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Harvesting / Teardown of the Pico1 Projector - 450nm, 640nm, + non-DPSS Green

Well I searched corning g-1000 and found some good info.

According to them Its actually a 1060 directly doubled to 530 with a lithium niobate crystal, but this isn't what it looks like to me from the diagram. I'm no dpss expert but, I'm pretty sure a directly doubled 1060->530 shouldn't have a gain crystal. I don't think a combination of a distrubuted-Bragg reflector, an actual laser diode, and a gain crystal counts as a "semiconductor ir laser"

See here:
Green light allows big pictures from small projectors | SPIE Newsroom: SPIE
 





In my hunt for laser knowledge, I came across a type of DPSS know as a disk laser (a.k.a. active mirror).

ActiveMirror.png


I'm still looking into these lasers but from what I've read, they would be perfect for this application. It looks like active mirror may be our culprit.

I'll be sure to keep you guys up to date if i find any more information.
 
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HIMNL9 said:
Just thinking ..... taking away the last turning mirror and powering the projector, before dismantle it, may give you some indications .....

I mean this:

attachment.php


Looking at the mirrors and lenses, the beam paths looks like this, and the turning mirror circled in orange redirect the beams on the image optics ..... so, probably just taking it away without move anything other, will give you the beams coming out from that aperture on the side ..... also if the beams are cycled at high frequency, in the normal working system, turning on the projector and shining the beams on a wall probably will give you an indication about how they are aligned (keeping in mind that the cover acts as heatsink for the electronic, so without the cover the chips are not heatsinked, so, quick tests, or in alternative, can work making a hole in the side where the beams comes out and reassemble the cover)
Click to expand...

As a note, it appears that mirror is actually a cold mirror. 940nm infrared passes right through it. I was thinking about replacing the red diode with an infrared one, but it seems I would have to replace that mirror too.
 
nrp said:
As a note, it appears that mirror is actually a cold mirror. 940nm infrared passes right through it. I was thinking about replacing the red diode with an infrared one, but it seems I would have to replace that mirror too.
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You have me curious now, why would you want an IR diode in there? Where are you finding a 3.8mm 940nm IR diode anyway?

Has anyone else made any progress on getting this green module running solo?
 
Pontiacg5 said:
You have me curious now, why would you want an IR diode in there? Where are you finding a 3.8mm 940nm IR diode anyway?

Has anyone else made any progress on getting this green module running solo?
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I want to do simultaneous structured light scanning and projection. That is, something like this video, but projecting back onto the things being scanned in real time (for slow values of real time). I was planning on having the structured light pattern constantly iterating in infrared while leaving blue and green to do the visible light display.

I haven't found a suitable IR diode yet. I'm not stuck on 940nm, that is just what I had LEDs of to test the mirror with.
 
Doh! I completely forgot about structured light scanning. I'd been playing with laser scanning and wanted to try structured light but I've never had a running projector for more than 10 minutes :D

I'm glad I haven't torn my pico apart yet. I think David just started supporting structured light scanning too. I'll have to figure out how to make this stupid thing play nice with my Ipod.

How are you planning on syncing the camera to the IR output from the projector? Wouldn't the blue and green light interfere with the structured light pattern?
 
Pontiacg5 said:
Doh! I completely forgot about structured light scanning. I'd been playing with laser scanning and wanted to try structured light but I've never had a running projector for more than 10 minutes :D

I'm glad I haven't torn my pico apart yet. I think David just started supporting structured light scanning too. I'll have to figure out how to make this stupid thing play nice with my Ipod.

How are you planning on syncing the camera to the IR output from the projector? Wouldn't the blue and green light interfere with the structured light pattern?
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The PS3 Eye can take in a frame sync signal. I can try to harness the VGA V-sync signal for this, with a microcontroller as an intermediary to get the proper timing.

I have a PS3 Eye modified to remove the IR filter and add an IR bandpass filter.
 
I hadn't thought about that, apparently exposed 35mm film works rather well as an IR bandpass filter.

What are you hoping to accomplish by projecting the green and blue back onto what you are scanning though? I'm not really understanding that part.

It sounds like a pretty sweet project though, you should post a build thread here when you get started!
 
Pontiacg5 said:
I hadn't thought about that, apparently exposed 35mm film works rather well as an IR bandpass filter.

What are you hoping to accomplish by projecting the green and blue back onto what you are scanning though? I'm not really understanding that part.

It sounds like a pretty sweet project though, you should post a build thread here when you get started!
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Film and floppy disc material works decently well, but getting a narrower filter around the wavelength you want works better for rejecting sunlight.

Imagine having a white box on a table with the scanner/projector pointed at it. You can project whatever you want to onto the box, making it look like a house, or a car, or a fishtank. You can then move the box, and because you're tracking live with structured light scanning, you can project the house, car, etc, onto it in the right position and orientation.
 
Ahhh, I see now. You are just using the structured light to track the projection surface. That would actually be pretty cool.
 
I managed to swap the red diode for a 780nm one. It lights up along with the blue and green for a couple of seconds and then it fails some self check condition, the red LED starts blinking, and the projector shuts off. I'm not sure what to do now. The projector is apparently very thorough about making sure it doesn't run when it's not in a normal state.
 
nrp said:
I managed to swap the red diode for a 780nm one. It lights up along with the blue and green for a couple of seconds and then it fails some self check condition, the red LED starts blinking, and the projector shuts off. I'm not sure what to do now. The projector is apparently very thorough about making sure it doesn't run when it's not in a normal state.
Click to expand...

...why would you swap in a nearly invisible infrared wavelength?
 
An update in case anyone is interested in hacking these things. The thing labelled DS1 at the top middle of this image is quite important. It appears to be a set of photodiodes tuned for different wavelengths. The last dichroic mirror is actually a beamsplitter. A small percent of the red and green (and maybe blue?) lasers is directed towards them, and if light isn't detected on startup, the projector powers off. It appears to be ok with the diodes disappearing after startup though.

Edit: There appear to be three leads and three photodiodes, so all three lasers appear to be checked for. I suspect I can do something like short the diode or put the red one in parallel with the blue or green to get around the check.

[
33038d1307210735-harvesting-pico1-teardown-450nm-640nm-strange-green-2011-06-01-21.34.47.jpg
 
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