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swehner / foos

Instant replay system for foosball table
GNU General Public License v3.0
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Ball speed tracker - not an issue :) #52

Open bartha-adam opened 7 years ago

bartha-adam commented 7 years ago

Hi guys, this is not an issue, it's more of a brainstorming :) Just wanted to start a conversation on this topic, and did not found any reasonable place on github...

Maybe it would be interesting somehow to measure the ball's speed when enters the goal, and then show it after/during the replay...

What do you guys thing? Any ideas on this topic?

swehner commented 7 years ago

That sounds interesting - having two IR barriers in each goal to measure the time it takes to get from one to the other would be fairly easy, and should work without any major issues. I think we had considered this at some point, but it is a bit tricky to actually attach them physically to the goal - putting them directly on the goal on top of the playing field would have been a lot more difficult on our table.

So in the end we put the sensors under the field on the ball return ramp - before getting there the ball hits the goal's backplate (angled so the ball falls straight down) and then the ramp before rolling by the sensor. To us it seemed that depending on the angle and the speed of the ball some slowed down a lot more than others when getting to the ramp. I'm not sure how different the ball speed is at that point from when it actually entered the goal - so maybe measuring it there might always be pretty slow.

If you could place the sensors on top of the field that would be a lot better I guess, but even if it's not always 100% accurate it would be fun to add it - are you planning on trying out something like that?

bartha-adam commented 7 years ago

I was thinking about the possibility to use computer vision, since in our case, the raspberry camera recording is above the center of the table, directed towards the table. Unfortunately, even at VGA@90FPS, the ball seems to be pretty blurred....

Other approach would be some kind of pressure sensor added to the goal's backplate, so when a fast ball hits the backplate, the pressure sensor would indicate a higher value... Not sure if there is any sensor that could measure force/pressure having an area around 5x30cm....