Saturday, December 31, 2016


Gherkin with bright green backlight

 Gherkin with Zealios. Built with germanium diodes.

1/4 brightness

65g Zealios. 2x3x4mm LEDs installed inside switch. You can see the glass germanium diodes between the switches.

LEDs glow through the bottoms of the clear Zealios.

Cheap PBT green backlit keycaps from eBay.

Friday, December 30, 2016

Germanium Diodes

Gherkin with germanium diodes

Old stock Russian diodes. Large clear glass body. You can find these on eBay from multiple sellers.

There is no benefit to using these over a 1n4148 silicon diode in a normal keyboard. They do look very different. The glass is brittle compared to the glass in a 1n4148 diode.

If building something battery powered, the lower forward voltage would keep the matrix functional at much lower voltage levels. Schottky diodes could also be used.

40% Edward keyboard was also built with these.

Some measurements of different diode types in a keyboard matrix

Thursday, December 29, 2016


GNAP 2.0 with G20 keycaps

  • Daruma
  • GNAP 2.0 PCB
  • Plateless PCB mount switches
  • 3mm stainless steel bottom plate from
  • Gateron yellow switches
  • PCB mount Cherry stabilizer  
 What goals have you set for the new year?
Blank daruma

Incomplete daruma

Fulfilled daruma

3mm bottom plate. Probably too thick.

Wednesday, December 28, 2016

Rainbow Pickle

Gherkin with WS2812b RGB LEDs

Would work better with white, instead of green, solder mask.

WS2812b strips stuck to bottom plate.

22 LEDs. Draws too much current at full brightness. These are 60/meter, the 30/meter LEDs would work better..

Wiring. Power and ground from header. Data pin is F6.

Close up of connection to header.

Copper Top

PCB top plate with copper exposed

  • 1.6mm PCB from
  • White solder mask
  • 14mm square cutouts for switches
  • Gateron yellow switches
  • FourtyTwo PCB
The white solder mask was sanded off to expose the copper layer. The copper has started to patina.

Copper top very easy to scratch.

Brass spacers and screws.

Compared to a top with the white solder mask.

Saturday, December 24, 2016

Dyeing PCB

Dyeing a bare FR4 PCB plates

Sanded off the green solder mask down to the bare fiberglass board. Looked like this before dying. I wet sanded to avoid fiberglass dust.

Followed the iDye Poly instructions. Only dyed for 15 minutes. Also dyed the nylon screws and spacers at the same time.

I could have sanded more in the center areas of the top plate where it is a little lighter. Having a slightly roughed up surface helps the dye penetrate.

Overall, pretty satisfied with the results.

Friday, December 23, 2016

Gherkin Assembly

Gherkin assembly notes

Test fitting all the parts together before soldering anything. You may need to trim/grind some parts to make them fit.

Board assembled with diodes and optional resistors.
Choose appropriate value resistors for the LEDs you are using.
100Kohm and 100ohm resistors for MOSFET.
Diodes are polarized, align the black stripe with the stripe on the board.

Bottom of board with SOIC-8 MOSFET and socket.
This socket was a 28 pin socket I trimmed down to 24 pins. Also the cross supports were cut off since the plastic PCB pins from the switch would press against them.

Here's a nice video on soldering SOIC parts:
There is a dot instead of a line on the Gherkin PCB.

This is a low profile socket. You can see the pins of the switch will touch the Pro Micro. They will need to be trimmed after soldering.

Full height socket. There is enough clearance to not need to trim the pins. There is also enough height for Holtite sockets. You may need to take a Dremel grinder bit to make some grooves in the socket so the Holtites don't touch the inner wall of the socket.

Pro Micro with diode leads soldered on to make it socketable

You can see what it looks like when soldering the diodes pins in this post.

Pro Micro installed. Don't install upside down, it will short out.

The unused pins from the Pro Micro are broken out to the pins below. You may want to attach some wires or a small switch to GND and RESET ( pins 8 and 9 ) to make it easier to get into the bootloader.

Thursday, December 22, 2016


A-Star Micro tiny 4 switch keypad

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.

