On Thu, 19 Oct 2000 00:14:32 +1300, you wrote:

Some laser pointers come with a set of endcaps which produce effects
like lines, shapes, UFOs etc. I think they use some sort of
holographic/diffraction method. They must be inherently very cheap to
make - don't know if a 90 degree arc is possible though.

>I'm revisiting an old project that I abandoned mainly because of the =
cost
>of one component. Hopefully someone has practical experience of a
>cheaper source for it or can suggest an alternate method. I've looked
>at mirrors (specifically the scanner from a laser printer) but would =
prefer
>to avoid the extra power requirements and moving parts. Audible noise
>and/or vibration are considerations, as well as obtaining the most even
>light spread possible
>
>I need to make an arc of at least 90 degrees with either a red or IR =
laser,
>about 5mW. The lasers are no problem to get at low cost, but the line
>generator lens has so far been tricky. I got a plastic one for $2 which =
is
>about 7mm across with ridges that make a fairly passable line, but
>quite a bit of the light is being scattered you couldn't really call it =
a
>sharp line. For intruder detection or something like that it'd be OK but
>my target is a series of small detectors 10m away. As each detector
>picks up the laser light , the PIC will produce an increasing tone so =
the
>definition of the beam has to be quite good. Some reasonable quality
>optics are needed, and that's when I've found the price goes up. Wrong
>place to comparison shop, but the only reference I have to these is the
>RS catalogue, and both red and IR lasers + LG are around NZ$900. A
>local laser supplier was cheaper but it still would've stung. With a
>perfectly suitable laser pointer available for next-to-nothing surely an
>LG lens shouldn't be THAT expensive
>
>TIA

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