https://github.com/wirehead/edge-key-seventeen
A 17 key numeric keypad with encoders
https://github.com/wirehead/edge-key-seventeen
Last synced: 4 months ago
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A 17 key numeric keypad with encoders
- Host: GitHub
- URL: https://github.com/wirehead/edge-key-seventeen
- Owner: wirehead
- Created: 2022-07-03T23:28:37.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2025-05-03T21:34:01.000Z (about 1 year ago)
- Last Synced: 2025-05-03T22:24:57.164Z (about 1 year ago)
- Size: 1.4 MB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# edge-key-seventeen: A 17 key standard-layout numeric keypad plus encoders
I like numeric keypads. They come in handy when I am working with CAD packages and stuff. So you can see this as a piece of quiet rebellion against the world of hipster 40% or 60% fancy keyboards but one that still gives you a durable, fancy, interesting, artisanal, hand-crafted, mechanically-keyed product at the end of it.
## Prior art
This is partially developed using [Ruiqi Mao's Keyboard PCB guide](https://github.com/ruiqimao/keyboard-pcb-guide) as a reference... except that I'd suggest you don't actually use that guide as a reference because it's got some inaccuracies and at this point is old and unmaintained. It turns out that, because I was designing it around parts that I already was comfortable with using and based it off of prior designs, I'd managed to sidestep all of the problems. The current hotness is arguably the [ai03 Keyboard PCB](https://wiki.ai03.com/books/pcb-design) guide which seems to be newer and more accurate.
Otherwise, this has design lineage through a few earlier designs I cooked up but won't bother posting because they were mostly design experiments and aren't really useful for anyone.
## The design
### Design goals
* Be mostly standard in being designed for the QMK firmware, use Cherry MX keyswitches and standard-sized keycaps, etc.
* Contain the 17 keys of a numeric keypad, plus maybe some encoders for the funs.
* Look vaguely interesting as just a PCB.
* Use parts I already had in my parts bin for other projects.
### Concrete technical spec
* 17 keys in the standard layout so you can use pretty much any standard-layout numeric keypad caps.
* 2 rotary encoders with push-buttons.
* ATMega32u4 processor
* USB-C port
* Extra ESD protection diodes and a polyfuse for durability
* Programming port that you shouldn't actually need to ever use.
* 9 4-pin SK6812 "NeoPixel" RGB LEDs pointed downward for underglow
* 6 M2.5 mounting holes
* Not quite able to fit in the 10cm x 10cm box because of the size of the keys.
* Puns on the silkscreen
### USB protection
I did a bunch of digging and datasheet reading.
Given that I'm plugging this into the USB port on my computer, I tend to go for safety. Thus, there's a ESD diode to protect the USB lines from spikes, there's a polyfuse on the power line so it won't use too much power, there's the required capacitors, and there's a decoupling network to keep the EMI from the cable sheath from crossing over to the ground plane. This is more than most of the development boards.
I also added a polyfuse in case you short power to ground so it will reduce the chances that things go really bad.
### Routing scheme
Col: PF0, PD4, PD5, PD3, PD2
Row: PB6, PC7, PC6. PB5, PB4
Encoders: PF5/PF6, PF1/PF4
Col -> Row
Neopixel: PB7
Numlock LED: PF7
## BOM
|Reference |Quantity |Value |Footprint|
|------------|-----------|-------|---------|
|C10 | 1 | 4.7 nF | 0805 |
|C1,C2 | 2 | 22 pF | 0805 |
|C3 | 1 | 10 uF | 0805 |
|C4 | 1 | 1 uF | 0805 |
|C5,C6,C7,C8 | 4 | 0.1 uF | 0805 |
|D1,D2,D3,D4,D5,D6,D7,D9,D10,D11,D12,D13,D14,D15,D16,D17,D18,D27,D28 | 19 1N4148 | SOD123 / Axial |
|D19,D20,D21,D22,D23,D24,D25,D26,D29 | 9 | SK6812 | 5050 PLCC4 |
|D30 | 1 | 5mm LED | |
|D8 | 1 | PRTR5V0U2X_215 | TO-253-4 |
|F1 | 1 | 500 mA Polyfuse | 1206 |
|H1-H6 | 6 | Mounting Hole | M2.5 |
|J1 | 1 | MicroUSB | GCT USB4085-GF-A |
|J2 | 1 | AVR-ISP-6 | 2x03 2.54mm pitch vertical SMD |
|MX1,MX2,MX3,MX4,MX5,MX6,MX7,MX9,MX10,MX11,MX12,MX13,MX14,MX17 | 14 | Cherry MX |1U |
|MX8 MX15 | 2 | Cherry MX | 2U Vertical |
|MX16 | 1 | Cherry MX | 2U Horizontal |
|R1 | 1 | 1M | 0603 |
|R2,R3 | 2 | 22 | 0603 |
|R4,R5 | 2 | 10k | 0805 |
|R6,R8 | 2 | 5.1k | 0603 |
|R7 | 1 | 1 M | 0603 |
|R9,R10 | 1 | 330 | 0805 |
|S1 | 1 | Toggle switch | C&K KSR223GLFG |
|SW1,SW2 | 2 | Rotary_Encoder_Switch | PEC11R-4215F-S0024-0-0-0 |
|U1 | 1 | ATMEGA32U4 | TQFP-44 |
|Y1 | 1 | 16 MHz | HC49-U |
## Construction
The gerber files are as I upload to JLCPCB to be fabbed.
If other people start wanting to try and fab this board, I'll write an actual proper assembly guide. :)
Either way, the important points to consider are:
* Everything should be solderable with a regular old temperature-controlled ESD-protected soldering iron.
* You don't need to populate J2 unless you get yourself in deep trouble.
* The keyboard diodes are hybrid footprints that can use either a SOD-123 surface mount diode or an axial one. I actually find SOD-123's easier to solder all told but I'm probably at least a bit odd.
* You can use either PCB-mount or plate-mount keyswitches and there are holes for PCB-mounted stabilizers.
* You can use a set of Mill-Max 7305-0-15-15-47-27-10-0 maybe the new 3305-1-15-15-47-27-10-0 receptacle connectors so that the keyswitches can be hot-swapped -- The 3305-X series is a new part specifically designed for keyswitches.
### Initial bootstrapping
You should just be able to program a freshly constructed board to the USB port and use the QMK programming tool to put an appropriate firmware on the board with the default bootloader.
I need to actually submit the upstream patches for QMK.
### Mounting holes
There are 6 M2.5 sized mounting holes in semi-convenient locations.
### Chassis design
This will appear later, still working on it!
## Changelog
### v1.0 rev 1
### v1.0 rev 2
* MicroUSB replaced with USB-C
* RS-187R05A2-DS button replaced with KSR223G LFG
* RG-49 Crystal a 3.2x2.5mm SMT
* KiCAD 6.x instead of KiCAD 5.x
### Things I would change next time
* I might try to trim a few mm off of each of the edges.
* I might remove the hybrid SOD123/Axial feature because I actually solder SOD123's faster than I solder axial parts these days.
* The programming port is kinda annoying in the layout and I guess I need to look at more alternatives in the rare case you need to bootloader it.
## License
[](https://creativecommons.org/licenses/by-sa/4.0/)