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FrozenGate by Avery

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

Well all dichros, and mirrors as well for that matter.. aren't 100% reflective (or transparent) You will get 'waste beams' off pretty much any type of reflective optic unless the other side is painted with something opaque. These photodiodes are just reading those waste beams. However I bet you anything it's not only the 'presence' of light that it's looking for, but intensity as well. It's probably running all three lasers at 100% on startup and making sure all are in spec before letting the DLP pass any photons out of the projector.
 





qumefox said:
Well all dichros, and mirrors as well for that matter.. aren't 100% reflective (or transparent) You will get 'waste beams' off pretty much any type of reflective optic unless the other side is painted with something opaque. These photodiodes are just reading those waste beams. However I bet you anything it's not only the 'presence' of light that it's looking for, but intensity as well. It's probably running all three lasers at 100% on startup and making sure all are in spec before letting the DLP pass any photons out of the projector.
Click to expand...

I think you are right that it is looking for more than just whether the laser is on. It's possible it is additionally timing the laser against the diode response to calibrate the image.
 
This Laser Focus World article gives some information about the green laser.
Another question: Does anyone know what's responsible for the 1:1 short throw characteristics? I'd like to keep the image as small as possible, is there some lens I should remove or add?
 
There is 1 crucial thing I've discovered in my mucking around with the green module.

I've managed to get the green module up and running, and I have a thread about it in the multimedia forum if anyone is interested.

But, the green module contains no form of internal feedback. Instead, it uses the photodiodes (The DS1) to tune itself. If you remove the green laser from this photodiode, it will probably refuse to work properly, as the controller would be rapidly adjusting the crystals temperature trying to find the max power output.

It is also the magic behind the auto magenta adjustment.

Here is the thread where I got ALL the diodes, and the green module running. The diodes are very nice single mode, and have a near perfect beam profile. Just a shame I can't find a source of 3.8mm modules :(

http://laserpointerforums.com/f48/single-mode-445nm-640nm-micro-532nm-68953.html
 
Mine just shipped last night, hope to have it in a week.
Probably won't be tearing it apart for lasers though :P
 
EDIT - Thought #1:

Something just occurred to me. We now know that the alignment is actually accomplished electronically by the MEMS mirror unit. This makes achieving a single combined beam output difficult.

But, how large is the projected square image frame at the exit window of the pico projector itself? If it's relatively small (a few mm), you could simply add a biconvex lens outside the exit window, and focus the entire projected frame down into an infinity focussed beam.

To clarify, this might work here because the projected output is still coherent light (as opposed to with a traditional projector or even a KasEO where it is not).

EDIT - Thought #2:

If someone has a working Pico1, could you LPM the projected output? Presumably the sensor will need to be quite close the exit window to capture the entire frame. Try to project an entirely white image, if possible.
 
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This is an older thread , I know, but I will gladly LPM my SHOWX pico projector.

edit: I got about 26-27mw.
 
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rhd said:
Hmmm, I think you might be wrong about that. I'm fairly certain there is no gain medium being "pumped" in these Corning direct-doubled lasers. I'm pretty certain it's just a 1064 being directly frequency doubled by a KTP crystal.

Maybe it's semantics, but as far as I've read, this process isn't properly called DPSS.

Where are they available for $150? Exciting!
Click to expand...

Yea,quite right, it is not DPSS anymore.It is just a kind of nonlinear transformation technology. But so far as i know, the effeciency of this kind of transformation of diode laser is very poor,how could u be so sure that it is 1064 diode to 532(KTP) but not 808 pumped 532(combination of YVO4 and KTP). The two kind of structure may look the same from the outside. what is more, in my opinion,the operation voltage of 1064 should be low, about 2V or less, how could it work in such a high voltage like 450. So i have my own reason of suspecting it is a kind of green diode.
 
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Hello, rhd.

I sent you private message, but it remains unread. Do you have maybe video adapter for this device?

Btw, did you powered green laser? Working?

Best--
milan
 
Things said:
There is 1 crucial thing I've discovered in my mucking around with the green module.

I've managed to get the green module up and running, and I have a thread about it in the multimedia forum if anyone is interested.

But, the green module contains no form of internal feedback. Instead, it uses the photodiodes (The DS1) to tune itself. If you remove the green laser from this photodiode, it will probably refuse to work properly, as the controller would be rapidly adjusting the crystals temperature trying to find the max power output.

It is also the magic behind the auto magenta adjustment.

Here is the thread where I got ALL the diodes, and the green module running. The diodes are very nice single mode, and have a near perfect beam profile. Just a shame I can't find a source of 3.8mm modules :(

http://laserpointerforums.com/f48/single-mode-445nm-640nm-micro-532nm-68953.html
Click to expand...

Still anyone on this project?
More information about DS1 photodiode?
It is possible to bypass DS1 to replace lasers with more powerful?
Thanks in advance and sorry for my english
 
goldcoast said:
Still anyone on this project?
More information about DS1 photodiode?
It is possible to bypass DS1 to replace lasers with more powerful?
Thanks in advance and sorry for my english
Click to expand...

I agree with goldcoast, any progress on how to bypass the DS1?
 
I've got this same unit and I'm working on reverse engineering the circuitry that drove the green module.
Haven't touched it in a couple of months though.

For anyone interested I got it lasing for a bit and took some wavelength readings.
530.5nm on the green
452nm on the blue
644nm on the red
 
The diode is without doubt 808nm.

Z9OpJDc.jpg


I can't get the system to lase 532, the other two leads may be a TEC. Approximately 4.5V was across them in the system.
 
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Bam.

The laser diode is quite substantial; it would not lase until 300mA. I'm not sure how far it can be pushed...

The second set of leads were a little heater for the titanyl phosphate crystal.

It looks like I'll need to build a photodiode + derivative controller to keep the power steady.

----

Edit: still good at 400mA. I'd rather not break a $200 laser so I'll stop there.

Edit: I broke the heater's bond wires, so may as well pressure test the diode!

Wow, 1A and still lasing!

7SVeiiG.jpg
 
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