A 60ish keyboard with a new plate-case design. This has been heavily inspired by the layout of Purple Owl but I wanted a more programmer friendly right side with larger modifier keys. So I changed some keys and also redesigned the PCB to use a more standard QMK approach. With LED support and some good keycaps, I think it is a great looking compact keyboard!
The typing is damped by the felt layer but quite stable due to the pretty firm brass plate. The springs keep the plate in place but allow some flex as designed. Sound is really good for what I expected, but I added foam on the plate and without it the brass plate will be pingy with the missing support in the center.
TL;DR: Pricing and surplus parts listed at the end!
TL;DR 2: Some upcoming improvements listed at the end
- I will add some feet, no angle is just too flat too type. ETA unknown.
- Plates and weights have arrived, assembly finalized!
- Case assembled, only plate and weight left, ETA see below.
- Case parts have arrived.
- Plated ETA at 15/11, felt layer ETA 15/11, case parts also ordered with no ETA. Pricing see below.
- PCBs have arrived and tested good.
- Found plate manufacturer, plates and weight will be brass laser cut. Plate will have engraving. Cost listed below, comparably cheap for low amount of parts and a strong reduction in cost with more parts expected.
- Sourcing part manufacturers for casing.
- Case design finished.
- Ordered PCBs for Daughterboard and Keyboard.
- PCB design done.
The layout is somewhat odd. The aim was to have a good amount of modifiers and still keep the interesting stagger and a trapezoidal shape. This lead to the removal of the nav cluster, thus this is the initial lite version. I might create another one with arrow cluster and going for a parallelogram shape. Final layout ended up like this
Final assembly is described here in good detail with the parts I ordered for the first batch, if you make your own parts some steps might need adaption. Any question, just let me know!
With all parts produced, the case assembly comes first. See below for how I proceeded given the parts I had with just laser cutting. Bolts are M3 x 12. Keep in mind to install the daughterboard in between the case rings or just use two screws. Weight needs shorter bolts, M3 x 5 work or just cut down some longer ones.
I then added switch pads and plate foam to PCB and plate, since brass plates often tend to be a little pingy. I chose some generic KBDfans stabilizers which was a bad choice since they rattle. Next re-assembly, I'll change to some better ones.
Finally, assemble plate and PCB with switches (Tangerines linear):
Place felt on case and align, place plate with PCB, and screw down with a soft washer, spring (see below in parts table) and bolt using the same M3 x 12. Done! Just add some keycaps, I chose PBTfans Resonance. Base Kit and 40s are a good fit, sometimes base kit is enough, just need the split spacebars.
Plates and weights were laser cut but the first batch has issues with tolerances and surface quality. The engraving, especially, is barely visible. I tried to glassbead blast two samples which increased surface feel quality and produced usable samples. The engraving however vanishes. I have the leftover plates if someone wants them but keep those issued in mind.
Same for the weights - but they are invisible. So for those I just cut the two threads and sanded them down a bit.
Case acrylic parts have been produced. Cut quality is acceptable. This prototype is built with four layers just 2D cut, so some steps remain in creating the case: First, countersink the screw holes in the bottom (also, from the bottom side). I have a drill press, if by hand try to keep it as symmetric as possible. I then went on to cut the M3 threads for the six bolts for case assembly, which are only cut in the uppermost acrylic part. Pre-assemble two (in my case blue) top rings and cut five threads, M3, for plate from top. With only two rings you can cut the threads in an open hole and don't need to worry about the blind holes. Finally, assemble the four acrylic parts (bottom, frosted ring, blue ring, top blue ring). Place felt layer (in my case orange) on top. Some impressions:
PCBs have arrived and look quite cool. All features seem to work! Tested both FWs
and all buttons, LEDs and other features work as expected.
TL;DR No need to solder any headers and ISP, out of the box PCBs accept
initial firmware using qmk flash over USB! Thanks, ATMEL (I guess, but please
update your documentation!).
More informations? Keep on reading...
First thing I noticed is that I chose a 1.27mm spacing for ISP which I did not have around, so I had to fetch some headers. Soldering is quite annoying at that pitch but doable. Next up was an adapter for my ISP programmer which again was for 2.54mm spacing. Again very fiddly. Should've tested before to avoid some burnt fingers. Finally, solder RST switch at the front, thats quite easy.
For an initial check if everything is hooked up run
> avrdude -c usbasp -p m32u4
avrdude: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.00s
avrdude: Device signature = 0x1e9587 (probably m32u4)
seems good, check the fuses:
> avrdude -c usbasp -p m32u4 -U lfuse:r:-:h -U hfuse:r:-:h -U efuse:r:-:h
avrdude: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.00s
avrdude: Device signature = 0x1e9587 (probably m32u4)
avrdude: reading lfuse memory:
Reading | ################################################## | 100% 0.00s
avrdude: writing output file "<stdout>"
0x5e
avrdude: reading hfuse memory:
Reading | ################################################## | 100% 0.00s
avrdude: writing output file "<stdout>"
0x99
avrdude: reading efuse memory:
Reading | ################################################## | 100% 0.00s
avrdude: writing output file "<stdout>"
0xf3
avrdude done. Thank you.
Perfect, nothing to change here. Mind that JTAG is on but that should not be
of an issue here. Go ahead and flash the firmware (just use production, which
includes a bootloader!)
avrdude -c usbasp -p m32u4 -U flash:w:11kbd_hedgehog_lite_default_production.hex
avrdude: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.00s
avrdude: Device signature = 0x1e9587 (probably m32u4)
avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed
To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: warning: cannot set sck period. please check for usbasp firmware update.
avrdude: reading input file "11kbd_hedgehog_lite_default_production.hex"
avrdude: input file 11kbd_hedgehog_lite_default_production.hex auto detected as Intel Hex
avrdude: writing flash (32768 bytes):
Writing | ################################################## | 100% 8.60s
avrdude: 32768 bytes of flash written
avrdude: verifying flash memory against 11kbd_hedgehog_lite_default_production.hex:
avrdude: input file 11kbd_hedgehog_lite_default_production.hex auto detected as Intel Hex
Reading | ################################################## | 100% 7.41s
avrdude: 32768 bytes of flash verified
avrdude done. Thank you.
