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!)

These are great to aim at lenses or mirrors for ray tracing, optics
experiments, etc. The only problem is that each device costs $380, which
is total garbage. These low power laser diodes only cost them $10 each
at most, probably less.

Laser Ray Box Item #: 1552737821
https://www.schoolspecialtyonline.ne...CC88941A1 F8B

It occurs to me that I should be able to build a useful device with
cheaper, lower power, pointer lasers. These can be purchased for $5 to
$20 each. But the trick is finding cheap lasers with a useful on/off
switch. All the cheap lasers I see have no real switch. You have to
constantly put your thumb down on the switch to turn it on, and the
moment you let go it turns off. Not convenient. Do you know of any
affordable, small lasers, that can be turned on - and stay on until they
are switched off?

I've never done this before, but I am thinking of picking up cheap laser
diodes, and soldering them together to a battery, or some power source,
but I don't quite know how to do this. Its supposed to be easy, but not
having done this before, I need some sort of instruction. Any idea on
where I might find good instructions, including photos?

Take a look at these cheap laser components: I was thinking of picking
some up here, but I am open to any suggestions!

http://www.wholesaleforeveryone.com/...o de=lasermod

Thanks much for your time,

Robert

Do you know of any affordable, small lasers, that can be turned
on - and stay on until they are switched off?

Robert writes:
Do you know of any affordable, small lasers, that can be turned
on - and stay on until they are switched off?

Make sleeves that slide onto the buttons on pen-type laser pointers
and clamp the button down.

It occurs to me that I should be able to build a useful device with cheaper,
lower power, pointer lasers. These can be purchased for $5 to $20 each. But
the trick is finding cheap lasers with a useful on/off switch. All the cheap
lasers I see have no real switch.

Good idea, but those big paper clips (you know, the ones
with triangle form blue-steel springs) come in the right size to do
it, with
no manufacturing required.

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,

Good idea, but those big paper clips (you know, the ones
with triangle form blue-steel springs) come in the right size to do
it, with
no manufacturing required.