midi-fader

Public

@kcuzner

Loading 3D model… large boards can take a moment.

README

Simple MIDI Fader

By Kevin Cuzner

Project Status

PCB complete and working (with an additional load added to reduce regulator noise)
Firmware feature-complete and mostly working
- Emulates as HID and USB-MIDI devices
- Not tested on Windows yet
Case OpenSCAD in progress
Configuration host software in progress

Featureset

Two 60mm analog fader inputs
USB Audio Class interface, aiming for driverless on Windows 7 and 10
Driverless HID interface for configuration
- It might be trivially simple to echo the fader status in the HID reports...

Main Component Options

Faders (note that they have different footprints and different levers):
- Expensive faders ($4.74, very light movement force): PTB6053-2010APB103-ND
- Cheap faders ($1.73): PTA6043-2015CPB103-ND
Microcontrollers:
- 497-17354-1-ND: STM32F070F6P6, $1.48, 32K flash, 6K RAM, 20-TSSOP.
  - No CRS, external XTAL required.
- 497-15099-ND: STM32F070CBT6, $2.52, 128K flash, 16K RAM, 48-LQFP
  - No CRS, exteranl XTAL required.
- 497-17344-ND: STM32042F6P6, $2.25, 32K flash, 6K RAM, 20-TSSOP.
  - Has a CRS
  - 24.6mA with all peripherals and HSI48 enabled
609-4052-1-ND: Micro-USB, $0.76
455-1790-1-ND: JST-SH header for programming, $0.63
Power supply solution:
- MCP1603T-330I/OSCT-ND: Cheap buck regulator, but not too cheap. $1.01, TSOT-23
  - Noise issues at low currents (leaves PWM mode and skips pulses).
- 576-4764-1-ND: MIC5504 buck regulator, $0.11, SOT23-5.
  - At a 100mA load, the case will heat 42.6C. Not over the top, but really quite hot.
  - We could do this AND the buck regulator, but just have this for the analog.

Notes

Notes about the logical MIDI protocol

MIDI has two types of bytes STATUS and DATA.
A STATUS byte has its MSB set
A DATA byte has its MSB cleared (hence why there are only ever 0 to 127 data values)
Usually, the lower nybble of the STATUS byte is a channel number (there are 16 channels).

Comments

Simple MIDI Fader

By Kevin Cuzner

Project Status

PCB complete and working (with an additional load added to reduce regulator noise)

Firmware feature-complete and mostly working

Emulates as HID and USB-MIDI devices
Not tested on Windows yet

Case OpenSCAD in progress

Configuration host software in progress

Featureset

Two 60mm analog fader inputs

USB Audio Class interface, aiming for driverless on Windows 7 and 10

Driverless HID interface for configuration

It might be trivially simple to echo the fader status in the HID reports...

Main Component Options

Faders (note that they have different footprints and different levers):

Expensive faders ($4.74, very light movement force): PTB6053-2010APB103-ND
Cheap faders ($1.73): PTA6043-2015CPB103-ND

Microcontrollers:

497-17354-1-ND: STM32F070F6P6, $1.48, 32K flash, 6K RAM, 20-TSSOP.
- No CRS, external XTAL required.
497-15099-ND: STM32F070CBT6, $2.52, 128K flash, 16K RAM, 48-LQFP
- No CRS, exteranl XTAL required.
497-17344-ND: STM32042F6P6, $2.25, 32K flash, 6K RAM, 20-TSSOP.
- Has a CRS
- 24.6mA with all peripherals and HSI48 enabled

609-4052-1-ND: Micro-USB, $0.76

455-1790-1-ND: JST-SH header for programming, $0.63

Power supply solution:

MCP1603T-330I/OSCT-ND: Cheap buck regulator, but not too cheap. $1.01, TSOT-23
- Noise issues at low currents (leaves PWM mode and skips pulses).
576-4764-1-ND: MIC5504 buck regulator, $0.11, SOT23-5.
- At a 100mA load, the case will heat 42.6C. Not over the top, but really quite hot.
- We could do this AND the buck regulator, but just have this for the analog.

Notes

Notes about the logical MIDI protocol

MIDI has two types of bytes STATUS and DATA.

A STATUS byte has its MSB set

A DATA byte has its MSB cleared (hence why there are only ever 0 to 127 data values)

Usually, the lower nybble of the STATUS byte is a channel number (there are 16 channels).

midi-fader

Share midi-fader

Simple MIDI Fader

Project Status

Featureset

Main Component Options

Notes

Notes about the logical MIDI protocol

Sign in to BoardRepo

Simple MIDI Fader

Project Status

Featureset

Main Component Options

Notes

Notes about the logical MIDI protocol

Notes about USB and MIDI