Hybris - A wireless 104 key keyboard from scratch

[pomk]

Just be sure to check that your printer is accurate as well. I usually add a 50% opaque ruler in such printouts to rule out scaling issues.

[senso]

How the keyboard going?

Everything OK with you Richard?

[RichardH]

Just a quick update! I've been working on techno recently, so the keyboard design took the back seat last month. I got back into it the last few days and placed the diodes and encoder. Next step will be to place the logic components and power supply. I'll try and describe the hows and whys on that next. I went through and measured everything twice and it looks like everything should fit the first time. I placed the diodes so there was a good bit of space around the drill holes. Other than that, it's boring, methodical work.





-Rich

[RichardH]

Big progress! I finally got some time to finish routing and I've sent the board off to the fab! 

I'll go through some of my routing decisions.

The component side of the board (numpad on the left) board was split up like this:



USB signals were routed first since they're really the only high speed thing on the board. I followed the chip vendor's PCB prints here https://www.ftdichip.com/Support/Documents/PCBData/NerO%20PCB%20Prints.PDF and tried to length match the differential pairs  to 5mil. This will definitely be an annoying area to hand solder due to the density of the parts. I chose fairly big footprints for the passives at 0805 packages, so I'm confident it'll come together.




Next came the Bluetooth MCU. The Bluetooth module was placed right on the edge of the board above the numpad. I kept the crystal close to the module, and as far as I could get it from the other signals. The space was pretty constrained, so I ended up killing a bunch of test points in order to make all the parts fit and still leave a ground keepout zone under the antenna. The rotary encoder is mounted just to the right and the signal lines are pretty short. Since the serial lines are really slow, I routed then wherever they fit later in the layout process



The column layout and diodes were next. I picked a spot and roughly placing the diodes in the same place for most of the 1u switches and did the 1.25/2u ones a little more custom. I'm a little disappointed in the shape of the traces, but this was a good learning experience for what to do better in Rev 2.   



I placed the shift registers next. The data direction ended up being opposite to the breaboard mockup, which ended up making the connection go from the MCU to the register nearest the spacebar. Instead, the data line now goes from the MCU to the register nearest the numpad and daisy chains to the arrow keys then to the spacebar area. I also tried to make the traces not go directly under the stabs, just in case of wear. Any traces routed through the stabs were pulled as close to the mounting holes as possible.



Lastly was the power supply. I was running a little short on space with all of the signal traces, so I picked a convenient spot under the F12 key. Since this will be the highest point of incline, it will let the main board to lay just above the battery inside the case. I'm going to design for a 2000mAh battery, so 60mm x 36mm x 7mm will be the allowance. I've used some fairly beefy traces on the VCC rails just because they have so damn long to go.

I added some more mounting holes to the board after routing all the signals and pulled back the ground plane from all of the holes. That concludes the PCB layout! I'm expecting the boards to arrive as early as tomorrow!

-Rich

[marhalloweenvt]

I just want to say that Your work is very amazing.
Would you allow me to use your design for my design?
Thanks

[RichardH]

@marhalloweenvt by all means. It's open source hardware. Hack away

The PCBs come tomorrow, so I should have some assembly stuff to show off.

-Rich

[marhalloweenvt]

Can't wait for coming home to do some prototype with your design. I have some nrf52823 modules lying around.

[RichardH]

Happy new year everyone. It's been almost a year since the project started and I'm now at a fully built PCB!

Rev.1 of the PCB had a number of problems:

• The Switch spacing ended up being 19.05mm, the printer was scaling as suggested by a previous poster - moral: never trust printers
• The USB protection diode had too much skew and ended up fouling the signal- I've dropped it for now
• Pull up and down resistors were not needed on the Jlink connector

So I've spun a Rev.2 and now the switches fit the plate and the minor signal issues were resolved

Here's some photos from the build - it was hand soldered minutes before these photos were taken, so it's a bit blobby and flux-y:


USB Section





BT module





Battery Section




The bottom side of the board




Thanks for all the help and feedback, guys! I'll follow up with a post on the progress of the case and hopefully get to building the plate and switches soon.

