Note: the new front panel board will use shift register chips to obtain all the LED output data, so that only 8 signal lines will be needed between the boards. The new boards will use a dual-row 16-pin header (more pins for power this time), so it'll be easier to interconnect the boards with nice ribbon cable and standard IDC connectors. The shift registers should also make it easy to add more LEDs to the design.

Front Panel Schematic:

schematic diagram

TODO: add some explaination, though this circuitry is pretty simple.

TODO: make a page with the front panel board artwork, and draw a nice parts placement diagram.

or skip to the firmware.

The MIDI Drum Machine, Paul Stoffregen and Rod Seely.
Designed and constructed Fall, 1991. Project status: Complete.
http://www.pjrc.com/tech/midi-drums/sch-front.html
Last updated: February 24, 2005
-- These drum-machine web pages are still under construction --
Questions, Comments?? <paul@pjrc.com>