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Investigating Angular Velocity
mbreitba writes "Sam Barros is at it again, Some may know him for his Railgun research, and some may know him for his homemade cannons. But now he's found a use for all those old CD's you don't need anymore. Personally, I couldn't think of a better use for them."
I have a full copy of that page, with the videos, but no way am I mirroring when the author of the page threatens to sue for $50000 at the bottom.
I bet in the future, you'll be able to get "legacy" CD-ROM drives that just take an optical image of the whole disk once, load the content into a buffer, then eject the disk, in about 5 seconds.
That would be cooler than 12,983x drives.
How about multiple lasers, each reading/writing simultaneously?
My other first post is car post.
if they bounced the laser off a tiny mirror couldn't you use a stationary laser and just spin the mirror? I know nothing about making cd burners but it seems like instead of trying to think outside the box and workaround the physical limitations of spinning a cd they just all decided to make 48x the standard max and give up!
bite my glorious golden ass.
He also notes the disk speed is lowered due to aerodynamic drag.
Personally, I would have been impressed if he had done something to the disk, maybe going over quarters of it with a black felt pen so an optical pickup could have determined its RPM, instead of guessing.
At those speeds, gyroscopic effects can really be exaggerated! Gyroscopic effects alone can result in some really bizarre behaviour when the plane of rotation is changed.
This experiment reminds me the time we got a flywheel spinning off the table-saw motor in high school shop. The flywheel got away from us when unexpected gyro forces wrenched it from our hands. The damage that thing did was talked about from then on to beyond the day I graduated.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
well, the task would then be to retrieve the bounced laser image. it's non trivial to have a sensor at every spot that the laser could bounce on. also, it'd have to dynamically change the focal length on the fly in order to prevent jitter.
P
Humans are slow, innaccurate, and brilliant; computers are fast, acurrate, and dumb; together they are unbeatable
A few years ago, myself and a friend found another, equally interesting use for old CDs:
You can use a stack of them hooked up together as a big high-voltage capacitor!
We connected them all up, then passed in ~20K volts, and it really could hold it's charge (I can't remember the numbers - since then, I've lived in amsterdam for 3 years, and a'dam tends to have a negative effect on ones memory....). What was amazing was when you hooked it up to the powersource, all the disks were attracted to each other and clamped up really tight.
Discharging the thing was amazing, and the 'zap' (for want of a better word) could easily burn through some thick paper...
Maybe when I've got some time I'll repeat the setup, this time with some photos, then I'll enjoy a good ol' fashioned slashdotting...
tom-george.comBecause geeks rate higher t
So just buy another CD burner and burn 2 CDs at once. If you want to go really heavy duty, get a rack of 8 SCSI burners or something. It'd probably still be cheaper and more economical than a spinning laser that has to automatically re-focus every microsecond (or whatever).
why so content on waiting 3 minutes for a cd to burn? do you use a 486 cpu that takes 3 minutes to start your aol too? is it not cost-effective to upgrade to a faster cpu, you would rather have two 486's each take 3 minutes to load 2 aols?
seriously, sometimes you can split the task into parallel tasks and use multiple units to scale horizontally but in the end it still takes 3 minutes to burn a cd! 3 minutes is a long time when your in a hurry. also, if it takes a scsi tower with 32 burners at 48x to burn 1000 cds in a day theres going to be a cutoff where its more cost effective to use one super expensive fast burner.
making a faster burner is not a bad thing, dont argue for the sake or arguing. how would you feel if intel and amd decided 3ghz is the limit deal with it?
bite my glorious golden ass.
ok, since your feeble mind can't seem to come up with a situation where the actual burn speed IS the bottleneck of the entire making-a-cd task.
.iso on my desktop that I want to burn.
I have a
I want to make more than one copy of a cd.. maybe I want to make 100 copies?
I want to just fill a cd with some files off my computer and I dont feel like waiting.
Have you ever tried copying 650 MB worth of data from one hard drive to another? This itself will probably take a few minutes.
we're not all using eide fujitsus
bite my glorious golden ass.
You sir, are an expert troll.
Hmmmmm..... after a minute of thinking. Lasers, among many things can be aimed at very very high speed (ever been to one of those laser light shows?) How about a lens or mirror that spins and a laser that merely utilizes that mirror or lens by aiming at it?
Please people, if youre gonna troll or just make asinine, narrow-minded comments, at least log in so we can list you as "foe".
I heard a story years ago at college of a windmill that was accidentally left running in gale. Apparently the tips of the blades caused a sonic boom!
Dunno if theres any truth in that though.
There are no separate tracks on a cd. It's one long track in a spiral. Raw CD-Rs aren't formatted, so it would be almost impossible to seamlessly combine the work of several write lasers. Plus you'd start to see thermal problems. The process is called "burning a CD" for a reason.
Had one come out and chase me around the lab a bit. An HP VL 400 low profile desktop with a quirk in the CD drive that if you pushed the eject button more than once, it stored the button actions. Pushing it twice quickly resulted in it opening about one centimeter and then closing again. Pushing it three times while the disk was spining full speed caused the tray to open without waiting for spin-down! The disk got air born (only for about half a meter) and skittered across the table after me as I back peddaled away from it in surprise.
The first time it surprised me, the next ten times, I did it on purpose! (Screwed that NT 4 WS disk up pretty well, IIRC).
Any technology distinguishable from magic is insufficiently advanced. - Geek's corollary to Clarke's law
He seems to be using CD-R's. Don't they contain cyanide and/or other nasty chemicals? Doesn't he want to be breathing through some sort of filter if he's going to be shattering them?
Definitely. Why are these guys wearing sunglasses? To look cool probably. The protection effect against high-velocity CD fragments is negligible. Still, it might help against secondary hits, which bounce off walls. The primary shrapnel goes off radially, so you can control it pretty good.
Anyway, these people seem to have too much time on their hands :-)
Dang! Where are all those AOL CDs when I actually WANT them?
Right here.
!#@%*)anks for hanging up the phone, dear.