-Rich

[marhalloweenvt]

You're rock.
Do you think about add some underglow RGB led? That should be nice future

[iaman]

This rules, Rich! Glad to see folks doing work on full-size PCBs, finally.

[vvp]

Do you think about add some underglow RGB led?

LEDs would have quite a bad impact on the battery life when switched on.

[RichardH]

Hey again! So today I want to share my case design so far (been working on it during the holidays). First I'll follow up on the LED qustion above. I left the two wire interface open with solder pads on the mcu in case I decide to do that It would need a much bigger battery or to only run lights while on USB. I'm designing the case to support up to a 2000mAh battery, which would run bright lighting for about a day (@ 70mA or so). I guess the other issue is I wanted the base to be black.

So here we go:



My design goals here:

• A metal case top, likely natural color anodized aluminum
• A metal knob for media controls
• A vinyl or silk screened decal in the top right corner
• A plastic base - probably 3d printed to allow a large bluetooth aperture
• A switch on the bottom to physically turn off the board when not in use
• Room for a fairly large capacity battery just in case

I've done laser sintered nylon (SLS) through shapeways before and I liked how it came out. I'm not sure if that's the latest tech these days. The aluminum upper housing might be very expensive as designed due to the cavities on the bottom (the  plate is one level and the top right is another) and I want to cut the back of it up a bit to cause as little signal loss as possible. I'm not sure which bumpons to use, are they normally recessed? I'd love some manufacturing tips if anyone's done this before.

-Rich

[hottrout]

I love what you are doing here and am following very closely.  Can I just say as a man the same age, I loved Hybris on my Amiga, it is one of my all time fav games from one of my all time fav systems.

Do you still game?
Do you collect Amigas/Computers?

[RichardH]

Heh.. I still play most of my favourites on uae - it’s close enough when using a game pad. My friend has my A1200, so I know where to find it waiting to see more about these vampire boards, too. There might be a little retro computing in my future if those turn out as advertised.

-Rich

[RichardH]

So it's time to build! All the internal parts have arrived and I now have enough to build the plate and switches.

The mechkb universal plate I'm using just needs the top tab sawed off to fit the encoder and status leds.



This plate also uses plate mount stabs, so I did a little test fit and installed all the stabilizers. I put a bunch of lube on the ends of the wires and the sides of the housings.



I originally started the project thinking I would use MX browns, but through a twist of fate I ended up with some bags of zilents so 62g zilents for the alphas and 65g for mods/numpad/f row/space



Lubed the side rails, the lower spring mount and a touch on the lower "pin" of the switch




After putting in the anchor switches, I populated the rest of them



Keys, encoder and aluminum knob and battery all installed. using a little cloth to keep the battery connector from hitting the table.



I'm now typing this message from my new board using Bluetooth So happy with how it turned out - Zilents are a dream! Plastics will come probably next month so I'll have a full prototype. If the plastic version looks good, it'll be onto the metal case top.

-Rich


 

[iaman]

Rich, that looks great! So excited to see this project get here!

[AGmurdercore]

I was searching around to gather ideas on a wireless build and I stumbled upon this thread. Any update on this, how are you liking it after some time now?

[RichardH]

Woops missed this It's my primary board now and it's been a workhorse. The nrf52832 version of this board is now obsolete, so I think if I were to go back to this project, I'd look at integrating the Nrf52840 version instead. Adafruit has already made an SDK avaiable. I have issues with the 840 though because the module is no longer hand solderable. It does use a lot less power and no longer needs the UART. About 2 years later I still get a week of battery life on a 500mAh battery. I was hyped about building a case for it, but the price is just too much, so I just use it as a bare board still.

-Rich