Thursday, December 15, 2016

Gherkin Tester

Gherkin with Holtite sockets

Number Brand Type Case LED Color
1 Gateron Black Milky 3mm flanged Red/Green self flashing 1Hz
2 Gateron Yellow Milky 3mm flanged RGB slow self flashing
3 Gateron Red Milky 2x3x4mm RGB fast self flashing
4 Gateron Clear Milky 2x3x4mm RGB slow self flashing
5 Gateron Brown Milky 1.8mm Red
6 Gateron Blue Milky 1.8mm Green
7 Gateron Clear Milky Dyed Orange 3mm flanged Blue
8 Gateron Clear Milky Dyed Blue 3mm flanged Diffused Blue
9 Gateron Red Milky Dyed Blue 2x3x4mm UV
10 Gateron Black Milky Dyed Dark Green 1.8mm UV
11 Gateron Red Clear top 2x3x4mm Red
12 Gateron Clear Clear top 2x3x4mm White
13 Gateron Yellow Clear top 2x3x4mm Warm White
14 Gateron Brown Clear top 3mm flanged White
15 Gateron Brown RGB 5mm flanged White
16 Gateron Green Clear top 3mm flanged Red/Green Bipolar
17 Gateron Tactile Clear Clear top 3mm flat Warm White
18 Zealio 65g Clear top/bottom 3mm flat Orange
19 Zealio 78g Clear top/bottom 2x3x4mm Green
20 Cherry Clear 2x3x4mm Blue
21 Outemu Blue 2x3x4mm Blue
22 Kailh Blue 2x3x4mm Green
23 Outemu Blue RGB 2x3x4mm Blue
24 Gateron Brown RGB 2x3x4mm Green
25 Gateron Brown RGB 2x3x4mm Blue
26 Gateron Brown RGB 2x3x4mm Green
27 Gateron Brown RGB 2x3x4mm Blue
28 Gateron Brown RGB 2x3x4mm Green
29 Cherry Black RGB 2x3x4mm Blue
30 Cherry Tactile Grey 2x3x4mm Red

  • Gherkin 1.1 PCB with PCB top and bottom plates.
  • Green solder mask was sanded off of PCB plates.
  • Switches 24-28 are duplicates.
  • Milky white tops were dyed with regular RIT dye. 
  • Gateron tops can fit 3mm LEDs with flange.
  • LEDs mostly from eBay

Top view at low brightness setting

Side view from top

Holtite sockets for switches and LEDs

Wednesday, December 14, 2016

Pro Micro ISP

Nurse Ratched

  • Based on the Arduino as ISP sketch
  • For replacing the bootloader on a Pro Micro as described here
  • Spring loaded pogo pins for quick non-soldered connection to Pro Micro
Assembled from some protoboards, an Arduino Pro Mini and a USB/Serial adapter.
Could have just used another Pro Micro, but I had the parts.

The working end. Spring loaded pogo pins soldered in place, spaced to lined up with the pads on the Pro Micro.

The controller end with the Pro Mini and serial adapter. The Pro Mini is programmed with the Arduino as ISP sketch.

Hooked up and running. Pro Micro powered and programmed through the pogo pin connections.

Gherkin Sock

Waiting for someone to make 30% sleeves

These short tube socks work fine for now. Cheap too.

There are many sources of these types of socks, they take plain white socks and fabric print an image on them. You can have custom ones made online.

Gherkin and sock

Gherkin entering sock

Gherkin in sock

Gherkin trapped in sock

Tuesday, December 13, 2016

Controller Size Comparison

Number Type Dimensions PCB thickness Chip Pins Connector Example
1 Mattairtech MT-DB-U4 52.25 x 22.75mm 1.6mm Atmega32U4 ALL mini
2 Clone Pro Micro New Type 39.75 x 23.5mm 1.6mm Atmega32U4 18/20 with hack mini Stealth Quark
3 Clone Pro Micro 33.5mm x 17.85mm 1.2mm Atmega32U4 18/20 with hack micro Flanck
4 PJRC Teensy 2.0 30.6 x 17.9mm 1.7mm Atmega32U4 25/26 with hack mini Retro Planck
5 Pololu A-Star Micro 25.25 x 15.35mm 1.0mm Atmega32U4 18/20 with hack micro Atreus
6 DF Robot Beetle 22.4 x 20.4mm 1.1mm Atmega32U4 10 micro
7 Clone Digispark 23 x 18mm 1.6mm Attiny85 6/4 with USB micro
8 Clone Digispark Pro 27.1 x 18.3mm 1.6mm Attiny167 13/11 with USB micro
9 PJRC Teensy LC 35.7 x 17.95mm 1.6mm MKL26Z64VFT4 27 micro Van LC
10 PJRC Teensy 3.2 35.6 x 18.05mm 1.6mm MK20DX256VLH7 34 micro Van 3.2
11 STM32F103C8T6 53.5 x 22.9mm 1.2mm STM32F103C8T6 37 micro Planck STM32
12 Clone Arduino Pro Mini 32.75 x 17.7mm 1.6mm Atmega328P 20 none

Dimensions are measured from the actual boards and do not include the protruding USB connector.

The Pins that are "with hack" require removing existing indicator LEDs and soldering to tiny surface mount pads. On the Teensy 2.0 pin E2 can be accessed by soldering to the tiny pull down resistor.

"with USB" are indicating the loss of 2 pins for use with VUSB, since these board do not have native USB.

The Arduino Pro Mini does not have any USB connector. It can be used with an external VUSB circuit.

Top view

Bottom view, some have components on the bottom.

Side view to show relative thickness of boards