Take a look at the:

• teensy-thumb-keyboard github for KiCad PCB files, Fusion360 model links, 3d printer STLs and example Arduino keyboard firmware sketch.
• hackaday.io page for more photos, info and project Logs
• thingiverse HyperPixel 4 & Raspberry Pi 3 B+ Handheld for the 3d printed faceplate shown in the photos.

What is it?

This is a breakout PCB in the shape of a thumb keyboard for the Teensy 3.2, Teensy LC, or Butterfly STM32L433. Please Note this listing is for a bare PCB only. Parts, Teensy and some soldering required for a fully working keyboard.

Why did you make it?

I wanted a small tactile keyboard with a comfortable layout that could be used in any handheld hardware project. BASIC game console, graphing calculator, PDA, Raspberry Pi handheld computer, etc.

Features

• 60 keys arranged in a 6x10 matrix (uses 16 pins on the microcontroller).
• Silkscreen has a qwerty layout with number keys arranged in a numpad.
• Lead free ENIG-RoHs surface finish with 2oz copper.
• SPI, I2C, and 2 additional GPIOs broken out.
• Each pin along the edge of the Teensy is connected to one extra pin in the prototyping area.
• Beginner friendly through hole soldering.
• Example Arduino sketch firmware provided. Additional details in the Example Firmware Posted project log.
• Layout is completely customizable in the firmware.
• qmk_firmware should also work (support guide) However, I don't have an example running yet.

Three possible mounting options

1. Teensy on the front, mounted right-side up, with usb port facing north.
2. Teensy on the back, mounted upside down, with usb port facing north or south.
3. Teensy on the back, mounted upside down, with usb port facing south. Note: Breakout pins will only work as expected with USB facing north.

Parts list for a fully working keyboard

• 1x Teensy 3.2 or Teensy LC. A Butterfly STM32L433 will also work (though not as a USB keyboard).
• 10x 1N4148 Diodes
• 60x Panasonic EVQ-PAC04M Tacticle Switches. These are the quieter and higher quality switches. Some are available at digikey. If you wish to use the 3d printed faceplate the overall switch height must be 4.3mm. These models will also work: EVQ-PAD04M EVQ-PAE04M EVQ-PAG04M. Otherwise any standard 6x6mm momentary switch will work.

I'm putting this up here to help offset the costs of prototyping. This project is open source though so you can order a batch of these PCBs if you're comfortable doing so. Here's a couple options:

• https://oshpark.com instructions: upload the kicad_pcb file.
• https://jlcpcb.com/quote instructions: upload the gerber.zip file The settings I'd recommend for jlcpcb are: Layers: 2, Thickness: 1.6, Surface finish: LeadFree HASL-RoHs or ENIG-RoHs (don't want lead on a board you may be typing on), Copper weight: 2oz (1oz is probably fine though, the heavier weight copper stands up better to repeated solder and desoldering I think), Everything else default settings.