Monday, November 13, 2017
Gherkin Of The Week #7The "Massdrop" Gherkin. All 2U POS DSA keycaps from PMK grab bags.
"A strange game. The only winning move is not to play." Joshua (WarGames 1983)
30% with only 15 keys.
Each POS style key cap covers 2 switches.
Soldermask sanded off the bottom, exposing the copper layer.
Wednesday, November 8, 2017
More Russian DiodesGot a few more Russian diodes from eBay. There is very little documentation available for these. They are popular with retro audio electronics tinkerers. For the purposes of a scanning switch matrix just about any kind of diode will work. I purchased these just for their looks.
I removed the colored bands on some in this post. The glass is brittle compared to modern 1n4148 glass diodes.
I believe these are D9K, D9J, D2D and D9B. They are all NOS Russian diodes.
Monday, November 6, 2017
Gherkin Of The Week #6Another Gherkin using left over parts from the 30% Edward. This one uses the plain PCB top, not sanded or dyed. The keycaps are SA profile from a PMK grab bag.
The 30% Edward plates have TOMATO on them. These got sanded off on previous version that were dyed.
PCB middle pieces. These have white soldemask, but you can't really tell from the side.
You can see the supports for the last middle piece through the bottom PCB. These would normally be cut off before being used.
Extra thick with 12mm spacers.
Monday, October 30, 2017
Gherkin with Cherry ML switchesSame PCB dimensions as the regular MX Gherkin PCB. Cherry ML switches are PCB mount only, the Gherkin top and bottom switch plates are not compatible with this PCB. The ML switches are centered and have the same 19.05mm spacing as the MX switches.
The matrix is the same as the original Gherkin, it can use the same firmware, there are no LEDs.
The keycaps and switches were recycled from a PLUM ortholinear keyboard. PLUM keyboards can still be found on eBay.
Gerber files are on github.
ML switches are very small. Most ML keyboards use 18mm spacing. The Gherkin ML is using the same 19.05mm spacing MX switches use..
Bottom of the PCB with socketed Pro Micro clone.
PLUM keycaps. They are ABS with laser legends. 18mm spacing would not work well with these keycaps, they would rub against each other.
Side view with 6mm M2 spacers. A second PCB is used as the bottom. It would be possible to use shorter standoffs if you use a very low profile socket for the Pro Micro.
USB connector end.
Thickness compared to a MX Gherkin built with the same size spacers.
Wednesday, October 25, 2017
144 keys on an Arduino MicroThe Arduino Micro (not the Pro Micro) has 24 usable data pins. With this you can make a 12x12 matrix.
Two of the pins on the Arduino Micro are connected to LEDs (PB0 and PC7 used as indicators when used with the Arduino IDE). This may cause problems if using them as inputs, as outputs they should behave normally in a switch matrix.
The PCB is very basic, I used the reversible switch footprints so that the board can be flipped and the Arduino Micro installed right side up or upside down depending on which way the board is oriented. Having the Arduino Micro on the left allows access to the reset button.
The largest matrix you can do with a Pro Micro with its 18 pins is 9x9, 81 keys. I made a handwired one here.
unquadquad gerber files on github. Firmware.
DSA keycaps. Not really sure of what the layout will end up being.
Bottom of the populated PCB. Lots of standoffs.
Using a clone Arduino Micro. This one is a total redesign. The pinout is identical, but it has components on only one side and is much more low profile.
144 Gateron clear switches.
6mm M2 spacers and screws. A genuine Arduino Micro is much taller and would need taller spacers.
Bottom blank PCB with 3M bumpon silicone feet.
Monday, October 23, 2017
Gherkin Of The Week #5
Russian GherkinUsed old Russian germanium diodes. The top is a silkscreen less black PCB, bottom is a silkscreen less white PCB.
After scrubbing the PCB with 91% isopropyl alcohol to clean off the flux, some of the colored bands on the diodes started to come off. I soaked it in alcohol and scrubbed it some more and got most of the bands off. The clear glass diodes now look like little light bulbs.
Outemu Ice Grey switches from Switchtop. These are one the few new types of switches available in PCB mount.
M2 spacers and screws. Outemu switches came with sockets.
Blank white bottom PCB.
Outemu switch removed. You can also see the clear glass germanium diodes with their colored bands removed.
Thursday, October 19, 2017
Germanium diodes with their paint markings removed91% isopropyl alcohol will weaken the bond between the glass and the paint. A little rubbing and the colored rings will come off.
I have a few dozen diodes soaking in a bottle of 91% isopropyl for over a week now. The alcohol is now a light pink color but the bands are still intact on the diodes. So the IPA will not completely dissolve the paint, just loosen it.
I suspect some other types of solvent will completely dissolve the paint markings without having to scrub them off. Will experiment with acetone and whatever else the hardware store has.
An original red banded diode and two bare germanium diodes. 1n4148 diode for comparison.
Tuesday, October 17, 2017
Green Arduino Micro CloneThe Arduino Micro has 24 usable i/o pins, as many as on a Teensy 2.0. Same ATmega32u4.
Not a Pro Micro, a Micro. There is an official Arduino Micro. This is a redesigned clone I found on Aliexpress. It shares the same pinout, but has all of it's components on the top of the PCB. The bottom is completely flat. It also comes without the ISCP header installed and uses a smaller reset switch. Very low profile compared to the official Arduino Micro.
You can find these on Aliexpress by searching for CNT-013. They are also very cheap for what they are. Currently $3.50 each plus shipping, that's the same price as the smaller Pro Micro clones. Most other Arduino Micro clones are selling for twice that price.
Like the green Pro Micro it has a simplified power supply. Otherwise it should work just like a genuine Arduino Micro.
Low profile with a smaller reset switch than what is used on a genuine Arduino Micro.
The bottom has no components. The genuine Arduino Micro has the power supply components on the bottom.
Monday, October 16, 2017
Gherkin Of The Week #4
Black top 30% EdwardAnother variation on the 30% Edward. The top plate was sanded down and dyed black. The bottom is an experimental perforated PCB.
Translucent black keycaps from Flashquark.
M2 spacers and screws.
Perforated bottom plate.