ROLLS MIDI PEDALBOARD CONTROLLER
I've been asked to modernised an old (90's ?) midi pedalboard which sent only program change, the user
wanted to send midi_note_on and midi_note_off data.
the board was really old fashion, very 90's maybe. No microcontroller, all digital logic.
However, today is all about microcontroller so I decided to use one of those. A cheap STM32f0 was perfect
for that very low end application. As today is also about SMD, the board was designed with 0805 SMD
packages.
When PCBs are order form China they come by 5 or 10 pieces. The cost is lower that way. To avoid waste,
I designed the PCB to be able to use it for any other MIDI related applications. Therefore all the unused pins
are available. This went handy for another project, a small midi controller.
another important factor was the price, I wanted the pcb to cost the less possible. Hence the choise of 0805 package.
Designing the board was a bit tedious as I needed to take exact mesurement to place correctely the 7segment display and
the back connector. Well, I managed to do it nicely but I've lost few neurones in the process.
The flow of code is very simple, a ring buffer is used to collect and send midi data out. The 7segment display
is used to display what the last action was.
From the outside nothing has changed, but the inner working is all diferent now.
SCHEMATIC