Subject: Re: CD auto feeder project - msg#00014

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Re: CD auto feeder project

David Glynn wrote: I don't think I'll have a problem with knowing when the drive opens, or closing it afterwords, nor do I feel knowing where the CD/in/out trays will be too difficult.What I feel is beyond my grasp (sorry for the phun) is th finger on the end of the arm that must retrive the top disk from a large stack of CDs and not drop it as the arm moves from point to point. You could consider using a suction cup with a Lego pneumatics system providing the vacuum. (I vaguely recall a project that made a Lego robot that could climb a sheer pane of glass using this kind of technique. I know Rob Stehlik built it - but every web site I've found that talks about it refers me to a non-existant web page. Well - someone here will know how it was done.) That way, you'd only have to lower your arm down on top of the stack until a touch sensor triggers - then turn on the suction - move it over the CD tray and release the suction. Reverse the operation to deposit the finished CD into the output hopper. This would be a good approach since it would completely avoid the risk of scratching the side of the CD with the data on it. ---------------------------- Steve Baker ------------------------- HomeEmail: <sjbaker1@xxxxxxxxxxx> WorkEmail: <sjbaker@xxxxxxxx> HomePage : http://www.sjbaker.org Projects : http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net http://prettypoly.sf.net -----BEGIN GEEK CODE BLOCK----- GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M- V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++ -----END GEEK CODE BLOCK----- -- Did you check the web site first?: http://www.crynwr.com/lego-robotics

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Re: CD auto feeder project

David Glynn wrote: Steve, I took a ride in the "internet way back machine" (google it) and found this: http://web.archive.org/web/20030605111923/http://www.ecf.utoronto.ca/~stehlik/wwpics.html Aha! Yes - that's the beastie I was thinking of. I always forget about the way-back machine. I didn't know it was possible to create a vacume with the Lego pneumatic parts. Well, re-reading it, it's evident that he's using old pneumatic parts that you can't get anymore. However, his problem was to produce a really strong vacuum - enough to hold the whole weight of an RCX and all those motors to a vertical glass window. To lift something as light as a CD, something much less powerful might work. If you take a large pneumatic cylinder and connect a hose to the bottom fitting (say) then pulling the actuator arm upwards creates a pretty strong suction and pushing the cylinder down again releases it. If you keep the hoses short, that might be enough to lift a CD and hold onto it for a few seconds (that's all you're gonna need to swing it over the drive tray). It looks like the suction cups are not Lego parts though. ---------------------------- Steve Baker ------------------------- HomeEmail: <sjbaker1@xxxxxxxxxxx> WorkEmail: <sjbaker@xxxxxxxx> HomePage : http://www.sjbaker.org Projects : http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net http://prettypoly.sf.net -----BEGIN GEEK CODE BLOCK----- GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M- V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++ -----END GEEK CODE BLOCK----- -- Did you check the web site first?: http://www.crynwr.com/lego-robotics

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Re: CD auto feeder project

David Glynn wrote: I don't think I'll have a problem with knowing when the drive opens, or closing it afterwords, nor do I feel knowing where the CD/in/out trays will be too difficult.What I feel is beyond my grasp (sorry for the phun) is th finger on the end of the arm that must retrive the top disk from a large stack of CDs and not drop it as the arm moves from point to point. You could consider using a suction cup with a Lego pneumatics system providing the vacuum. (I vaguely recall a project that made a Lego robot that could climb a sheer pane of glass using this kind of technique. I know Rob Stehlik built it - but every web site I've found that talks about it refers me to a non-existant web page. Well - someone here will know how it was done.) That way, you'd only have to lower your arm down on top of the stack until a touch sensor triggers - then turn on the suction - move it over the CD tray and release the suction. Reverse the operation to deposit the finished CD into the output hopper. This would be a good approach since it would completely avoid the risk of scratching the side of the CD with the data on it. ---------------------------- Steve Baker ------------------------- HomeEmail: <sjbaker1@xxxxxxxxxxx> WorkEmail: <sjbaker@xxxxxxxx> HomePage : http://www.sjbaker.org Projects : http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net http://prettypoly.sf.net -----BEGIN GEEK CODE BLOCK----- GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M- V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++ -----END GEEK CODE BLOCK----- -- Did you check the web site first?: http://www.crynwr.com/lego-robotics

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Re: CD auto feeder project

David Glynn wrote: Steve, I took a ride in the "internet way back machine" (google it) and found this: http://web.archive.org/web/20030605111923/http://www.ecf.utoronto.ca/~stehlik/wwpics.html Aha! Yes - that's the beastie I was thinking of. I always forget about the way-back machine. I didn't know it was possible to create a vacume with the Lego pneumatic parts. Well, re-reading it, it's evident that he's using old pneumatic parts that you can't get anymore. However, his problem was to produce a really strong vacuum - enough to hold the whole weight of an RCX and all those motors to a vertical glass window. To lift something as light as a CD, something much less powerful might work. If you take a large pneumatic cylinder and connect a hose to the bottom fitting (say) then pulling the actuator arm upwards creates a pretty strong suction and pushing the cylinder down again releases it. If you keep the hoses short, that might be enough to lift a CD and hold onto it for a few seconds (that's all you're gonna need to swing it over the drive tray). It looks like the suction cups are not Lego parts though. ---------------------------- Steve Baker ------------------------- HomeEmail: <sjbaker1@xxxxxxxxxxx> WorkEmail: <sjbaker@xxxxxxxx> HomePage : http://www.sjbaker.org Projects : http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net http://prettypoly.sf.net -----BEGIN GEEK CODE BLOCK----- GCS d-- s:+ a+ C++++$ UL+++$ P--- L++++$ E--- W+++ N o+ K? w--- !O M- V-- PS++ PE- Y-- PGP-- t+ 5 X R+++ tv b++ DI++ D G+ e++ h--(-) r+++ y++++ -----END GEEK CODE BLOCK----- -- Did you check the web site first?: http://www.crynwr.com/lego-robotics