Blinky: The Mouse that Roared

Edit: I still love my Model M. I still get freebies at conferences, but I no longer have small children at home that love to see what I brought them.

Originally posted December 7, 2010 on AIXchange

I’m a stickler when it comes to my computer keyboard. If I’m going to be stationed in any one place for an extended period of time, my keyboard is coming with me.

In the past I’ve waxed poetic about my Model M keyboard. With a PS/2 to USB converter, I’ve been able to continue using the same keyboard for so many years that I’ve lost track.

However, I’m far less passionate about my computer mice. I seem to cycle through different iterations without much fanfare or fuss. I certainly don’t miss the old style mouse with the ball inside; I was perfectly happy to join the ranks of the optical mouse users.

Recently, I got a free optical mouse. Well, it turned out it was only “almost” free, but I’m getting ahead of myself. I picked it up at a conference. Anyone who travels to these technical events knows all about the nice freebies that vendors hand out. Over the years I’ve taken home flying disks, foam footballs, Rubik’s Cubes, flashlights, pens and flash drives, along with plenty of other knickknacks I’ve long since lost or given away.

Anyway, this optical mouse was actually nice. Being just the right size for my tastes, I determined it would make a fine addition to my computer bag. I’m always swapping out the mouse that I take with me when I travel. Lately I’ve divided my time between a corded optical mouse and a wireless optical mouse, but since this freebie mouse came with a nice retractable USB cable, I thought I’d try it on my next trip.

So I plug it in, and I’m pleased. Really, it exceeded expectations. The sensitivity was great, it seemed very responsive and, like I said, the size was just right.

But that blinking.

The mouse blinked, and it wouldn’t stop. It even changed colors as it blinked.

Someone must have thought that a computer mouse that could cycle from blue to red and alternate between solid and blinking was a neat idea–and it was, for about three seconds. Then it became annoying, especially in any room with low light. If there was a simple way to stop the blinking, I couldn’t figure it out. But that blinking had to be stopped.

I figured I could just open up the mouse and … do something. I wasn’t sure what, though. So I asked around. I was told that applying black nail polish to the LED would keep the annoying light from escaping. Someone else told me that a piece of black electrical tape would do the trick.

Finally, someone told me to just get some wire cutters and remove the LED entirely. That seemed more my style.

Opening the mouse was fairly simple, especially since I wasn’t overly concerned with breaking my little freebie. So I went to work with the wire cutters and removed the LED.

It was at this point when I learned something, something I probably should have known beforehand. That little red light that you see on the bottom of your optical mouse? It comes from an LED.

“Able to work on almost any surface, the mouse has a small, red light-emitting diode (LED) that bounces light off that surface onto a complimentary metal-oxide semiconductor (CMOS) sensor. The CMOS sensor sends each image to a digital signal processor (DSP) for analysis. The DSP, operating at 18 MIPS (million instructions per second), is able to detect patterns in the images and see how those patterns have moved since the previous image. Based on the change in patterns over a sequence of images, the DSP determines how far the mouse has moved and sends the corresponding coordinates to the computer. The computer moves the cursor on the screen based on the coordinates received from the mouse. This happens hundreds of times each second, making the cursor appear to move very smoothly.”

Turns out my little freebie had two LEDs: One made all those annoying lights blink; the other performed the critical task of making the optical mouse itself work. In my haste to solve the problem, I’d removed both LEDs. I’d killed my mouse.

Needless to say, I realized my mistake the moment I reassembled it. So I was off to the Radio Shack to drop $1.50 on a new LED that I could solder onto the circuit board. It works fine now, and that’s how I ended up with my free optical mouse that I only paid a little bit for.

I spend my work week expertly configuring, installing and supporting computers that can be worth millions, and yet I can’t be trusted with a device that some vendor paid maybe a couple of bucks to put their logo on. Go figure.