reversible

dumbpad

Designed by imchipwood in Portland, Oregon, USA

Special thanks to QMK for open-source keyboard firmware

Description

dumbpad is a simple 4x4 numpad with a rotary encoder. It is designed for the ATmega32u4-based Pro Micro but any ATmega32u4-based microcontroller using the same form factor should work

It is designed to run QMK firmware - check qmk_firmware/keyboards/dumbpad for compiling & uploading instructions

Revisions

• v0.5 introduces 2x LEDs for indicating which layer is enabled, accurately representing up to 4 layers
• v0.6_dualencoder is a true 4x4 macropad with two rotary encoders - one in each bottom corner
• v0.6_dualencoder_top is the same as v0.6_dualencoder but the encoders are moved to the top corners
• v0.7 PCB is flippable. Two jumpers must be soldered:
  • Encoder on left (default layout) - solder the left side of the jumpers to the center
  • Encoder on right (PCB upside down) - solder the right side of the jumpers to the center
• v1.0 PCB adds a 3rd LED - default use is to indicate if NUMLOCK is on

dumbpad v0.2 (top) & v0.7 (bottom), PCB by OSH Park

Dual-encoder version by chicocode:

Eagle PCB render

Bill of materials

• 16x Cherry-style mechanical switches
• 17x 1n4148 diodes (thru hole)
• 1x Arduino Pro Micro or pin-compatible ATmega32u4-based MCU
• 1x EC11 rotary encoder with pushbutton (7-pin)
• (optional) 1x 6mm tactile switch (to reset MCU)
• (optional) 3x 3mm LEDs (whatever color)
• (optional) 3x 330ohm or similar resistors for the LEDS (not needed if not adding LEDs)

Notes

• No case is currently available, but v1.0 has 2mm mounting holes in a 40mm square centered at x=58.575mm, y=39.425mm (from the bottom left)
  • 38.575, 19.425
  • 38.575, 59.425
  • 78.575, 19.425
  • 78.575, 59.425
• To avoid damaging the PCB and prevent it from sliding around, put rubber feet on the bottom of the PCB
  • place feet directly under the rotary encoder(s) as they take significant force to press
  • place the others in the corners and one in the center

Making the PCB

Submit the .brd file to your preferred PCB manufacturer - be mindful of minimum quantity requirements.

OSH Park - USA PCB Manufacturing

Shameless Portland, Oregon company plug - OSH Park is a fast and reliable manufacturer, combining multiple individual orders into a single panel to minimize end-user costs. dumbpad is just under $60 for 3 copies through OSH Park.