ArdCore Output Expander
The output expander is available as both a complete module and DIY circuit board. The output expander works by providing individual bit output of the 8-bit analog output, providing a wealth of gates, triggers and switching lines for creative patching.
An example of this in use can be seen in this video:
Building Out the Output Expander Board
The BOM for the output expander board is as follows:
Much of the building information is similar to that found for the main ArdCore board. If you choose to connect directly to the components (the LEDs, jacks, power supply and ArdCore board), you can get away without the MTA connectors.
The basic scheme of the output expander is that it accepts the raw bit input from the ArdCore board, then buffers those values to the LEDs and output jacks. We use the power system from the standard Synthesizers.com connection, but only use the Ground and +5V lines for this board.
The SN74ALS541N buffer chip isolates the jacks and LEDs from the CPU, thereby preventing any overdraw on the Arduino's pin outputs, and preventing them from accidentally receiving unwanted voltage from the outside world.