We get a lot of inquiries on a regular basis, and it's blindingly obvious (pun clearly intended) that most of you are most interested about backlighting. In this post, I'm about to write everything you ever need to know about UHK backlighting.
First off, let me make it clear that currently we don't offer a backlit UHK version. The reason is that right now, we're solely focused on delivering the (non-backlit) UHKs, palm rests, and modules to our awesome backers. Everything else will follow afterwards.
On the bright side of things (pun clearly intended again), you'll be able to transform your non-backlit UHK to a backlit UHK by soldering LEDs to the circuit boards, and optionally replacing keycaps. Let's take a look at the following pictures:
In the above pictures, the top UHK features opaque keycaps and the bottom has backlight friendly keycaps. Please note that these pictures are a bit misleading because in real life the brightness of the opaque keycaps is much dimmer than of the backlit keycaps. It's also worth noting that the final backlighting will be better. We'll optimize the placement of symbols for more even light distribution and carefully choose the best LED. The most important takeaway is that opaque keycaps may suit some, but probably aren't a great choice for most.
In order to make your UHK backlit right away, you can purchase a number of LEDs and solder them to the PCBs. You will have to use 3mm (T-1) LEDs. Be careful to choose a LED type whose rim is not larger than the lens itself, otherwise the LEDs won't fit into the keyswitches. Also make sure to use single color LEDs as bicolor LEDs won't work well. You can pick any LED color but LEDs of the same forward voltage should be used, otherwise ghosting may occur. Fear not, we'll provide detailed instructions for soldering.
Alternatively, you can wait for our backlight upgrade kit that we'll release later. The backlight upgrade kit will contain white LEDs and a backlight friendly keycap set. In the beginning, we'll only provide US ANSI and ISO versions.
As for the release dates, we're really not sure yet. We'll probably release the backlit UHK version and the backlight upgrade kit about a year after delivering the first batch. We're also unsure about the price but it will be reasonable compared to the price of the UHK.
It's worth mentioning that although backlighting is a nice feature, the labels of non-backlit keycaps are easier to see in daylight.
Multiple brightness settings will be provided. One is a global brightness setting of 100 levels that affects every LED including both the LED display and the LEDs beneath the keycaps. The other is a per-key brightness setting of 256 levels which will enable us to do all kinds of fancy animations. This per-LED brightness setting can also be applied to the LED display as a whole. The formula is: actual brightness level = global brightness * per-LED brightness.
We plan to implement RGB backlighting eventually but surely not anytime soon, as it will require a complete redesign of the PCBs.
We also got a question about whether it's possible to solder only a couple of LEDs, for example only the LEDs of the home row. While it is possible, it will likely cause ghosting issues when using different per-key brightness values. This problem can be solved by telling the LED drivers which LEDs are actually present. We can implement a related user interface in Agent to mark individual LEDs populated/unpopulated, but we will only do so if there will be enough interest for this seemingly special use case.
Lastly, I'd like to note that while backlighting is clearly a neat feature, it's not necessarily better than not having backlighting. In broad daylight, the letters of the opaque keycaps are easier to see than the labels of the backlit keycaps. This is also true when the backlighting is off and simply backlit-friendly keycaps are used due to their material.
So this is it! Hopefully, all your questions are answered now. If not, please ask away in the comments. Have a beautiful weekend!