swami makes some 445
normally i won't post things until i'm a little more along in the process, but i'm on my way out of town (dinosaur bone hunting in utah) so i thought i'd share now. be warned, this is nothing more than a rough and ugly proof of concept.
i'm still giddy about these 445's.
maybe we all are. little blue suns in a can.
i'm starting work on a galvo based projector... my love of lumia runs deep, but i have a plan. no, i'm not telling you. not yet, at least. well, you could buy me a latte and i'd probably talk.
since i'm building an rgb system, it'd be ideal if i could make a reasonable 445 beam. something more of a spot, than a line. something to match the other colors. i bought a handful of anamorphic prisms a while back. they're great, but they only go so far. it's still a line. sure, it's a stubby line, but it's still a line.
given how cheap and powerful the diodes are, i wasn't concerned about being efficient. i just wanted reasonable beam specs and enough power for color balancing. my target was about a watt. it's easier to turn things down than up.
i thought things through for a while.. how do i reduce divergence on one axis and increase it on the other? i drank a lot of coffee. i realized i was being dumb.
you don't need to increase SA divergence. you just use another diode rotated at 90 degrees. i grabbed a spinal tap napkin and did some sketching. you'll immediately see why i'm not allowed to draw.
once i had some chicken scratches down, i turned on "king of the hill" and did some modeling.
if it's not clear, the idea was to use two 445 diodes through a pbs cube with each diode being prism corrected before the cube. i rendered sk12 mounts for the diodes, but switched to dave's mounts because i didn't have L-brackets and needed to mount the mm1's close to the base.
sugeek gave me a beat up chunk of Al plate a while back. it was worthy for a proof of concept test.
i countersunk bolts through the bottom of the Al plate, then used large nuts as spacers and threaded the mm1's onto the bolts. this actually worked very well. once everything was roughed out, i epoxied mirrors to the mm1's and put things together.
while i was waiting for the epoxy to cure, i annoyed a banded gecko that was eating crickets in my garage.
once i got everything aligned, i took a couple pictures and did some measurements. my poor phone camera is really no good at lasers. the spot is considerably smaller and sharper.
the beam exiting the pbs cube is about 4mm square and the beam scorching my paint from 40' away is about 12mm x 12mm. from 5' away, you can *just* make out the "+" shape. from 10' away it looks nice and round. i'm getting 900+ mW out and it's not even breaking a sweat. i'm sure i could crank it considerably higher, but i have no need to. i'll probably end up turning it down for color balance.
Last edited by swamidog; 05-25-2011 at 18:09.
suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.