TPU Clue:
I happen to be working on a device for another project that has a disk that can both rotate on its Z axis and vibrate ( stroke ) on its Z axis. Both of these cycles are variable.
So.... I decided to do a little of my own after hours testing on the washboard effect.
With the device spinning on a calibrated surface, pushing the base of the device in one direction with the end of a digital force gauge, I could not get any washboard effect.
Picking the device up and tilting produced gyroscopic effect.
With the device vibrating on a calibrated surface, pushing the base of the device in one direction with the end of a digital force gauge, I could get noticeable washboard effect.
Picking the device up and tilting produced gyroscopic effect.
My theory is the motion in the TPU is in the Z axis.
Quote from: darkspeed on 2010.01.09, 22:13:28
My theory is the motion in the TPU is in the Z axis.
"motion" of what?
Well that is the question..
In the video when he sets the TPU down edgewise it has a very small contact patch with the large free surface area of the glass and there is a very distinct screetch around 6khz.
If the motion was in the Z axis at 6khz then it would resonate aginst the glass as it made contact turning the table top into a speaker. I think it did.
The distance traveled in the Z axis at 6khz would be hard to perceive but take a ring of a few turns of bailing wire, hot glue it to a speaker cone near the outer surround, feed it a 6khz signal and you will feel a slight vibration, gyroscopic resistance, and if lucky a little washboard across a calibrated surface.
I would assume three coils with two " near " the same frequency and one out of phase " at any given moment " will give you this motion in the Z