Live ball spin feedback

[nataddrho]

I am playing around with simple DigiBall displays. This is a short clip of a video where ball spin information is saved live onto video.

Video here

The black line on the white circle represents the tip angle (spin applied to ball, i.e. the tip hit the ball somewhere along the black line). The size of the colored circle represents the amount of spin. 0 RPM is a tiny black circle, 1000 RPM is a large red circle, and is scaled linearly in-between.

Why do you think I missed the 6 ball? Was it an aiming error, or did I move my tip position at the last minute?

Do you think having this graphic is interesting / useful to add to matches / streaming videos?

Thanks

 

[couldnthinkof01]

You looked unsure and put a poor stroke on it. Deceleration?
I think it's cool and could help people learning while watching matches

 

[DaWizard]

Pretty cool!

I did have a slightly difficult time to discern the size of the circle. They kind of all seemed equally sized, just different color. Perhaps a circle with the RPM number is more clear? At some point people will be like "woah he played that with 33rpm!"

By the way, if you know the rpm, the angle and speed (I believe you can with the digi all, right?), is it not possible to deduct the point of contact?

 

[nataddrho]

Pretty cool!

I did have a slightly difficult time to discern the size of the circle. They kind of all seemed equally sized, just different color. Perhaps a circle with the RPM number is more clear? At some point people will be like "woah he played that with 33rpm!"

By the way, if you know the rpm, the angle and speed (I believe you can with the digi all, right?), is it not possible to deduct the point of contact?

Yes, you can. You can either enter distance and then select the impact time on the app, (hands on approach) or...

select the distance and impact time in post processing (play and forget approach).

Here I am using an experimental "DigiBall Studio" program I wrote to select the homographic-corrected distance on the table (red line) and then the travel time from the ball data (cyan line is spin mag data and green line indicates ball impact time). This gives you the exact tip position. Not center of the tip, but where the piece of the tip hits the cue ball.

But as you can see, it is less interesting to a viewer?

Either way, exact tip position requires some extra "distance-time" or "speed" input by somebody or something. If somebody can make a high speed camera setup that perfectly measures cue ball speed, then tip position can be hands free too.

Thoughts?

 

[iusedtoberich]

IMO, you missed because the CB swerved. It was somewhat near the cushion (forcing a high tip position), and you hit it high outside, which causes the swerve to take super quick. Sort of like a purposeful swerve shot when hitting low outside and just slightly jacked up. You have to aim fatter when hitting high outside, in my experience.

 

[kling&allen]

Yes, you can. You can either enter distance and then select the impact time on the app, (hands on approach) or...

select the distance and impact time in post processing (play and forget approach).

Here I am using an experimental "DigiBall Studio" program I wrote to select the homographic-corrected distance on the table (red line) and then the travel time from the ball data (cyan line is spin mag data and green line indicates ball impact time). This gives you the exact tip position. Not center of the tip, but where the piece of the tip hits the cue ball.

But as you can see, it is less interesting to a viewer?

View attachment 724549

Either way, exact tip position requires some extra "distance-time" or "speed" input by somebody or something. If somebody can make a high speed camera setup that perfectly measures cue ball speed, then tip position can be hands free too.

Thoughts?

I think you would be better off using the iconography that people are already familiar with from videos, books, and games (a dot where you struck the cue ball). And then a different indicator for spin magnitude (I agree rpm is cool).

 

[nataddrho]

I think you would be better off using the iconography that people are already familiar with from videos, books, and games (a dot where you struck the cue ball). And then a different indicator for spin magnitude (I agree rpm is cool).

Good idea.

Showing the tip diameter (black circle) as well as the tip contact point (blue circle) makes a big difference.

I can add text for RPM, speed, distance and spin ratio factor (RPM/speed)

I think this is more of what people would want to see.

 

[Pubo]

That's so cool! I also agree that exact contact point is much easier to understand and look nicer. Probably the colored circle with various radius along side with rpm shown next to each other is better. I look forward to it!

 

[kling&allen]

Good idea.

Showing the tip diameter (black circle) as well as the tip contact point (blue circle) makes a big difference.

I can add text for RPM, speed, distance and spin ratio factor (RPM/speed)
View attachment 724594

I think this is more of what people would want to see.

Yes that looks great. I think you could drop the radial line as well?

