Why are mouse sensors in the middle of the mouse?

April 7, 2008 5:28 PM

Why are mouse sensors in the middle of the mouse (and not at the front)?

In 1987 when Microsoft was having the Microsoft Mouse developed, mice generally had their balls at the back of the mouse, as it was cheaper to build it that way.

Prototyping and cursor precision testing showed that control increased dramatically when the ball was placed as far forward as possible -- because the fingers could make micro movements vs. the wrist and forearm making macro movements.

But now all the mice that I can find have, at best, their sensors in the middle of the base. It seems that it should be simpler (cheaper) to put laser sensors at the front than it was for balls because these are thin, solid state components.

Do you know why they seem to have reverted? Is it purely a cost thing (there are some pretty expensive mice)? Has there been new research done? Do any mice have their sensor way up front to let the fingers do the pixel pushing?

posted by yt to technology (15 comments total)

Not all optical mice do have the sensors in the centers. My Wireless Mighty Mouse has it located front and center.
posted by DoctorFedora at 5:30 PM on April 7, 2008

Just a guess: To save money and effort, manufacturers of optical mice are using many of the same parts they used in their old ball mice, and the laser goes where the ball used to be because it fits there.
posted by Faint of Butt at 5:34 PM on April 7, 2008

I believe it's cost and ease of manufacturing. The buttons are in the front (often many buttons, wheels, etc.) -- jamming the sensor in there as well would probably require smaller, more expensive components.
posted by Krrrlson at 5:35 PM on April 7, 2008

My Microsoft/Razer Habu mouse actually has it 2/3 of the way back towards the wrist. If it weren't for the 2000dpi sensor, I'd be more annoyed, as precise movement is important to me.

So my theory is that more precise sensors have made up for the effect of moving the sensors back.
posted by qvtqht at 5:39 PM on April 7, 2008

Those studies applied to ball mice which had a much more limited resolution. Most optical mice have enough resolution that there is little to be gained by having it mounted farther forward. Having the sensor up front does not affect up/down movements, only side to side rotational movements.

The main reason is that the cable, button switches and scroll wheel are up front. This doesn't leave a lot of room on the circuit board for the LED or laser.
posted by JackFlash at 5:46 PM on April 7, 2008

In fact, I think the scrollwheel on my Microsoft mouse takes up the whole vertical height, so it's right where the theoretical ideal location of the sensor would go.
posted by smackfu at 6:16 PM on April 7, 2008

yt: Prototyping and cursor precision testing showed that control increased dramatically when the ball was placed as far forward as possible -- because the fingers could make micro movements vs. the wrist and forearm making macro movements.

I don't know how the average person uses a mouse, but I use my finger tips even though the sensor is in the middle. And for me, mouse movements are a combination of finger motion (for precision work), and wrist/forearm motion. Playing around a bit, I have trouble believing that moving the sensor would make any difference at all to my use of the device.

My suggestion.. The study was conducted in an age where people didn't know how to use a mouse properly.

qvtqht: So my theory is that more precise sensors have made up for the effect of moving the sensors back.

That could only work if they did some kind of geometric transformation that projected sensor measurements to motion of the front edge of the mouse.. They don't do that, verify this yourself by rotating your mouse about several different axes.
posted by Chuckles at 7:41 PM on April 7, 2008

It doesn't really make any difference where the sensor is located. And the front is full of switch and roller mechanisms. There's more room in the middle, so it's mechanically easier to put it there.
posted by Class Goat at 7:42 PM on April 7, 2008

I agree completely with yt; having the sensor lie directly under the tip of the index finger would increase the dexterity of mice.

Ever try signing your name (quickly, esp.) with a mouse?

Because of the shape of most mice, there's not a lot of real estate for the sensor.

Besides, most mouse users are now used to having the sensor/ball being under their knuckles and would probably balk (initially) at an improved mouse.

My Logitech MX laser has the sensor right where I'd catch a baseball with a baseball glove (if I caught right handed) but I'd much rather have it 3cm or so forward.
posted by porpoise at 8:31 PM on April 7, 2008

Porpoise, few users expect to use mouses that way. Most who need that kind of control get a tablet.
posted by Class Goat at 9:00 PM on April 7, 2008

Mon dieu, I really want one of these mice now -- it sounds like a fantastic idea.

I'm going to agree with everyone here that practical and mainly economic reasons dictate this. The thing is, though, the sensors themselves can't be terribly huge -- it's just a laser diode. In fact, the bulk of it doesn't even have to be directly above where it senses if you use the right parts. I guess the "right parts" in this case are cost-limiting.
posted by spiderskull at 9:59 PM on April 7, 2008

Sounds like there's a niche here for a luxury mouse with two optical sensors, an onboard processor that combines positioning information from both, and a carefully gridded setup sheet that lets the user pick the exact location of the active tracking spot (this could even be outside the mouse's envelope, if desired).

Having this kind of sensor redundancy would presumably also go some way toward getting rid of the annoying "instant zoom to top left corner" effect you occasionally get when using an optical mouse on a surface with half-toned pattern.
posted by flabdablet at 1:28 AM on April 8, 2008

One useful side-effect (unintentional perhaps) of having the sensor closer to the middle of the mouse is that the mouse can be used closer to the top of a mat, leaving more room for the wrist to rest on the mat. I've noticed that I tend to use the mouse almost entirely in the top half of the mat; if I occasionally push the mouse beyond the edge of the mat it doesn't matter - the sensor is still over the mat.

Also, it's probably worth considering that the position of the hand when using a mouse is different from the position used to hold a pen; that people often take a long time to learn to use a mouse implies that the action doesn't have much in common with writing, so having the sensor close to the fingertips may not hold any great advantage.
posted by le morte de bea arthur at 2:12 AM on April 8, 2008

Like most people, I move the mouse by gripping the sides. I don't know anyone who actually uses the index and ring fingers to move.
posted by mphuie at 3:25 AM on April 8, 2008

If you pretend like the sensor is underneath your finger tip, and write a name that way, how does it make any difference where the sensor actually is?

I assume it's so rotation of the mouse itself doesn't pose quite such a problem (having it pivot rather than be at the centre point always). I too hold a mouse by the sides, so the centre is where I'm holding it, and also I'd put money on it being where the space is.
posted by opsin at 3:41 AM on April 8, 2008