Adding RGB to FC660C with HASU controller

Thanks, guys! I’m curious to see if any PC heavy-6s show up with RGB before mine arrives. Also curious to see how the mounting hole in the plate plays with the light. Might end up having to cover it with electrical tape.

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When my polycarbonate case gets here man, this is absolutely happening. I can hardly wait. Both for the case and the glorious excess of RGB lighting.

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This is a really cool mod, I’m considering trying this mod out with my own U&B lol.
I do wonder if you think if the RGB mod is doable with the YDKB 660C BLE controller. To add, I was also wondering if the firmware changes are done to only change the RGB lighting/behaviors or if it is actually necessary for the RGB to light up at all?

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Hey, thanks for the interest!

The firmware changes are absolutely necessary. You’re taking a simple on/off indicator and repurposing it to output a value the RGB leds can read. It’s a relatively simple change in QMK. I don’t know much about the TDKB controller, but it looks like it uses to program it. Based on what I saw, I don’t know that there is a way to repurpose the insert pin as an RGB driver. Without being able to download the firmware and make edits to it, I’m not sure how I would go about adding support for the YMDK 660 BLE.

I welcome other folks chiming in - I’m sure there’s some firmware wizard that knows more about it than I do.

This project is awesome!

I ordered a heavy-6 in polycarb (hopefully it will arrive around the end of the year). Am debating Topre vs making an MX version like the 660c-x. I think I am leaning Topre with this mod and maybe the deskey sliders later on. Looking into the LEDs there are quite a few different options. I like your idea of going with less density to reduce the number of jumpers.

There are quite a few different LED strips:
What model led did you go with? (WS2812B/C & APA102/4 etc)
Related question does it have to be one of the QMK compatible ones?

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Thank you for the kind words!

This is the specific LED strip purchased (for a different project) and wound up using here. It utilizes SK6812 led, with a density of 60/meter

If I were to do it again, I’d probably go with something like this strip from digikey, or this strip (if you prefer a bezos link). If you wind up searching for your own, searching for a “5050 led strip” and “30 led per meter” will generally get you pretty close. Just be aware that many / most of the strips available appear to come with a waterproof coating, which really isn’t needed (and may even be a negative, if you have clearance issues).

And I would definitely stick to qmk compatible.

I, too, am hoping for my heavy-6 by year’s end, and am contemplating some des sliders once they roll out the 2u sliders. :smiley:


Thanks for getting back to me.

I think I am committed to trying the Topre route now. Managed to snag a Hasu controller from 1upkeyboards yesterday. They come in stock every once and a while but sold out in like 2 hours. Tracking down a lead on a used FC660c next.

The Amazon link had some nifty look right angle connectors. That might work if stars alight on the spacing to use. Even if it doesn’t I might still get this kit because it also has some 3 wire roll that is bound together. That should keep everything tight and clean like you have it.

Connector kit that seems promising:

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Ooh, I hadn’t considered the connectors - that could make it really clean.

Whenever you get the job done, don’t forget to update line 52 in config.h
#define RGBLED_NUM 16
My install used 16 LEDs, just adjust that number for yours and you will be set to go. I should probably also make sure the firmware repo is up to date with the latest version of QMK. :sweat_smile:


Oh man, I totally wish I’d have known about these connectors. They would save so much hassle.


Thank you @rooski15 worked perfectly excellent guide!!! Soldering on the connections properly was a little tricky but was able to do it in about 10 minutes.

I will pretty up the connection when I get the Heavy-6. Not sure if I want it coiled around facing out like this or on the bottom of the case facing up or the PCB facing down (depends on the light reflecting). Have the corner pieces too I can snap in also.


Nice work, Dave! I love it, excited to see it in the h6, and really curious to see how different mounting styles affect the RGB diffusion. :grin:

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Got me wanting to try it… and of course, they hasu controllers are sold out. RIP

I wound up ordering direct from HASU cause I couldn’t manage to find them in stock with 1up. Ordered 3 and shared with friends to reduce shipping, came out about the same as 1up.


good idea!

It will probably be a while until 1up gets more. They just got a limited stock last week I think, and noted that Hasu was having trouble getting the chips needed to make the controller boards.

I found Yang’s tmk repo, so it may be possible to alter the program and compile locally. Looks like there are other examples of RGB in that repo you could pull from.

I’d have to read up on TMK in order to do it, but again, potentially feasible.

Edit: Guide on building tmk

A few hasu controllers back in at 1up today.

Quick update to all interested (@Extra_Fox, @Dave, @pixelpusher); I’ve streamlined the firmware into a simple keymap folder that you can drop into an existing QMK repo (see original post’s edits). I’ve submitted those same files via PR to the QMK master, so hopefully anyone can enjoy them soon.

If any of you are QMK contributors and would like to test these changes, please do so and leave your feedback. Cheers!


So cool, man. I’m running the RGB via version. Granted… I don’t have any LEDs yet (LOL) but it’s gonna work like a charm. Now to get some leds!

I usually compile my qmk with the configurator, so I didn’t realize that they have QMK_MSYS now. Makes life a lot easier for sure.

My insert light just stays on now permanently. Is there a way to turn it off? I’m guessing there’s not since that’s where you are grabbing power and data, but I thought I’d ask. Perhaps I can simply desolder it :slight_smile:

@Dave did you have any progress using those angle connectors? I’m thinking about ordering the same kit as you

Ahh, that’s good to know that the insert LED stays on permanent in units that have one (mine didn’t). The answer is, yes, you can absolute disable that. Let me see if there is an easy solution in my implementation before trying to walk you through the underlying fix.