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From: siegman@sierra.STANFORD.EDU (siegman)
Newsgroups: sci.electronics
Subject: Re: Kludged Laser Power Supply
Message-ID: <54@sierra.STANFORD.EDU>
Date: 5 Jun 90 20:26:21 GMT
References: <5395@jhunix.HCF.JHU.EDU> <2667547f-214.1sci.electronics-1@vpnet.chi.il.us> <5452@jhunix.HCF.JHU.EDU>
Sender: siegman@sierra.Stanford.EDU (Anthony E. Siegman)
Organization: Stanford University
Lines: 17

In article <5452@jhunix.HCF.JHU.EDU> ins_atge@jhunix.UUCP (Thomas G Edwards) writes:
>
>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.
>

1.  The mirror should be (MUST be) just slightly OFF perpendicular to
    the shaft.

2.  Bounce the beam off TWO such mirrors in a zigzag "shallow Z"
    configuration.  Include variable-speed controls on both motors,
    and be sure to include a reversing switch for one of them.
    Interesting "circular Lissajou figures" are the result.  Also
    interesting: the difference in patterns when you reverse one