Re: low-tech diffraction pattern

[Dayton Labs <dayton@ERIENET.NET>]

There is an excellent book which describes how to build encoders:

Electric Motors and Mechanical Devices for Hobbyists and Engineers/Bill
Davies
(This guy is very practical - he has a series of like seven similar
volumes on optics,computer interfacing etc. He's a retired professor from
I think Univ of Toronto) If I were to buy one book a year it would be
stuff he writes.

David Gerrick
Dayton Lab - Simulations Group


Herbert H Gottlieb wrote:

> What is a shaft encoder?  How expensive are they.?  Can one
> be easily made by students?  If so, this would be a good
> contribution to the Apparatus section of The Physics Teacher
> magazine.
>
> Herb Gottlieb
>
> On Fri, 17 Sep 1999 09:09:38 -0500 Michael Moloney
> <moloney@NEXTWORK.ROSE-HULMAN.EDU> writes:
> > We do a low-tech version of the diffraction pattern of a single or
> > double slit by using a shaft
> > encoder and phototransistor. The transistor is housed in a black
> > plastic block with an
> > entrance slit on the front. This block is connected to a shaft
> > encoder and a spring.
> >
> >
> > When you slide the block through the diffraction pattern (about 3
> > inches of travel) the shaft
> > encoder turns so in one pass you have light amplitude vs distance
> > (well, angle, which is
> > easy to convert to distance).
> >
> > This is stuff we did ourselves, hardware and software. The interface
> > is a BIB (see my home
> > page for details), so the experiment can be run on a laptop through
> > the printer port.
> >
> > Mike
> >
> >
> > Mike Moloney, Dept of Physics & Applied Optics, Rose-Hulman
> > Institute of Technology
> >
> > (812) 877 8302    http://www.rose-hulman.edu/~moloney