Re: How to make laser ray device for optics demo?


"Robert" <robert@xxxxxxxxxxxxxxxx> wrote in message
news:g2ejj.7413$sA6.2863@xxxxxxxxxxx
Next month I am going to be teaching a class about optics, and I'd like to
use a set of lasers to show them how rays diverge and converge in various
situations. Students will literally be able to see things like this:
http://www.colorado.edu/physics/phys...1/topic23.html

Frey Scientific sells what looks to be a wonderful device: It has 5
side-by-side, 1 mW diode lasers, all lined up next to each other. It makes
five parallel lines that do not diverge (at least not to a significant
degree over the length of a lab table!)

Hi Robert,
I've seen the cheap laser pointers for $1.00 at two different places, also
seen then the same laser at $10.99.
It comes with 5 changable tips to display some form,
3 batteries and key chain.
I used a proper size dowel, mounted an electrical contact on the end with
a wire trough the center of the dowel. I drilled a hole in the battery cover
to let the wire out. The tube is the other electrode , I just used a thin
piece of brass shim stock wedged between the tube and the battery cover with
a wire soldered to it.
As another solution for the second electrode you could put some type of
contact on the side of the dowel but it would need to be springy to keep in
contact with the inside of the tube.
Note, the battey cover is easily breakable plastic and the inside of the
tube has a thin clear plastic tube used to insulate the battery cases from
the tube housing.
I would use a strong tape to permanantly close the switch. Then wire the
lasers in parallel and supply 4 to 4.5 volts from power supply.
Mike


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