive/master.zip
- Move folder “Tone” to: Documents/Arduino/Libraries
- 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