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Full-size Air Hockey Table Robot
07-02-2017, 12:44 AM
Post: #1
Full-size Air Hockey Table Robot
Hi, Thank you for all your help. we're making progress on our full-sized air hockey robot. (pictures attached). If you're interested, some of the mods we've made include:

1. Built an aluminum h-bot
2. Upgraded the motors to Nema 32
3. Replaced the Polulu motor controllers with CNC controllers
4. Mounted everything on a old, used arcade air-hockey table
5. Added a new M12 wide-angle lens to the PS3-Eye camera

It's extremely fast, works very well. Doesn't lose steps, etc.

But we're stuck. Here's our current problem:

Problem: The PS3-based vision system is just very unstable - particularly as we've made the table larger, add the wide angle lens, etc. Small changes in the lighting make it unable to track to puck and robot. So we end up spending most of our time re calibrating HSV values to stabilize it.

Things we've tried: we added a 13% transmission filter (from a telescope eyepiece) to cut some of the light. This helped quite a bit. But Didn't solve our problems.

Any ideas?

1. Is there a better camera than the PS3?
2. Could we focus the camera on only half the table?
3. Would the smartphone camera version be better?
4. We're an Apple family so we don't have any Android phones. do you have an IOS app?

Thanks again!

DCRAW


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07-04-2017, 09:50 AM
Post: #2
RE: Full-size Air Hockey Table Robot
(07-02-2017 12:44 AM)DCRAW Wrote:  Hi, Thank you for all your help. we're making progress on our full-sized air hockey robot. (pictures attached). If you're interested, some of the mods we've made include:

1. Built an aluminum h-bot
2. Upgraded the motors to Nema 32
3. Replaced the Polulu motor controllers with CNC controllers
4. Mounted everything on a old, used arcade air-hockey table
5. Added a new M12 wide-angle lens to the PS3-Eye camera

It's extremely fast, works very well. Doesn't lose steps, etc.

But we're stuck. Here's our current problem:

Problem: The PS3-based vision system is just very unstable - particularly as we've made the table larger, add the wide angle lens, etc. Small changes in the lighting make it unable to track to puck and robot. So we end up spending most of our time re calibrating HSV values to stabilize it.

Things we've tried: we added a 13% transmission filter (from a telescope eyepiece) to cut some of the light. This helped quite a bit. But Didn't solve our problems.

Any ideas?

1. Is there a better camera than the PS3?
2. Could we focus the camera on only half the table?
3. Would the smartphone camera version be better?
4. We're an Apple family so we don't have any Android phones. do you have an IOS app?

Thanks again!

DCRAW

1) The PS3 has been used for this robot as its low distortion and Higher frame rate. There should be some other cameras now capable too. For the Air Hockey Robot EVO we have opted for a regular smartphone with good results (http://www.jjrobots.com/air-hockey-robot-evo/)
2) You will miss information about the location of the puck on the other side of the playing court forcing the robot to response in less time. I do not think it will be able to behave properly. But... it is only matter of trying :-)
3) the smartphones cameras can provide 30 fps top. That is a game limitation in velocity terms but can work (actually, the new version of the AHR can handle those 30 fps). But response speed really matters if you are playing on a larger air hockey table. You can try to reduce the game velocity using a bigger/heavier puck
4) The iOS version will have to wait a little. We are working on something else that is consuming all of our time :-\
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