3D Printed stimpmeter
- Thread starter iusedtoberich
- Start date
Why?
constant angle and speed(let the cue ball go)
A number of things would be inconsistent. Off the top of head, i see a few ways that errors would occur using two shafts.
Shafts will have a drop at the tips. Not a perfect transfer to the cloth.
Depending on shaft location on the rail, the angle will change.
You wont be able to line the shafts up 100% the same every time. If one shaft is more forward or backwards or slightly different taper, ramp will not be identical on both sides.
And here is something like that at golf. I think that setup has enough variation to cause problems.
If you are interested in measuring the speed of the cloth, a stimpmeter is a bad way to do it. A much better way to measure the speed of bed cloth is by measuring the time a ball rolls a long way and comes to a stop, like the last length of a lag. The length of the roll and the time go into a simple formula that gives you the equivalent uphill slope of a perfectly smooth ramp that would give the same speed of stopping.
Here's Dr. Dave's page on the subject
billiards.colostate.edu
Here's Dr. Dave's page on the subject
Table Cloth Speed - Dr. Dave Pool Info
Answers to frequently-asked questions about pool table cloth speed.
billiards.colostate.edu
Has anyone other than me tried to attach the read end cue stick to a plate to maintain centerball hit?
Than I use my two predetermined markers to measure my speed using analog or digital comparisons.
You can use the ultrasonic sensors this way it happens in real time. I already did this with the arduino as the brains.
I also filmed it, film analysis is better for table layouts and seeing path lines.
The fun part was making rails to ensure the stroke was repeated it each time. If I didnt live in NYC and understand how train tracks works, this project would never have finished so quickly.
The advantage of having a paper cue was fast proto typing for measuring and designing custom enclosures.
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Than I use my two predetermined markers to measure my speed using analog or digital comparisons.
You can use the ultrasonic sensors this way it happens in real time. I already did this with the arduino as the brains.
I also filmed it, film analysis is better for table layouts and seeing path lines.
The fun part was making rails to ensure the stroke was repeated it each time. If I didnt live in NYC and understand how train tracks works, this project would never have finished so quickly.
The advantage of having a paper cue was fast proto typing for measuring and designing custom enclosures.
This message is sponsored by BARPA, billiards advancement with (non partisan) research projects.
Click my bio for my linkedin, I also do academic work in the Northeast and Atlantic corridor.
I can direct your students for visas in College or GED admissions programs for pathways.
I tried the 3rd version last night. It seems to work! I’ll show some pictures and slow motion when I get organized.
Another way to measure the rail efficiency without a camera is to let the ball roll off the rail to a stop and see how far it rolled. Compare that to the distance the ball rolls on the cloth without hitting a rail. I think it is important for the ball to be rolling smoothly on the cloth when it hits the rail. Also, sometimes the ball slides for a while after the cushion and I think going back up the ramp with that going on complicates things.
You have to angle the ramp slightly for this or lift it out of the way.
40 second video of version 3.
Next steps:
Have to see how repeatable this is.
Items specific to the test instrument:
-Drop the ball multiple times, does it go to the same number? Lift the ramp off the table completely, come back 1 minute later, and replace in the same spot on the rail. Does it repeat to the same number?
-Does it repeat if a different ball is used?
-Does the ball cleanliness affect results?
-Does the ramp cleanliness affect results?
-How sensitive are the results to camera positioning? (parallax)
-How sensitive are the results to the trigger relesesae? How fast I pull away my finger.
If all that seems to be a go, then I could see next steps being:
-Do I want one fixed drop height to simplify the design? Or is it important to have multiple drop heights? What should the height ranges be (we can speak in rough table travel distance). If one height is enough to capture the variation of different tables, why complicate it?
-Some sort of counter wheels or a paper with trial number written on it should be viewable in the picture, and a log spreadsheet/paper on hand when doing testing to record results. A lot of slow motion video gets lost as to what it was testing.
If it all works well after a few more prototypes, I could see it being used to test the following:
-Environmental effects: humidy, temperature.
