Advice on RGB projector rebuild

[Datsurb]

SaltyRobot gives good advice.

If you are into the tinkering bit with electronics, you can always reuse one of the flex drivers from one of your unused modules. The diodes can be hooked up in series, and that way only one driver is needed. Just be careful setting the current output of the flex way down before starting. The 520 diodes are fragile.

[HankLloydRight]

Ah ok! So I just assumed that I would use one driver for both diodes, but you're saying you can do either way (single driver with diodes in series, or one driver per diode)? If I get a dual-driver card like what SaltyRobot suggested, why wouldn't I just use both drivers one for each 520 diode?

If I go the 2x 120mw diode route with a PBS cube, where can I get this cube? I see them online for about $60, are they all pretty much the same?

[Datsurb]

My idea was to save you some money. One second hand driver for both diodes in series works fine for me. Downside: If one diode fails, no photons.
Stanwax (member here) have some PBS for the 520nm diodes. The PBS should be coated for the specific wavelength to reduce loss. Its a good idea using a 3d holder for the PBS as well. That way you will be able to much easier finetune your aim for the diodes to make them aligned both in near and farfield.

Espen

[SaltyRobot]

where can I get this cube? I see them online for about $60, are they all pretty much the same?

If you look for "laser beam combine" on ebay you can find ones there are cheaper than $60 more like $25 for the green AR coating. I have one on the way myself to combine a 532 with a 520 for a lumia project I am working on. I have not personally used this cube before but it was recommended to me by Dkumpula who has used lots of different cubes over the years. To somewhat summarize what he told me "the $25 cubes work just fine but make sure that you test them when you get them because sometime they are coated for blue instead of green". I figure for $25 it is worth a shot since I have seen his projectors in action and his combined beams look good to my eye.

[HankLloydRight]

While this is also overkill, what about dropping in something like this:

http://www.ebay.com/itm/520nm-1000mW...-/141952988845

s-l1600.jpg

It fits my case/baseplate layout better and I don't need to worry about getting a separate driver, diode mounts, or a PBS. Or as Datsurb says, I'll have a nice beam box if I need it.

[catalanjo]

@ " http://www.ebay.com/itm/520nm-1000mW...-/141952988845"
Beam size: <3*4mm at aperture .... Beam divergence: <2*0.5 mrad ....without correction makes a nice torch!
Cheers

[HankLloydRight]

yeah, I saw that.

[dkumpula]

A couple things that I haven't seen mentioned yet, Hank:

If you are planning on combining two green diodes to get to 250-300mW total, be sure to go with DTR's 100mW NIchia NDG4216 515nm Laser Diode, not the PLP520-B1 120mW 520nm one. The later is very sensitive in my experience with the most common symptom of having a higher threshold before it lases with a lower max output over time. I've seen significant decreases even with very little use/abuse.

Regarding the cubes, in addition to what SaltyRobot said, those green cubes from FleaBay don't have as good an AR coating on them as compared with the more expensive ones, so be careful of back reflection. (Perhaps a little more distance between diode and cube should be worked in.) In addition they must be hit at almost exactly 90 degrees or you end up with significant losses. In addition, Dave's (LSP) blue cubes work quite well in the 515/520nm range if he doesn't have a green in stock.

Also a hearty +1 for the recommendation of BBE's drivers. I've tried lots of drivers on lower power diodes and BBE's are my favorite with Dave's coming in second. I've been busy replacing all of my Flexmod's with beam suppression for the past year since suffering several expensive/frustrating failures with them. BBE's drivers on the other hand are easy, feature-rich, and reliable. Delivery times vary significantly to the US. I've had two orders take a full month to arrive to the US. (The Russian or US post office is apparently sitting on them, because the post mark is within a day or two after ordering.) Other times, I get them a mere 10 days after the order is placed.

Have fun with your upgrade!

-David