- Joined
- Aug 14, 2013
- Messages
- 2,640
- Points
- 63
Back in July, I was approached by a member
here with a custom build request. The
requirement was to have a dot, or as close
to a dot as can be reasonably achieved,
floating unsupported in free space for some
type of art installation.
As you might imagine, we quickly discovered
that the main design challenge would be
purely optical. Our journey began as a
search for the right lens or combination of
lenses, and as we were looking into them
and things were becoming clear, we started
seeing that not all lenses are created equal.
This was an early test result using a large
glass LED lens. Some of you may recognize
it from the fail thread. They work well
enough to give an LED good throw, but are
completely worthless for focusing a laser.
After testing a few different lenses with
mixed results, a lens from a 4" magnifying
glass was finally found that could produce
something closer to the desired effect.
Another requirement was that it would need
to be fairly eye-safe in case of any
accidental "viewing events". A 6mm 660nm
5mW module turned out to be perfect. They
are cheap, plentiful, and fairly easy to
use. Plus I had a few just lying around.
Power output was verified to be right
around 5mW.
So with our lens and module in-hand, it was
time to set about putting everything inside
some sort of "host".
After lumbering down to the local lumber
yard, a selection of various pipe pieces
was made. These PVC floor drains turned
out to be perfect once they were cut in
various ways. The 2 that would fit inside
the pipe had their outer flanges cut off.
One also had its inner strainer cut out as
did another one that retained its flange.
The laser module is held in the center of
one "drain" and the lens is pinched between
the other two, making everything a friction
fit and removable for cleaning.
Since these 5mW modules do get a little
warm and they will be surrounded by plastic
inside a closed container with little to no
airflow, it was decided that a heatsink of
some type would become necessary. Sounds
easy, right? Well, this turned out to be
the least enjoyable part of the entire
build and I almost gave up completely at
this point.
After really getting burned by
all_trade_direct on a set of metric drill
bits, which arrived poorly packaged,
chipped, and missing 2 pieces, an initial
attempt had been made to clyindrically
aerate a metallic substance. Seriously, do
not buy from them. They do not respond to
any form of communication. Return shipping
(overseas to UK) is nonrefundable.
Eventually, after some gentle nudging from
the parties involved, who displayed great
patience, it was discovered that a tapered
reamer will produce acceptable results, at
least up to 1/8".
The module is secured with arctic alumina
in such a way that the back half can be
unthreaded to allow replacement in case of
failure. This capability has even been
tested and verified by destroying a
perfectly good laser module that was
working very well and had no reason to
fail, other than to establish a state of
being.
Results
Here is the output floating in a stream of
mist. It could even be shrunk down a
little by using a really large, heavy,
expensive lens or mirror.
Front aperture
DC Connection
Power supply is a slightly modified
Panisonic 200mA phone charger
here with a custom build request. The
requirement was to have a dot, or as close
to a dot as can be reasonably achieved,
floating unsupported in free space for some
type of art installation.
As you might imagine, we quickly discovered
that the main design challenge would be
purely optical. Our journey began as a
search for the right lens or combination of
lenses, and as we were looking into them
and things were becoming clear, we started
seeing that not all lenses are created equal.
This was an early test result using a large
glass LED lens. Some of you may recognize
it from the fail thread. They work well
enough to give an LED good throw, but are
completely worthless for focusing a laser.
After testing a few different lenses with
mixed results, a lens from a 4" magnifying
glass was finally found that could produce
something closer to the desired effect.
Another requirement was that it would need
to be fairly eye-safe in case of any
accidental "viewing events". A 6mm 660nm
5mW module turned out to be perfect. They
are cheap, plentiful, and fairly easy to
use. Plus I had a few just lying around.
Power output was verified to be right
around 5mW.
So with our lens and module in-hand, it was
time to set about putting everything inside
some sort of "host".
After lumbering down to the local lumber
yard, a selection of various pipe pieces
was made. These PVC floor drains turned
out to be perfect once they were cut in
various ways. The 2 that would fit inside
the pipe had their outer flanges cut off.
One also had its inner strainer cut out as
did another one that retained its flange.
The laser module is held in the center of
one "drain" and the lens is pinched between
the other two, making everything a friction
fit and removable for cleaning.
Since these 5mW modules do get a little
warm and they will be surrounded by plastic
inside a closed container with little to no
airflow, it was decided that a heatsink of
some type would become necessary. Sounds
easy, right? Well, this turned out to be
the least enjoyable part of the entire
build and I almost gave up completely at
this point.
After really getting burned by
all_trade_direct on a set of metric drill
bits, which arrived poorly packaged,
chipped, and missing 2 pieces, an initial
attempt had been made to clyindrically
aerate a metallic substance. Seriously, do
not buy from them. They do not respond to
any form of communication. Return shipping
(overseas to UK) is nonrefundable.
Eventually, after some gentle nudging from
the parties involved, who displayed great
patience, it was discovered that a tapered
reamer will produce acceptable results, at
least up to 1/8".
The module is secured with arctic alumina
in such a way that the back half can be
unthreaded to allow replacement in case of
failure. This capability has even been
tested and verified by destroying a
perfectly good laser module that was
working very well and had no reason to
fail, other than to establish a state of
being.
Results
Here is the output floating in a stream of
mist. It could even be shrunk down a
little by using a really large, heavy,
expensive lens or mirror.
Front aperture
DC Connection
Power supply is a slightly modified
Panisonic 200mA phone charger
