NeoBoomerang - A One Handed Chording Keyboard

Features

• I2C connections STEMMA QT connnected
  • Only one NeoKey jumper pad requires soldering
• Encoder for scrolling
• 10 NeoPixel LEDs
• USB-C
• Red Cherry MX (silent, low force)
• CircuitPython 9.x based
• Emulates a 60% keyboard with only 8 keys

FreeCAD

• FreeCAD 0.21.2
• Minimal 3D printed plate for mounting

BOM

Item	Source	Part Number
Controller	Adafruit	KB2040
Keys	Adafruit	NeoKey 1x4 QT I2C
Encoder	Adafruit	I2C Stemma QT Rotary Encoder
Cables	Adafruit	STEMMA QT 50mm
Cables	Adafruit	STEMMA QT 200mm
Screws	Adafruit	M2.5 Machine Screws / Stand-off

Typing Speed

• 20 WPM is my best
• 16-18 WPM is typical

Left Handed Layout

• UV buttons are for fingers:

  1. Index finger
  2. Middle finger
  3. Ring finger
  4. Pinky finger

• Thumb

  • Blue: white space
  • Green: letters
  • Yellow: numbers
  • Red: delete