An unusual approach

[Daniel Beardsmore]

Friday. Was hoping for more Cigarette Smoking Woman. Got an interesting surprise instead:

Interesting approach.jpg (226.95 KiB) Viewed 2340 times

So, what is this, and what is it from?

I was mooching around bags of old cable pulled out of a site, and one of them had something interesting in it: a Key Tronic Professional Series Mouse, Serial Interface. I swiped the mouse, expecting it to be nothing more than an idle curiosity. Obviously a candidate for the wiki, and as one of the last living stereotypical computer nerds left on the planet, what better way to spend Friday night than pulling apart an old mouse? (What, you didn't think I went out, did you?)

To my suprise, it turned out to be quite a fascinating discovery. Of course, it means that the wiki section on mice needs rethinking, as now our model of mouse history has been overturned.

The OEM is Alps Electric, who became queer bedfellows with Cherry:

key tronic Professional Series Mouse -- Union of Alps and Cherry.jpg (481.6 KiB) Viewed 2340 times

Yep! Cherry microswitches in an Alps mouse. How could that be? I have no idea …

Full internals:

key tronic Professional Series Mouse -- internals.jpg (415.43 KiB) Viewed 2340 times

What's really fascinating is that, as you can see, it is not opto-mechanical! It uses a pair of purely electric Alps rotary encoders:

key tronic Professional Series Mouse -- rotary encoder.jpg (410.43 KiB) Viewed 2340 times

As you can see in the first photo, a pair of contacts feeds current into a central ring, and the current is returned through staggered traces that alternate which input contacts receive current. FCC registration was 1988. Interestingly this is the same year of registration as the [wiki]Apple Desktop Bus Mouse[/wiki], which was opto-mechanical. (I got some better exterior shots of that, too.)

key tronic Professional Series Mouse -- product label.jpg (514.92 KiB) Viewed 2340 times

I tried to get the encoder apart, which appears to be impossible, hence snapping the rotary PCB. I've stuck it back together, but it will never work again:

key tronic Professional Series Mouse -- looks good but won't work.jpg (338.52 KiB) Viewed 2340 times

The shafts that drive the encoders are machined metal instead of the usual plastic, and they run in little plastic bearings:

key tronic Professional Series Mouse -- encoder shaft bearings.jpg (340.79 KiB) Viewed 2340 times

They're soldered into a flexi PCB that wraps around the ball enclosure:

key tronic Professional Series Mouse -- flexi PCB for the encoders.jpg (357.61 KiB) Viewed 2340 times

And yes, some people here will remember when mice had balls:

key tronic Professional Series Mouse -- ball.jpg (323.12 KiB) Viewed 2340 times

The DE9 plug is Key Tronic–branded:

key tronic Professional Series Mouse -- branded DE9 plug.jpg (146.63 KiB) Viewed 2340 times

Even the buttons are high quality: the palm rest and buttons are separate parts; the palm rest is held in with screws, and this in turn supports the buttons:

key tronic Professional Series Mouse -- button and palm rest assembly.jpg (303.58 KiB) Viewed 2340 times

Back in 1988, mice were mice! This is a complete strip down of the mouse — it's a lot of parts:

key tronic Professional Series Mouse -- when mice were mice.jpg (402.47 KiB) Viewed 2340 times

The mouse itself:

key tronic Professional Series Mouse Serial Interface.jpg (255.81 KiB) Viewed 2340 times

It leaves only one question: what do we call such a mouse?

[Daemon Raccoon]

That is quite interesting, I've never seen an electro-mechanical rotary encoder like that before, just hall-effect, optical, and the ones used in multi-meters as a rotary switch.

[dorkvader]

I like how it still uses quadrature just like the opto-mechanical ones.

Internally it seems to be good build quality. Those steel shafts are about the same as the ones in Penny & giles (now US micro products) trackballs.

Now I really want to get a hall effect rotary encoder for my trackball.

[orcinus]

Flexi PCBs instead of cabling, delrin bearing sleeves and mechanical encoders that scrape their traces off after a while don't exactly scream quality to me

[Daniel Beardsmore]

I don't think the traces are worn off the encoder — I think they're just worn smooth and shiny.

The worst mice I've ever used are the old Dell black opto-mechanicals, followed by Microsoft Tracker mice (a cheaper alternative to the Intellimouse). In both cases, the plastic rollers wear (smooth, I guess) and lose grip. Another failure is that the diagonal roller spring loses strength, allowing the ball to contact the inside of its enclosure, which seizes the mouse. The button microswitches tend to lose their strength and reliability over time. The Dell ones could lose grip on the ball within months.

I've not actually connected up this mouse, but it looks like they did a good job with it. I'm not expecting Alps to be silly — what did you expect, ball bearings? It feels solid, nothing appears to be worn with age -- it looks like it should still work as well as it did when it was new.

My PC does actually have a serial port — I'll see if Windows 8 will talk to it.

[Daniel Beardsmore]

OK, yeah, it's worn out with age. The buttons work perfectly. It feels wobbly and extremely hard to push — I'm wondering if the diagonal roller spring has indeed weakened. I don't think I broke anything else …

The horizontal encoder is squeaky but functional; the vertical encoder works, but barely, as I messed it up. Half it should be nonfunctional, as I snapped the rotary PCB.

I'm more impressed that I could just plug it in, scan for hardware changes, and Windows 8 automatically detected that it was a mouse connected to COM1. (And that a 2012 PC even has a COM port at all.)