Posted On 06/14/2018 By In News

Kailh Sun Switch, Detailed: Centered LEDs And MX Compatibility

Kaihua has accomplished a unique feat: It’s developed a switch that has both a centered LED design and is Cherry MX compatible. The aptly named Sun Switch (PG1511B) was shown off at Computex, and we now have full specs on the latest Kailh switch.

Shine on, You Crazy Diamond

To date, the centered LED designs out there have not had MX-compatible cross stem compatibility, meaning they required special keycaps. Perhaps that’s obvious. The best example is Logitech’s Romer-G switches:

That design makes for focused and centered backlighting, but you sacrifice the ability to use any alternate keycaps. Kailh figured it could do both.

Creating a centered LED situation wasn’t difficult, but they had to find a way to have a cross stem that didn’t block out the light. Looking at the designs, Kaihua took a twofold approach: It used translucent plastic for the stem and made the top half of the switch housing transparent (like an RGB switch).

I’m curious to find out if that translucent plastic will hold up. Plastics can be finicky, and variables like color and transparency can affect strength, durability, and flexibility. In fact, getting that detail right is probably the hardest part of the Sun Switch’s production. We’ll see how Kaihua did in that regard when I get some time with these switches.

It’s important to note, by the way, that the MX compatibility involves only the cross stem; the pin design is different, so be aware of that as you consider any future builds.


Kaihua sent over detailed specifications for the Sun Switch. For now, there’s only a clicky version of the Sun Switch. Kaihua is adept at iterating on its designs, to say the least, so it may well decide to roll out linear and/or tactile versions soon enough–especially if DIY enthusiasts and keyboard OEMs show interest.

The pretravel is fairly standard for a desktop switch at 1.8mm, but the total travel is shaved down a bit to 3.5mm. Shallower total travel seems to be a trend; so many new switches in the last couple of years are between 3-3.5mm instead of the more traditional 4mm.

 Kailh Sun Switch (PG1511B)
Pretravel1.8mm (+/-0.5mm)
Total Travel3.5mm (+/-0.3mm)
Operation Force50gf (+/-10gf)
Tactile Force55gf (+/-10gf)
Bottom-out Force80gf (approx.)
Dimensions15 x 15 x 14.8mm

The Sun Switch isn’t so heavy at 50gf, but it’s perhaps more notable that the tactile force is just 5gf greater. That’s probably going to be awfully light tactility, and indeed, if you look at the force curve, this thing may have a rather linear feel.

The force curve looks to be somewhat inaccurate, given the listed specs. The point of tactility looks like it’s at 1.8mm, but the actuation point is parked at 2mm. What we can infer, though, is that the two happen in extremely close proximity to one another, meaning your click means something. The actuation and reset points look to be the same, too, which means there’s no hysteresis.

The Future’s so Bright…

With the Sun Switch, Kaihua is taking a couple of risks that have high potential upside.

The centered LED design can make a keyboard’s backlighting more controlled and even brighter, and that’s exciting for DIY builders and OEMs alike. However, the Sun Switch has a transparent top half, so you inherently lose some of that control. In other words, you get a centered LED, but not a controlled light pipe. Even so, all underglow from these switches should be nice and balanced.

The other piece that could prove to be a masterstroke or a mishap is the plastic of the MX-compatible cross stem. Being translucent, we suspect that Kaihua had to walk a fine line with the plastic. If the stem holds up under long-term use and feels “right,” the Sun Switch may become a popular one for backlighting freaks and geeks. If not…the sun will set on this switch quickly.

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Seth Colaner

Editor in Chief of Keychatter. Irrepressibly interested in things. Loves devices that click and clack. Data nerd. Proud Midwesterner. Pass the buffalo chicken dip.

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