PCB Help

[MostProvolne]

im new to the custom keyboard world but im looking to build my first keyboard. i wanna build a 65% kbd but i want a pcb thats capable of supporting underglow lighting but also rgb back lighting. i also liked the idea of hot swapping. but im not sure if thats even possible or if im putting too much on my plate for my first build. thanks in advance for any help or insight.

[user 18]

As far as I know, most PCBs can support hot-swapping, it's just a matter of soldering in the SIP sockets where you'd normally solder in the switches. Then, you can mount the switches in the sockets without soldering.

I don't know how many 65% PCBs are even out there that support RGB backlighting -- to my knowledge, that either requires surface-mount LEDs behind the switch, or substantial modification to allow four-lead through-hole LEDs to be used. That'll probably be the sticking point. Unfortunately, I don't know of any such boards off the top of my head.

[Kevadu]

The Massdrop Alt sounds like exactly what you want expect it's not available as a kit and it's not available at all yet.  You would have to wait for the next time it drops or get it secondhand from somebody once the first run is released.  But it has all the features you're looking for, even hot-swapping.

Note that having both hot-swappable switches and backlighting necessitates SMD LEDs which the vast majority of PCBs of any form factor don't support.  This is because traditional LEDs in MX-style switches are mounted over the switch top.  So you would have to desolder the LED before you could even think about removing the switch.

There are a few 65% PCBs that support underglow lighting.  The YD68 and Clueboard for example.  These don't have per-key backlighting though.  They don't natively support hot-swapping either, though it's possible you could modify them with holtites or something.  But I would recommend doing a little more research on that first.

[Leslieann]

65% is a common size, I’m kind of surprised no one has a pcb with RGB top and underglow. Though underglow is relatively new, only works on certain cases and sockets, well.. read on.

My advice, start with one with rgb backlighting. You can probably add hot swap or a universal plate (better in my opinion) and add underglow to that either through a firmware change and a couple wires or a secondary controller (underglow is relatively simple compared to designing a pcb).


Here are a few to look into, but read what I wrote below because your goals may change.

LFK offers a 65% board with rgb underglow, hot swap, but only single color backlights
Winkeyless and Sentrac offer 65% with rgb underglow, you can probably add sockets.
The Z70 Pro has rgb top and hot swap but no underglow, which could easily be added.
Zephyr has all but underglow and sockets




If you still want to DIY… I've been doing a lot of research on this recently...
You will need serialized rgb lights (individually addressable leds). This is easier than it sounds and only needs a single wire to the controller to manage them all. The bottom is easy, you only need about 5 -10 lights tops, but on top,  but for the top lighting it means an extra wire to every socket. Underglow can even be added without tapping into the controller at all. However, underglow is useless without a case that lets it shine through, and those are pretty rare.

Also, all those lights will need extra power and can over power most usb 2.0 connections. Even a fully lit keyboard using normal backlights can have problems getting enough power depending on the computer or port used. You may need a powered hub and/or use a usb 3.0 port in order to carry enough juice, by which point the usb mini connector may not be capable of flowing enough current. This is why some type A to type C usb cables are dangerous, they can ruin the usb connector by drawing more power than the port can handle. LEDS draw a lot more than you think when you have this many  and usb provides less power than you thing, more than that, RGB needs 3-4 times the power of a single color led (depending on color).

Not all pcb's can support hot swap, it depends on the hole size as the socket has to go up through the hole from the underside. There are definitely some pcb's that do not support them, KBDfan75 is one of them. They also hang down a bit and on some cases (like the older Vortex Filco case) would probably rub the case. Also, keep in mind, (at least some) hot swap sockets are only rated for 20 insertions and will pose a risk of poor connection. If you use a plex or plastic case, case flex can also cause flex/wear or complete disconnections of switches. A better option is to just have removable tops, i.e. universal plate.

If you go any more than 68% the Arduino Pro runs out of adresses without an add-on board.

If you use normal leds, hot swap will not work on all switches, even with sip sockets as the led passes through the switch and the sockets will catch. Learned this one the hard way. Still handy for led swaps. If you need to use normal leds, you want a switch with a large led hole, or a clear housing with the lights underneath (SMD).


Still want to DIY?
There are some handy tools out there to help (keyboard layout editor, Swill’s case builder, and Kalerator) and people have done a lot of the legwork on doing it (check TMK firmware on github). However, you can’t do all of it with free tools as far as I can tell.  Eagle Cad free doesn’t support pcb’s large enough for a keyboard to check the work and make changes. Also, expect more than a few revisions, and you often have to order more than one pcb. While the final product can be cheap, getting it all done right may not be.



Edit: Kevadu covered some of this while I was researching something.

[MostProvolne]

so if i go with the sentraq 65% pcb. as long as i soldering rgb backlight i should be able to have underglow and backlight correct?

[Leslieann]

You are confusing underglow and backlights.

Backlights are in/under the switch, underglow is under the pcb. You are not going to add RGB backlighting easily, if at all, to any keyboard. Underglow can be as simple as tossing in an rgb light strip into the case.

[user 18]

so if i go with the sentraq 65% pcb. as long as i soldering rgb backlight i should be able to have underglow and backlight correct?

You mean this one? https://sentraq.com/collections/parts-1/products/65-rgb-underglow-pcb

That PCB supports RGB underglow. It supports through-hole backlighting for two-pin (i.e. single-colour) LEDs. If you want to control the colour of your RGB LED, you will need at four pins on your LED for a basic setup (one pin each to control red, green, and blue channels, and a common ground pin). Setups also exist for individually-addressable LEDs in arrays that are a bit more complex (Leslieann gave a great summary just above), but I'm not aware of anything that's less than 4 pins for each LED in the array, and it would be a real mess to mod a standard 2-pin LED PCB to support those.

Two-pin RGB LEDs do exist; but all the ones I've seen oscillate between colours automatically -- i.e. you can't pick a colour, and you can't even guarantee that all your backlights will be the same colour at the same time.


What you should look for is something that already has surface-mount RGB LEDs. Take a look at the zephyr (https://zealpc.net/products/zephyr) -- the fourth-last to second-last pictures all show the PCB. You can see four-pin surface-mount LEDs already soldered in. That's the hardest thing to do yourself, so as Leslieann said, that's where you should start, by finding a PCB that has those. I honestly don't know of anything available right now that lets you just buy the PCB, rather than a kit.

That type of LED will also limit you to switches that support surface-mount LEDs. Take a look at the RGB series switches by Cherry: http://cherryamericas.com/product/mx-series-2/ (not all the switches here are RGB series, just the ones with clear casings). This severely limits the number of switches you'll be able to hot-swap anyway. You may find it easier (and a better experience) to get a plate with switch top cutouts, and rather than hot-swap switches, you can pop the switch top off and swap out the spring and slider. Any switch with an opaque housing won't work with surface-mount RGB LEDs, which, as far as I know, is the only type of RGB LED that any board currently supports.

E: got beat to the punch, but posting anyway, in case it's at all helpful