The Audio Codec Shield is an Arduino shield that sports the Wolfson WM8731 codec (capable of stereo sample rates at 44.1ksps/16b and beyond!). The shield has 1/8″ stereo input and headphone output jacks, a single pole analog input aliasing filter, and 2 potentiometers for varying parameters in your code.

The Audio Codec Shield pins out all of the useful pins on the codec, including the microphone pins, the line in and line out pins, the headphone pins, and the midrail bias voltage pin. This extends the Shield’s productivity beyond the Arduino platform, to a general purpose breakout board for the codec. It also has a 5V to 3.3V level translator so it can be used with most microcontroller platforms.

The WM8731 has a lot of useful features, and routines have been written for most of them for both Arduino and Maple. The codec is DC coupled on both the input and output, so you can even use it as a high quality ADC and DAC for signals of all kinds. In the addition to high frequency audio sampling, the WM8731 is capable of sample rates all the way down to 2kHz . The variable sampling rate can come in handy if you need to free-up more processing time.

The Audio Codec Shield works directly with the Arudiuno Uno, Arduino Duemilanove, and Leaflabs Maple, but NOT with the Adiuno Mega. The Mega has a different pinout for its SPI bus, so some hacking is required.

For more information, visit the open music labs audio codec shield webpage.