 

[Patrick Johnson]

0 RPM is a tiny black circle, 1000 RPM is a large red circle, and is scaled linearly in-between.

How do you use that info?

pj
chgo

 

[straightline]

You can plot or at least backward engineer skids?

 

[DaWizard]

And a red center dot in the exact middlso it's easy to see what is the center. Perhaps also do a little bit of inward shading from the edges of the circle to make it look like a sphere.

For RPM you could have a pillar that shows the current, live, rpm? The pillar would change color and size depending on how the rpm changes.
With at the top (static, at the ma point for the shot) a line and number of the max rpm.

For example: I shoot a ball with 351 rpm
The pillar jumps from 0 to 351 and colors orange. During the shot it loses the rotation and you see the pillar getting smaller and it turns yellow and finally green. At the highest point there's a line with 351 above it.

I would think the angle of rotation changes, by the way. At some point the ball is rolling (forward rotation). It would be cool if that radian-line moves along with the angle of rotation.

All this is said without any idea how hard it is to implement

 

[DaWizard]

Im not sure if the speed/rpm ratio is info that is easy to understand. But perhaps it is?

 

[DaWizard]

Here's an image of what I tried to explain:

In this example the cueball was hit with right spin. It's maximum rpm was 351rpm. It's current rpm is 292rpm and the angle of rotation has changed from 3 o clock to half past 1.

It would be cool if that radian changed in length and color, consistent with it's current angle and rpm values.
The grey line shows the original angle and amount of rpm. (it's slightly longer than the red line)

The pillar with the gradient also decreases in size, along with the live values.

Personally I would only show the tip and not the point of contact. Allthough interesting, I don't think it's very valueable information.
Edit: my cue tip is way to small, but you get the picture.

 

[Buckzapper]

Sounds like reverse intake side-vacuum suck on the cue ball, usually applied with a 12mm Elkmaster tip at warp speed. Twirl the cue like an airplane propeller before the shot for maximum applause. Listen to the "wows" from the commentary booth.

 

[Black-Balled]

I hope justdum is watching and sees what it is like to do...something.

Very cool to watch the digi- evolution.

 

[nataddrho]

Here's an image of what I tried to explain:
View attachment 724629

In this example the cueball was hit with right spin. It's maximum rpm was 351rpm. It's current rpm is 292rpm and the angle of rotation has changed from 3 o clock to half past 1.

It would be cool if that radian changed in length and color, consistent with it's current angle and rpm values.
The grey line shows the original angle and amount of rpm. (it's slightly longer than the red line)

The pillar with the gradient also decreases in size, along with the live values.

Personally I would only show the tip and not the point of contact. Allthough interesting, I don't think it's very valueable information.
Edit: my cue tip is way to small, but you get the picture.

Great ideas! I will implement something like this.

RPM magnitude evolution is available already but only over 1 second. RPM vector angle evolution is possible but I haven't calculated that data, and may be reserved for an extended mode. Problem is Bluetooth low energy throughput is extremely small, so the user will have to wait for this data to arrive, possible 10s of seconds.

The tradeoff is that the DigiBall sensor consumes only 1.6mA while running, which gives you 16 hours of play-time before a recharge.

 

[nataddrho]

Here is a video of the DigiBall Studio prototype in action, kind of how I envision that the DigiBall can be used as a "turn it on and forget about it, then look at the data later" method. You need to draw in the distances between balls, which in my head I thought no one would want to do, but after making the program it is a lot easier and faster than I thought. I am liking the results now.

And of course, this is an extended program for people who are interested in self analysis. The product already has a mobile app which allows live interaction at the time of play.

I also want to point out again, that all electronics are in the ball itself. There are no devices that obstruct your playability in any way, which may be unprecedented for a training device.

Thanks for your feedback so far!

 

[BRussell]

Nate one issue that I’m wondering about is the weight/balance of the cue ball. I’m sure the electronics and battery are light weight in there, but how do you compensate for that so that the cue ball gets back up to the weight it should be, and how do you make sure there’s no imbalance?

 

[nataddrho]

I designed the sensor to have the same density as phenolic resin by using various materials.

This question has been the most common.

I should make a video of the ball as a lag shot to show no roll off, and also on an air bearing to show minimal (if any) orientation drift over time as it spins.