I recall an article in Byte magazine (I think) by Jerry Pournelle (perhaps) back in the mid 1980’s about his adventure when his son lost the IBM mouse ball at the mall. Back then, there was no internet, few electronics stores, and even Computer Shopper was a thin monthly magazine with few aftermarket parts. So he finally got a replacement mouse from IBM, because no one could be found to provide a simple rubber ball of just the right size and weight.
Anyway, I thought of it when my current mouse, a 13 year old Logitech Mx510 optical mouse, lost the ability to wheel down. Back in the ball-mouse days, one had to clean the rollers regularly. But the optical mouse is nearly sealed, and has few moving parts. But Google agreed that the likely problem was dirt. In over a decade, enough dust (crumbs, skin) did filter in through the wheel-side slots to block the sensor.
So here is today’s Object at Hand, the fuzzy internal workings of the scroll wheel.
Light passes through the spokes (when clean) and tells the processor which way and how far it turns. There are several loose parts in this assembly, and it took me a little while to get them back in the right order after I pulled the tiny carpets of fuzz from many tight internal surfaces.
But back together it went.
And back to work.