Perfect, you can test the PCB now and / or test the bootloader by flashing a new firmware using QMK (after copying the folders or running from the repo)
qmk flash -kb 11kbd/hedgehog_lite -km default
All works! If you want to prevent changing the FW, just open the slide switch and any reprogramming will be disabled.
Daughterboards just work out of the box - nothing to add here. Building the cables, however, is an issue. First, I tried to crimp them myself but even with the smaller pliers I did not manage to have a good reproducible result. I then just bought single sided cables and soldered the wires using two ends. Not pretty but works, and if you look at some shop offers online, it does look to be an often used workaround.
I did find a custom cable shop in CN which can produce the cables for around 0,40€ per cable but they start at 100pcs so this wasn't a good option here. Maybe if some group buy will run at some point, I will follow this route. For now, !no cables are available from my side!
The PCB is a basic QMK capable ATmega32U4 row-col setup, using 9 rows and 9 columns. The PCB was designed in KiCAD and the current design is somewhere between WiP and ready for a prototype. Cool features include a good number of underglow (15) LEDs and some flex cuts. Switch sockets are hotswap and layout is a single fixed one, derived from ANSI. No stepped caps or any splits at this point.
The USB connection is a JST with support for Unified Daughterboard by ai03 which make the PCB able to move and flex and saves some space. Also, feel free to adapt the case to place the USB wherever you want.
There are, compared to other PCBs out there, some smaller quirks and features which are notable:
- The PCB uses a M-variant of the AtMega due to shortages and prices hikes of the more common A-variant. Also, this one is a little more compact.
- The implemented M-variant has no USB bootloader flashed. Initially, this has to be done (or not see above). Using a basic ISP programmer, check the fuses and if needed set them to the QMK values (which are good for external oscillator). Afterwards, USB flashing using RST over USB should work (confirm that HWB switch is closed!). See assembly section for details!
- LED power supply is activated with a solder jumper. This reduces current during initial flash and allows to leave LEDs disabled in non-translucent cases.
- HWB pin is connected with a switch. So by either not soldering this in or setting to open position bootloader access and flashing can be preventing and also reducing startup time / room for errors. A jumper exists to fully override the switch.
- Reset switch is placed on bottom ("top" during use) layer below spacebar so resetting can be done with case fully assembled.
The above should make it clear that even with an assembled PCB minimal soldering is required for full functionality. I will only have one PCB side assembled to save money - so when using this procedure or leftover PCBs. I might offer the reset switch has to be placed and soldered afterwards to allow bootloader flash.
Case will be designed for either laser cutting or printing / milling. Currently, the case is layered for cutting so some cutouts aren't perfect but milling is not feasible in prototyping and small batch. Current color design is frosted bottom, blue mid, warm yellow felt and brass plate. Overall height will be 16.5mm to plate surface. Feets are optional and might get added to tent the whole case.
Bottom and three rings (one acrylic, two blue, split not visible in render) will be screwed from below. Plate will be screwed from top into preassembled bottom.
Plate is designed to be aluminum or brass, and the plate mount is done via a felt / cork dampening layer and springs. Plate logo is optional depending on engraving capabilities of specific shops.
Initial CAD renders below showing top, spring mount in comparison with switch size and the connector which is currently placed at the left side.
Because its autumn and that's the perfect time for them!
Obviously, this is a prototype / small batch so pricing will a) comparable high and b) differ in different locations. Also, due to my profession, I do have some connection which make some of the steps easier. Cost is listed for an order of (at least) five keyboards. Second to last column shows parts which are surplus (contact me if you are interested!)
| Part | Produced by / at | Price | # available | Remark |
|---|---|---|---|---|
| Main PCB | JLCPCB assembled | 35€ | 3 | One side assembled, RST switch and jumpers need soldering, parts included. |
| Unified Daughterboard (with cable) | JLCPCB assembled | 10€ | 3 | PCB is 1.2mm for increased spacing! |
| Brass plate 1.5mm | Local shop | 35€ | 3 | Price includes engraved hedgehog and basic removal of burrs. Might glassbead blast it later for satin looks. |
| Brass weight 2mm | Local shop | 10€ | 3 | Only two millimeter due to material availability - will add some weight and looks! |
| Case lower frosted acrylic | Local shop | 25€ | none | No discount for multiple parts |
| Case mid colored acrylic | Local shop | 35€ | none | No discount for multiple parts |
| Felt damper | Local shop | 8€ | 3 | |
| Springs | Local shop | 2€ / pc. | 6 | I choose 6mm free length and compress them to approx. 3mm which generates 3N per spring. Inner diameter should match M3 (>3.5mm) and outer should not be much more than 5mm |
| Hardware | Local shop | - | - | M3 x 12, M3 x 5, Nylon washers M3 |
- Improve GND on PCB for controller. Not needed since it works really good but better practice
- Improve plate manufacture or / and increase switch opening size. The current dimensioning is ok but fairly tight.
- Do the same for the stabs, if possible add at least 1mm left / right for the stems
- Find a way to keep the felt layer aligned, currently it tends to slide around a bit - purely a visual error but still needs improving.
- Add some more layout options: Switch BS, Mod key right of return, ISO?