This board is designed to be used with the OctaBeat music visualiser, and adds connectors for external 12VDC power and line-level audio input, as well as an electret microphone which can be used as an alternative to the audio input. It connects to any male Output header on an OctaBeat board and supplies power and audio to all connected boards in the arrangement.

A centre-positive 2.5mm DC socket is used for the 12VDC input, and two 3.5mm stereo audio sockets provide for loop-though audio input (alternatively a Y-splitter cable can be used to supply the signal to the OctaBeat as well as to another device).

The board can also be constructed as a general-purpose microphone pre-amplifier for operation on a 5-12VDC supply by wiring pin 7 at the header H1, to pin 1 of jumper J1 (with jumper pins 2 and 3 also shorted), and omitting R5. The 3.5mm audio sockets are now be used for output of the line-level amplified audio signal from the microphone.

Instructions for usage and assembly are included in the OctaBeat manual. Note that use of the microphone input with the OctaBeat boards may be unreliable due to supply ripple when the LEDs turn on, in which case a separate 5-12VDC power supply may be required just for this board. See the manual for details.

Full details including manual and schematics