[Laser] cheap laser pointing hardware

[KY1K]

Hi Everyone,

I might have stumbled on something worth making note of, so I thought I'd 
run it by the list.

Last night, I took apart an old 4 GB single platter hard drive that died 
years ago. Besides finding a nice magnet, I also realized that the drive 
could potentially be the answer to some laser pointing problems.

After the platter is removed, the guts mechanical guts of the drive are 
exposed. The mechanism that moves the head assembly across the face of the 
platter to access various tracks is nothing but a fixed magnet and a coil. 
The coil is energized to push against the magnetic field of the magnet. 
Obviously, the quality of the mechanics in this area have to be good, or 
else the drive would be less than consistent.

  It looks to me like a small laser could be mounted on the arm and 
controlled in a single axis by a small variable constant current source 
connected to the coil windings, providing about (estimated) 20 degrees of 
movement.

I've never heard of anyone using these to aim lasers, so I hope this isn't 
old news.

Keep dem lasers lit.

A