[Concept] Free-fall test for sensor variance and responsiveness - Overclock.net

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post #1 of 11 Old 08-26-2016, 05:01 AM - Thread Starter
 
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Variance:

Hold a piece of reasonably long (2 meters) drywall, which typically has a paper surface that provides an excellent tracking surface, between the two mice you wish to experiment on, and let it slide free while using Mousetester to record the data.

You need to keep minimal and consistent pressure/angle throughout the fall to ensure the acceleration is only attenuated by a systematic amount. The heavier the drywall the less error is introduced by friction.

Mathematically, it should be a piece of cake to infer the velocity throughout from elapsed time and modified net acceleration. I actually recommend curve-fitting with an acceleration parameter so that you can make multiple trials and normalize them. This will pretty much be equivalent to turntable tests given enough trials.

Responsiveness (slightly uncertain human error margin though):

Same setup, but this time you are free to modulate the velocity via changing pressure or angle. It is always easier to tell phase differences when the motion are modulated.



As an aside, I propose a slight change to the current methodology of responsiveness test: instead of a single swipe, execute a periodic, rectilinear motion, and average the delay at the peaks. Higher frequencies are easier to analyze -- within reasonable bound in terms of speed and distance of course.

It is a truth universally acknowledged, that the comfort of a Logitech shape, is inversely proportional to the R&D put into its making.
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post #2 of 11 Old 08-26-2016, 07:12 AM
 
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So you're proposing that someone else than you does that, right?
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post #3 of 11 Old 08-26-2016, 10:30 AM
 
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Sounds good try it out! I'm not going to be cleaning up drywall off the floor wink.gif
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post #4 of 11 Old 08-26-2016, 12:35 PM - Thread Starter
 
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I will, when I have access to my stuff again.

Thanks for making your friendly assumptions.

It is a truth universally acknowledged, that the comfort of a Logitech shape, is inversely proportional to the R&D put into its making.
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post #5 of 11 Old 08-26-2016, 02:09 PM
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Angle and rotation affect ICS variance. This probably won't be reliable unless you set up enough motion guards that it adds enough friction that the friction itself is a source of variance.

Things like record players slow down in a consistent way. You can probably measure variance with them. And you can move the mouse in/out to measure how rotation affects it. You can keep the mouse in place without adding friction since the mouse doesn't necessarily need to be in contact with the surface.
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post #6 of 11 Old 08-26-2016, 02:26 PM - Thread Starter
 
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Quote:
Originally Posted by wareya View Post

Angle and rotation affect ICS variance.
True, but the variance test require you holding only a single mouse in place throughout multiple trials. It is easily achievable even with your hands if you rest your arm on the table, so it is a moot point

For responsiveness, on the other hand, the human error may be a little more questionable

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This probably won't be reliable unless you set up enough motion guards that it adds enough friction that the friction itself is a source of variance.

Or if the free-fall object is reasonably heavy. As long as you keep the friction constant, the acceleration is determinant.
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Things like record players slow down in a consistent way. You can probably measure variance with them. And you can move the mouse in/out to measure how rotation affects it. You can keep the mouse in place without adding friction since the mouse doesn't necessarily need to be in contact with the surface.

The purpose of this concept is a quick-and-dirty way to do a reasonably good measurement for those who do not have elaborate setups. (To democratize the measurement of "acceleration", if you will)

I have another accessible design that I'm working on that should be simple to set up with readily available equipment, though I won't post them until I managed to get the proof of concept working.

It is a truth universally acknowledged, that the comfort of a Logitech shape, is inversely proportional to the R&D put into its making.
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post #7 of 11 Old 08-26-2016, 10:50 PM
 
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interesting idea but the difficulty is to keep the sensor height constant because even 0.1mm affects sensitivity as much as the actual variance of the sensor.

even with an ostensibly smooth surface it's hard to be certain whether the mouse glides briefly, especially for steep angles, which are necessary to achieve speeds high enough to be of interest to variance measurements

another thing is making sure the mouse doesn't rotate, since if it does it most likely won't be about an axis going through the sensor. probably doable with a wireless mouse but i imagine it would be rather difficult to control for the effect of the cable when the mouse is nearly free falling

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post #8 of 11 Old 08-26-2016, 11:00 PM - Thread Starter
 
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Quote:
Originally Posted by qsxcv View Post

interesting idea but the difficulty is to keep the sensor height constant because even 0.1mm affects sensitivity as much as the actual variance of the sensor.

even with an ostensibly smooth surface it's hard to be certain whether the mouse glides briefly, especially for steep angles, which are necessary to achieve speeds high enough to be of interest to variance measurements

another thing is making sure the mouse doesn't rotate, since if it does it most likely won't be about an axis going through the sensor. probably doable with a wireless mouse but i imagine it would be rather difficult to control for the effect of the cable when the mouse is nearly free falling

Thanks for you input. To clarify, it is not the mouse that is in free fall, but rather the plank, which makes it simpler to hold the mouse against the surface and at constant angle given sufficiently low friction and sufficiently heavy weight.

It is a truth universally acknowledged, that the comfort of a Logitech shape, is inversely proportional to the R&D put into its making.
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post #9 of 11 Old 08-26-2016, 11:14 PM
 
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my bad for not reading more carefully tongue.gif

but i can't really visualize any way to keep the angle consistent

or actually i can't really visualize any reasonable setup for this. is the drywall supposed to be balanced on the mousefeet throughout the fall?

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post #10 of 11 Old 08-26-2016, 11:19 PM - Thread Starter
 
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You are holding a piece of dry wall between two hands (mice), then releasing it, letting it fall down vertically.

It is a truth universally acknowledged, that the comfort of a Logitech shape, is inversely proportional to the R&D put into its making.
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