Kryptonite

Gherkin with bright green backlight

• Green kryptonite
• Gherkin

 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.

Germanium Diodes

Gherkin with germanium diodes

• Gherkin PCB
• Vintage Russian D9K (Д9К) Germanium detector 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

Daruma

GNAP 2.0 with G20 keycaps

• Daruma
• GNAP 2.0 PCB
• Plateless PCB mount switches
• 3mm stainless steel bottom plate from Lasergist.com
• 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.

Rainbow Pickle

Gherkin with WS2812b RGB LEDs

• Gherkin PCB
• Gherkin PCB plates
• Modified TMK with WS2812b enabled

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 EasyEDA.com
• 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.

Dyeing PCB

Dyeing a bare FR4 PCB plates

• Gherkin PCB top and bottom plates
• 3M 220 grit wet/dry sandpaper
• iDye Poly Purple dye
• Cheap stainless steel pot (never to be used for food)
• Boiling water 

Sanded off the green solder mask down to the bare fiberglass board. Looked like this http://www.40percent.club/2016/12/gerkin-tester.html 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.

Gherkin Assembly

A note about the license the Gherkin is released under.

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: https://www.youtube.com/watch?v=fq8A95AQFYU
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. http://www.40percent.club/p/socketing-pro-micro.html

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.

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.

2 Keys

Two key PCB

• 1.2mm thick PCB
• Pro Micro
• Holtite compatible
• Per key LED control
• 19.05mm spacing 
• PCB Gerbers here
• How to order PCBs from Gerber files 

Tiny board that sits on top of a Pro Micro and supports 2 PCB mount MX switches. Could create a tiny sandwich case for it using http://builder.swillkb.com/

The switches are connected to pins 2 and 3. The LEDs are connected to pins 9 and 10.

G20 keycaps on Gateron Yellow switches

Stuck to the front of my computer with a 3M Command removable adhesive strip.

Side view. The plastic spacers from two headers were combined to get enough height.

Holtite sockets stick out very far below the PCB.

Very little clearance between the Holtite and the USB connector.

Bottom of Pro Micro. Header pins were cut flush with bottom of PCB.

Holtite sockets for switches and LEDs.

Switches removed

Another built with a DIP socket making the Pro Micro removable. This one is without Holtite sockets.

PCB bottom

PCB top. Two resistors for the LEDs.

LED on while key pressed.

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