[sdiy-interim] Laser voltage control

[KA4HJH]

>I need to replace the mirror on the speaker with one that is larger
>so I can fan the display out more.  I'd like to replace the speaker
>with a linear motor of some type so I don't hear it.  Any
>suggestions?  It needs to be physically small and able to be driven by a
>LM386.

You could cut away most of the cone and leave the mirror suspended on a web
of speaker cone. At least that's quieter.

I got a small pair of glavo's with front-surface mirrors fairly cheap
several years ago but I haven't seen any bargains like that since. They're
voice coils just like a speaker but with a mirror pre-attached. I tried
building simple drivers for them from a pair of 386's but I couldn't keep
one of them from oscillating. Never got back to it.

At 4:56 PM -0700 3/28/07, Tim Parkhurst wrote:
>I would think that a low mass is more important that small size
>(although they are often releated). Why don't you try some metalized
>plastic (e.g. silver anti-static bags), or even some aluminum foil for
>a mirror? The metalized plastic sounds like it would be easier to
>handle (less likely to rip or wrinkle) than foil.

A small piece of mirror isn't that massive but it does lower the resonant
frequency and how fast you can slew the whole thing. The advantage is that
it reflects the beam with less dispersion.

If anyone comes up with an *inexpensive* fix for all this that actually
works let me know.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"

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