DigiBall Update and Feature Question

nataddrho

nataddrho

www.digicue.net
Silver Member
Everything is going smoothly. We are in a business phase that requires patience and waiting, but it shouldn't be too much longer. The pass-around earlier this year was a success and a single ball survived travels around the country without any sign of functional problems. A good test for high confidence.

Related topic:
The main purpose of the DigiBall is to provide hands-free highly-accurate feedback on where exactly the tip hit the face of the ball. Since our eyes are usually looking at the object ball, we can normally only deduce from either feel, or how the cue ball reacts off of the table, on where we actually hit the ball. The DigiBall closes the gap on this.

The other half of the problem is, that even though we are mostly looking at the object ball (or most of us are) during our final stroke:
  • How well are we really mentally connected to the object ball contact point / ball fraction?
  • How strongly are we really watching the CB roll down the table to contact the object ball?
  • How good are we at using our eyes to recognize if the CB hit the OB exactly where we intended?
A further application of the DigiBall could be to also use it as an object ball. However the DigiBall has no idea where it is on the table, or have any reference to the shot line, in order to provide accurate cut angle information. I am proposing an additional feature where you would perform the following procedure:
  1. Use the DigiBall as an object ball for your next shot
  2. Before you shoot, use your cue or your finger to roll the ball very slightly towards the center of the cue ball. You can roll it back in place
  3. This tiny rotation generates an axis of rotation that is always perpendicular to your shot line. Call this Ax.
  4. Shoot your shot
  5. The DigiBall will calculate the angular difference between Ax and the impact angle, and will output the cut angle.
I am having trouble justifying this feature. It seems useful for carom. But, since most of you are pool players, wouldn't just being able to see if your OB went into the pocket, or missed thick or thin, be good enough? Do pool players really want to know the exact cut angle of their object ball? Maybe it would be useful for banks or other types of shots that aren't direct? Would touching the object ball to roll it back and forth be completely unacceptable even for practice sessions?

The upside is it is a free feature that doesn't need additional hardware or cost. But I don't want to add too many features on release to cause confusion.

I've been bouncing this idea around in my head and can't decide. What are your thoughts?
 
how would it be usefull for carom?
where you are more concerned with the cue ball angle off the object ball and not vice versa unless i am not understanding.(definitely possible)
 
bbb said:
how would it be usefull for carom?
where you are more concerned with the cue ball angle off the object ball and not vice versa unless i am not understanding.(definitely possible)
Click to expand...
The cue ball angle off of the object ball is directly related to how much object ball you hit. If the object ball is close to the rail you might not have enough time to see the effect angle before it hits a rail, and if you end up missing your shot you may not know exactly what happened unless you are already very good at watching your shot clearly. Some people are still learning how to pay attention better and this feature might help them in this area. Something like that idea.
 
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Interesting idea. I can’t make a recommendation on whether it makes sense to include the feature. I do think exact cut angle would be useful to know.

We obviously know if we over or under cut a ball by where it goes, but it could be useful to learn if you think a shot is more of a cut or less of a cut than it actually is. So I can imagine estimating the cut angle, then taking the shot and — assuming I make it — checking my estimate against the measurement. I found that I tend to over cut certain shots because they’re actually straighter than I imagine, which took me a bit to figure out and correct.

It could also be used to measure throw if you set up a shot at a known angle.

I also have some thought about the implementation:

1. I wonder if people can roll the ball accurately enough. Maybe also orienting the black dot towards the cueball could help.

2. The assumption that the axis of rotation is perpendicular to the shot line seems based on approximation that is only good at long shot distances.

3. Now that I’m thinking about it, why can’t this be done with the digiball as the cueball? The CB direction could be calculated from cue impulse or the direction of friction during travel.

I wonder if there are other possibilities with 2 digiballs!
 
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GorstyBoy said:
if it's tracking 3 axes of acceleration with sufficient sampling rate (likely), the data should be able to show/analyze skids
Click to expand...
Earlier I said:
It could also be used to measure throw if you set up a shot at a known angle.
Click to expand...
But you just made me realize that actually, it should be able to measure throw angle even without a known shot angle, because it should be able to calculate the normal impulse and the tangential (frictional) impulse. This could also calculate the effective coefficient of friction and check for skids by thresholding for particularly high coefficients of friction. It wouldn’t work well for straight shots with topspin where the frictional force is counteracted by the table’s normal force, but that case isn’t too interesting except for the effects on the cueball. Hey, that’d be a use case for two digiballs.

Edit: I think this is wrong b/c the collision duration is way too quick. But how then would the original feature idea work for cut angle?
 
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TheRooster said:
Earlier I said:

But you just made me realize that actually, it should be able to measure throw angle even without a known shot angle, because it should be able to calculate the normal impulse and the tangential (frictional) impulse. This could also calculate the effective coefficient of friction and check for skids by thresholding for particularly high coefficients of friction. It wouldn’t work well for straight shots with topspin where the frictional force is counteracted by the table’s normal force, but that case isn’t too interesting except for the effects on the cueball. Hey, that’d be a use case for two digiballs.
Click to expand...
Oh yeah! The whole set should be digi!
 
I would very much be interested in the object ball to look at spin transfer and throw.

Thinking about looking at the pocket as left, right, center.
 
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