-Rail bolt location effects: test opposite rail bolt. Test half way in-between rail bolts.
-Rail bolt tightness effects: torque bolts to a low value and test. Torque to a high value and test.
-Table brand effects: test multiple brands.
Have to see how repeatable this is.
Items specific to the test instrument:
-Drop the ball multiple times, does it go to the same number? Lift the ramp off the table completely, come back 1 minute later, and replace in the same spot on the rail. Does it repeat to the same number?
-Does it repeat if a different ball is used?
-Does the ball cleanliness affect results?
-Does the ramp cleanliness affect results?
-How sensitive are the results to camera positioning? (parallax)
-How sensitive are the results to the trigger relesesae? How fast I pull away my finger.
If all that seems to be a go, then I could see next steps being:
-Do I want one fixed drop height to simplify the design? Or is it important to have multiple drop heights? What should the height ranges be (we can speak in rough table travel distance). If one height is enough to capture the variation of different tables, why complicate it?
-Some sort of counter wheels or a paper with trial number written on it should be viewable in the picture, and a log spreadsheet/paper on hand when doing testing to record results. A lot of slow motion video gets lost as to what it was testing.
If it all works well after a few more prototypes, I could see it being used to test the following:
-Environmental effects: humidy, temperature.
-Rail bolt location effects: test opposite rail bolt. Test half way in-between rail bolts.
-Rail bolt tightness effects: torque bolts to a low value and test. Torque to a high value and test.
-Table brand effects: test multiple brands.
Let me know your thoughts after seeing the version 3 video. I can try what you are suggesting here also. As a plus, the way you are suggesting is more intuitive to a player. They can "see" how the bounce/distance went.
could you add a camera holder connected to the stimpmeter without vibrations messing up the video?
Holy smokes, bro. First the fargorate thread, now this.
If the BCA had a rail tester category in their hall of fame, they’d name it after you.
Badpenguin
Well-known member
Wow, looking good. When releasing the ball directly into the rail, is the base of the ball on the table? Or still elevated in the tracks?
What I am going to be interested in is if the tightness (torque) of the rail bolts can be shown to affect the bounce, at least on a diamond.
On a side note, I did some testing of precise banking lines documented by the Poolometry channel (Cross Side (AWS 1.3)). We both have ICA Training Systems, he sent me copies of his precise cross side/corner banking lines, using slow, medium, and fast speeds. Only he is on an 8' Olhausen (I think), I am on a 9' diamond. Banks on my 9' diamond perfectly matched his lines at all 3 speeds. Not EXACT science, but enough to convince me that diamonds don't bank that much different than other tables, they are just more sensitive to speed. Maybe your stimpmeter will help shed some light on all of that.
I think to do the rolling off the rail test you need to:
Set up the height so a ball released on the diagonal (or long way) does not reach a cushion. It would be useful to be able to adjust the height so you get a fixed number of inches of roll on any table you test -- maybe 80 inches.
Set the fixture so it is a known distance from a rail and slightly off straight so the ball won't run back into the fixture.
Measure the distance the ball bounces off the rail. This will be considerably less than the 80 inches. How much less, along with the distance to the rail, tells you the fraction of energy lost in the rail.
I think you just have to measure distances to get the quality of the rail.
So is COR = (distance into rail plus distance rebounded from rail) / (distance traveled when no rail is struck)
No, I think you have to take the no rail case as producing a ball that should roll X inches. Then when the ball goes into the rail, you have to subtract the run to the rail from X (call it Y) and say the ball goes into the rail with enough energy to roll X-Y inches. Then you see how far it actually rolls off the rail which is R. R/(X-Y) will be the fraction of energy retained. Energy is proportional to rolling distance. COR is from a velocity ratio so you have to square or square root the result.
I have found that if you roll the ball along the same line multiple times, the ball starts to roll farther as the cloth gets tamped down, so it's good to move the ramp a little between trials.
My thoughts flashed back to the days of my youth and the Pinewood Derby races. I then thought.....I wonder how long that print takes.
Then of course it was the beginning of this scene......The OG Stimp.