Midibox PCBs

A collection of schematics and printed circuit board layouts for various Midibox NG modules, made with KiCAD. The designs were made with MCU style MIDI control surfaces in mind, but could also be useful for other applications.

• Midibox PCBs
  • OLED carrier board
    • Bill of materials
    • Assembly
    • Connections
      • Internal power
      • External power
      • PCB top side / OLED pin headers
      • PCB bottom side / other components
  • TODO

OLED carrier board

Holds eight 0.96″ OLED screens, spaced by 1.2″ for a compact design.

Only 4-wire SPI, 7-pin OLED types are supported. Be sure to check the dimensions and pinout matches before purchase!

Optional decoupling 100nF caps C1-C8 can be stuffed to improve noise rejection in case of flickering or other issues.

Bill of materials

• OLED screen x 8
• 10k 1/4W resistor
• 10µF/35V radial capacitor
• 2x8 box connector socket
• 2x8 box headers x 2
• 16-way cable
• 7-pin sockets x 8 (0.1″ spacing, for the OLEDs)
• 3-pin header
• 2-pin jumper
• 100nF ceramic capacitor x 8 (optional)

Assembly

1. Solder the sockets for the OLEDs on the top side
2. Solder all other components on the bottom side
3. Connect J2 to core/J15A using a ribbon cable
4. Configure the software

Connections

J1 connects to J15A of the STM32F4 core.

Internal power

J15_S should be set to 3.3V on the core, and JP1 to Core on this PCB.

External power

The LDO regulator on the core board can only supply 100mA. Therefore this PCB has an option to use external 3.3V power through J2. In this case JP1 should be set to Ext.

PCB top side / OLED pin headers

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PCB bottom side / other components

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TODO

• Software configuration
• Secure OLED mechanically
• Photos of PCB and working displays