Mochi40 Hotswap PCB & Build

Work performed

PCB sourcing and hotswap build based on the open-source Mochi40 design.

The build supports an Elite-C microcontroller for wired configurations or a nice!nano for wireless configurations. The PCB supports up to 60 hotswap switches, an optional SSD1306 OLED display, and an optional EC11 rotary encoder.

Required hardware includes 1N4148 through-hole diodes, hotswap sockets, M2 heat-set inserts and screws, and the appropriate microcontroller. The case can be assembled using M2 heat inserts and screws, with optional OLED, rotary knob, and acrylic cover depending on the selected configuration.

Project specifications

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Mochi40

Layout

• 40% compact layout
• Tray-mount case
• Up to 60 switches
• Hotswap PCB

PCB

• Mochi40 Hotswap PCB

• PCB sourced/manufactured through LionCircuits

• Approximate PCB cost:

  • ₹631 per PCB at MOQ 5
  • ₹566 per PCB at MOQ 10

Microcontroller

• Elite-C — wired configuration
• nice!nano — wireless configuration
• Standard Pro Micro boards without the required bottom-row pins are not compatible

OLED

• Optional SSD1306 OLED
• 128×64 supported
• 128×32 supported
• Available from Robu

Rotary Encoder

• Optional EC11 rotary encoder
• Knob can be 3D printed
• Available from Robu

Switches / Hotswap

• 60 × hotswap sockets
• Supports up to 60 switches

Diodes

• 60 × 1N4148 through-hole diodes

Reset

• 1 × reset switch
• Optional depending on configuration

Case Hardware

• 9 × M2 heat-set inserts
• 9 × 5 mm M2 screws
• Hardware requirements may vary depending on the case mounting method

Optional Accessories

• OLED display
• Rotary encoder
• 3D-printed knob
• Acrylic cover
• Keycaps
• Wireless controller

BOM / Reference

Open-source project:
https://github.com/Aidan-OS/Mochi40

Full BOM:
https://github.com/Aidan-OS/Mochi40/blob/main/BOM.csv