Using the Kensington SlimBlade Pro TrackBall with OpenBSD

       762 words, 4 minutes

I remembered my Dad brought home a Logitech TrackBall years ago and I have not bad memories of it. As part of my recent desktop changes, I decided to try a TrackBall. Internet reviews seem to acknowledge the Kensington SlimBlade Pro TrackBall is one of the best devices out there.

So I decided to try it with my OpenBSD laptop.

Spoiler Alter: if that’s just what you’re looking for, it just works© but it sucks.

The device

It is a bit taller than my 6 rows Logitech MX Keys and way bigger than my Logitech M590. That said, it is still one phalange smaller than my whole hand. It doesn’t seem heavier than the M590. It is made of shinny plastic that reflects a lot during photos.

I’m not sure I like this shinning plastic. It really looks cheap to me. I’d rather have aluminium or mate plastic.

It can be connected to the computer using Bluetooth or using a USB dongle.

It has a physical lateral button that switches the pointer speed / resolution. I’m using Level 2 on my 27" monitor.

It is rechargeable using USB-C. The box comes with a USB-C to USB-A cable and an USB-C to USB-A adapter.

What works

I’m using OpenBSD, so no Bluetooth. Not that it matters to me anyway. Plugin in the USB dongle, you get:

bsd: uhidev4 at uhub1 port 7 configuration 1 interface 0 "Kensington SlimBlade Pro(2.4GHz Receiver) Kensington SlimBlade Pro Trackball(2.4GHz Receiver)" rev 2.00/13.33 addr 9
bsd: uhidev4: iclass 3/1
bsd: ums1 at uhidev4: 5 buttons, Z and W dir
bsd: wsmouse4 at ums1 mux 0
bsd: uhidev5 at uhub1 port 7 configuration 1 interface 1 "Kensington SlimBlade Pro(2.4GHz Receiver) Kensington SlimBlade Pro Trackball(2.4GHz Receiver)" rev 2.00/13.33 addr 9
bsd: uhidev5: iclass 3/1, 9 report ids
bsd: ukbd1 at uhidev5 reportid 1: 8 variable keys, 6 key codes

wsconsctl(8) lists the device and limited properties.


Since then, everything seems ok.

The top left button triggers button 2.
The top right button triggers button 4.
The bottom right button triggers button 3.
The bottom right button triggers button 1.

Moving the ball moves the cursor as expected.

Rotating the ball horizontally clockwise triggers button 5.
Rotating the ball horizontally anticlockwise triggers button 4.
Those movements scroll up and down pages in Firefox and xterm(1).

What doesn’t work

The doc says you can click two buttons at a time to achieve alternate actions. On OpenBSD, it doesn’t seem to trigger anything but two individual events. On Windows, you can install the Kensington software and configure 4 extra dual-button clicks. So I guess this is a software-only feature.

I have not found any indicator of battery charging level.


I already admit my biases when it comes to hardware . And those will hit that device really bad.

IT IS REALLY NOISY AND BADLY TUNED. I mean, the clicks are really loud ; louder than my Logitech MX Master 3. And it sounds like plastic echoing in a bathroom ; going “Tic Tac” when buttons are going down and up. You remember those Metal Cricket Clicker toys?

The “wheel” movement emits clicky sound too. It is not that loud. But after a three pages scrolling on my Mastodon timeline, I yelled at the TrackBall to shut up.

The ball is quite nice and precise, when it comes to selecting a window or click a GUI button. It’s a bit harder to select text in a Web page or a terminal. But you may have to get used to it. I’m afraid tiny precise movements for photo editing may be challenging. All in all, moving with the fingertips is a really nice sensation. If you don’t bother the noise, this alone can justify using this device.

The buttons being in different place, the fingers need to get used to it. But it’s quite fast. I still get pasted text when my index forgets that Top Right is button 2 here. Clicking with the thumb gets quite natural. Although I tend to keep it up to not click. Clicking with the pinky is far for easy and needs training.

Now, the worse thing is… I’ve been using this device for less than a day… and I feel pain in my wrist I never had before. In my particular case, it is all but ergonomic! Feels like I’ve kept my hand and forearm with an angle of 45° for weeks. Even the big MX Master 3 doesn’t lead to such an angle. The M590 is even lower.

Last word: I’m getting this item returned.