Hi all, While disassembling a junk CD drive the other day, it occured to me that inside here is a very precise linear positioning system. if one were to combine 2 of them you could have a small range but very precise X-Y positioning stage, maybe useful for some really cool stuff, or just for the heck of it. Looking at the one I have, there is a rack and pinion setup the moves the head back and forth, driven by a small DC motor through some anti-backlash plastic gears. The motor dirves a gear that has a ring of magnetic material attached around its periphary, that hangs over a tiny PCB with two small 4 pin SMT devices the are just below the magnet ring. I am guessing that these are some sort of hall efffect sensors that are used for position feedback to control the motor, and thus the linear position. For even finer control, one could actuate the voice coils that move the optical head back and forth and up and down.
I would like to be able to "manually" position (with a pot or whatever) the head via the motor that drives the rack and pinion, and then tweak it with the voice coils. In a few (very) limited experiments I am able to move the head via the voice coils by applying voltage to the appropriate points.
Now I am not near smart enough to be the first one to have thought of this. Anyone know of anybody doing this already? I would like to play with such a system, but don't really want to "re-invent the wheel". If anyone has seen anyrhing like this, please point me in the right direction. A google search has not turned up much, but I may not be picking my search terms well, either. Could you do this in software using the existing hardware? I am not a s/w guy, so I would appreciate some opinions as to wether that is a stupid approach or not. Anyone know of a place where one could find schematics for one of these things? Any ideas or comments?
Thanks for any advice!
AL A.