# measuring ball spin

Discussion in 'Electronic Design' started by bob, Jan 10, 2006.

1. ### bobGuest

Can anyone help me with this conundrum:

I've built a wall that measures how hard a golfball hits it. This
force measurement is converted into a distance measurement, so I can
gauge how far my golfball would have traveled. It is useful to me as a
golfer. However, it would be far more beneficial if I could measure
the ball spin at impact. This would tell me if I have hit a slice,
hook, block, etc.

The ball impacts 3"memory foam. What can be used to measure the ball's
spin? Some type of embedded wire grid? HELP, Thank you, Bob

2. ### Tim WescottGuest

1. Figure out what ball spin does to the foam.
2. Measure it.
3. Compute ball spin.

3. ### cbm5Guest

Figure out what causes spin and measure that. In other words, measure at
the tee. In fact you can do away with the wall if you can measure enough
parameters at the tee. Besides needing something to catch the ball, that is.

4. ### Paul Hovnanian P.E.Guest

Does it have to be a regulation golfball or can you paint (or otherwise
mark) the surface?

5. ### Ross HerbertGuest

Tony Course
http://www.eballgames.com.au/portal/alias__Rainbow/lang__en-US/tabID__1/DesktopDefault.aspx
has invented a device which appears that it might do what you want.
While initially developed as a ball game simulator for Australian
Football, it should be adaptable to other ball sports. Essentially,
the device tracks the ball from impact point and at a certain distance
the ball is stopped by a net. The virtual path of the ball is computed
and a result is posted.

You can see a demo video here
http://www.abc.net.au/newinventors/txt/s1336170.htm

6. ### The Real AndyGuest

Thats what I was thinking. Perhaps a CCD and some tricky math stuff
done on a PC?

7. ### Paul MathewsGuest

Provided that there is a good coefficient of friction between the ball
and the foam, and provided that the foam is not too energy absorptive,
some significant amount of the ball's angular momentum will be
converted to axial acceleration of the foam. If the foam is mounted to
some compliant suspension system, then accelerometers on the substrate
behind the foam will provide signals proportional to spin.
Paul Mathews

8. ### Rich GriseGuest

Make the surface harder, so that the ball rebounds, then take the speed
of the ball and the rebound angle, (and the coefficient of friction)
and you should be able to calculate the spin. You might want to wear
goggles. ;-)

Good Luck!
Rich