BMC45. Random Rhythm
This module is a PIC based 4x4 patching matrix. The four inputs on the bottom are routed to the four outputs on the right, and the routing pattern is controlled by the pushbuttons. Patterns are saved to one of sixteen memory bank slots which are selected with the knob on the lower left, these are saved and loaded using the pushbuttons. The module is powerful and easy to use.
The board features PC mounted pots, LEDs and pushbuttons for less wiring, but jacks are mounted off board so the design is friendly for 3.5mm, 1/4" or banana jacks. There are Eurorack and MOTM power connecters. It can be built in +/-12V or +/-15V systems without any modifications.
For complete information on this module, download this PDF file.
The required set of two PCBs and a programmed 16F914 PIC is $26.
Unfinished panels are for sale for $9 each. Please read this page on unfinished panels before ordering.
If you'd like to drill your own panel, here is the drill guide that I use to make these panels. It should be printed at 300dpi.