pico

A-Star Micro tiny 4 switch keypad

• Pololu A-Star Micro
• Atmega32U4
• 6x6mm square tactile switches
• 1.2mm pcb for top and bottom
• Simple Arduino sketch  

Tiny backpack for the Pololu A-Star Micro board. There is also a board on the bottom to protect the bottom of the A-Star since it has components on both sides of the PCB.

The PCB is 3 parts connected together. They need to be snapped apart and then filed flat. One of the boards is for the 2 key Pro Micro. It cost the same for the composite layout as it would for a single small PCB, so combining them reduced the cost.

It's tiny.

Side view. You can see the top PCB for the switches, then a socket, the A-Star Micro, and then the bottom PCB.
The pins from the switches need to be trimmed flush with the bottom of the PCB after soldering.
Also some electrical tape underneath to insulate the USB connector form the bottom of the switches.

Size Comparison. Micro TMK, 2 Key Pro Micro, Nano TMK, Pico

All my ortholinear boards. i75, Planck, Flanck, Flanck 2.0, Gherkin, Flanck 3.0, 2 Key Pro Micro, Nano TMK, Pico

PCB / PCB broken apart / PCB after filing down the nubs.

Blurry picture of A-Star Micro with PCBs.