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From: ins_atge@jhunix.HCF.JHU.EDU (Thomas G Edwards)
Newsgroups: sci.electronics
Subject: Re: Kludged Laser Power Supply
Summary: Yeah
Message-ID: <5452@jhunix.HCF.JHU.EDU>
Date: 5 Jun 90 16:51:07 GMT
References: <5395@jhunix.HCF.JHU.EDU> <2667547f-214.1sci.electronics-1@vpnet.chi.il.us>
Reply-To: ins_atge@jhunix.UUCP (Thomas G Edwards)
Organization: The Johns Hopkins University - HCF
Lines: 19

In article <2667547f-214.1sci.electronics-1@vpnet.chi.il.us> cgordon@vpnet.chi.il.us (Gordon Hlavenka) writes:
>No, it works well with an old speaker.  The trick is to glue a mirror onto
>the voice coil, but just a bit off center.  You also want some "slop" in the
>mounting.  I find RTV works very well.  When you play sound into the
>speaker, you get wonderful patterns.

I tried mounting a mirror on a small speaker by taping one side of it
to the rim of the speaker, and letting the rest of the mirror
hang over the coil region.  Very neat effects.  Now all I need is
to replace it with a front surface mirror to allow the best
reflection.

I mounted a mirror on a shaft of a DC motor (mirror is perpendicular to
shaft on the end), and noticed that the reflected laser beam forms
a circle on the wall (I thought it would form a small line...I forgot
that the mirror would be off-axis in two different ways).
I have had fun projecting it onto the wall of a nearby building.

-Tom