RGB Scanner Proposal

paulzimm · Dec 9, 2010

Yeah, my little 150 mW trilights mini lab is just awesome in my laser projector. I followed the directions about pot modding it to produce +200 mW of green (along with about 100 mW IR for a total of 300 mW output). I purchased the analog version so I had to set it to TTL mode (on/off only) in my Spaghetti software. Otherwise it makes "dots" instead dimming for certain shows. I am very happy with it...

YouTube - My Laser Projector
* Video was made before I added my red lasers.

ElektroFreak · Dec 9, 2010

goninanbl00d said:
No, that would make absolutely no difference at all.

The problem doesn't lie with the fact that the driver can't modulate properly- it delivers a perfectly proportional current to the diode depending on the modulation input.

The only problem here is, the DPSS process isn't proportional. As a result, you won't get a given amount of green out for a modulation input current.

That's why everyone hates the analog ones- it's more like a stepped curve than a true curve.

Higher quality lasers have a driver with active feedback that compensates for this, and drives the pump diode to acheive a given output, instead of driving the diode at a current proportional to the input.

The TTL lasers don't have this problem- they're simply on or off.

$3 for an IR filter can easily fix that. Why are the most obvious solutions always overlooked?

You're getting $300+ of laser for a little under $150 shipped. Would adding an IR filter be too much to ask?

Non-linearity is a factor in ALL analog greens. These shouldn't be significantly worse than any other.. This isn't the first time that the cheap Chinese drivers have left much to be desired. Paul's comment above means that the driver is NOT actually analog, but more like PWM TTL.

If the problem is simply non-linearity, then no two will behave the same.. some would be awesome, others would be crap which is the case with most Chinese DPSS systems. I've heard nothing but bad reports about the analog performance on these, but all my analog greens are CNI so I'm not speaking from firsthand experience.. the consistency of the lousy reports leads me to believe that it's a driver issue. I've seen uber-cheap greens that perform horribly on their own drivers perform much better on a flexmod. Of course it's never perfect, but there is a good chance that a better driver would have a good deal of impact on performance.

Why pay $3 for an IR filter when the dichros will usually separate it and eliminate it? The only exception being if you have dichros that place the green laser last before the galvos, and even then most times the dichro that reflects the green will pass red. Now that's not a 100% guarantee that there will be zero IR, but in the VAST majority of cases the optical path will remove the IR.

ElektroFreak · Dec 9, 2010

paulzimm said:
Yeah, my little 150 mW trilights mini lab is just awesome in my laser projector. I followed the directions about pot modding it to produce +200 mW of green (along with about 100 mW IR for a total of 300 mW output). I purchased the analog version so I had to set it to TTL mode (on/off only) in my Spaghetti software. Otherwise it makes "dots" instead dimming for certain shows. I am very happy with it...

YouTube - My Laser Projector
* Video was made before I added my red lasers.

Hey Paul.. Which dichros are you using in your projector?

paulzimm · Dec 9, 2010

I am using the dichroic filter kit from CTlasers.com that includes and pair of red/blue dichros and a pair of 3 axis mounts all for $150:

https://www.ctlasers.com/purchases/dichroic-filter-p-54.html

If anyone is interested, I have a set of dichros + mounts from o-like for sale at $25 which includes shipping:
RGB laser systerm combine optical lens /2pcs in a pack [OLRGML] - $25.00 : Welcome to O-Like.com, Your source for laser products
RGB laser systerm lens holder/frame/2pcs in a pack [OLRGBF] - $7.99 : Welcome to O-Like.com, Your source for laser products

goninanbl00d · Dec 10, 2010

ElektroFreak said:
Non-linearity is a factor in ALL analog greens. These shouldn't be significantly worse than any other.. This isn't the first time that the cheap Chinese drivers have left much to be desired. Paul's comment above means that the driver is NOT actually analog, but more like PWM TTL.

If the problem is simply non-linearity, then no two will behave the same.. some would be awesome, others would be crap which is the case with most Chinese DPSS systems. I've heard nothing but bad reports about the analog performance on these, but all my analog greens are CNI so I'm not speaking from firsthand experience.. the consistency of the lousy reports leads me to believe that it's a driver issue. I've seen uber-cheap greens that perform horribly on their own drivers perform much better on a flexmod. Of course it's never perfect, but there is a good chance that a better driver would have a good deal of impact on performance.

Why pay $3 for an IR filter when the dichros will usually separate it and eliminate it? The only exception being if you have dichros that place the green laser last before the galvos, and even then most times the dichro that reflects the green will pass red. Now that's not a 100% guarantee that there will be zero IR, but in the VAST majority of cases the optical path will remove the IR.

Oh, I didn't know it wasn't non-linearity. But AFAIK, the CNI greens do compensate with optical feedback.

If it's more akin to PWM, then that's a different issue altogether.

I have one in the mail, I'd like to see for myself what's the issues with these units. In most cases it'd be used as a labby, not a show unit, so it shouldn't matter.

Also, I was thinking exactly the same thing about the optical path. It'd work, but $3 is worth it for the peace of mind that comes with a guarantee of no IR leakage.

paulzimm · Dec 10, 2010

Please define "PWM"

ElektroFreak · Dec 10, 2010

Pulse width modulation. In the context I'm describing it's a form of TTL where the pulse's duty cycle is changed to simulate dimming of the beam..

goninanbl00d said:
Oh, I didn't know it wasn't non-linearity. But AFAIK, the CNI greens do compensate with optical feedback.

If it's more akin to PWM, then that's a different issue altogether.

I have one in the mail, I'd like to see for myself what's the issues with these units. In most cases it'd be used as a labby, not a show unit, so it shouldn't matter.

Also, I was thinking exactly the same thing about the optical path. It'd work, but $3 is worth it for the peace of mind that comes with a guarantee of no IR leakage.

When there is optical feedback, it's only in higher-end CNIs. The B&W tek/CNI blue lasers that were around here not long ago had it, but the vast majority of CNI heads that we see in the hobbyist/show/portable side of things do not have anything but TEC stabilization.

I'd be interested in seeing the analog response firsthand before I would feel comfortable saying for sure what the issue is.. Let us know how yours does..

goninanbl00d · Dec 10, 2010

ElektroFreak said:
Pulse width modulation. In the context I'm describing it's a form of TTL where the pulse's duty cycle is changed to simulate dimming of the beam..

When there is optical feedback, it's only in higher-end CNIs. The B&W tek/CNI blue lasers that were around here not long ago had it, but the vast majority of CNI heads that we see in the hobbyist/show/portable side of things do not have anything but TEC stabilization.

I'd be interested in seeing the analog response firsthand before I would feel comfortable saying for sure what the issue is.. Let us know how yours does..

In this case, it probably means that instead of dimming the output by reducing the current (like how you're supposed to do so with analog mod), it instead pulses the current to the diode.

That's fine for slow beams, but it'd f$ck up a scan pattern big-time.

@ElektroFreak, results will come in once it gets here.

hakzaw1 · Dec 11, 2010

paulzimm said:
I am using the dichroic filter kit from CTlasers.com that includes and pair of red/blue dichros and a pair of 3 axis mounts all for $150:

https://www.ctlasers.com/purchases/dichroic-filter-p-54.html

If anyone is interested, I have a set of dichros + mounts from o-like for sale at $25 which includes shipping:
RGB laser systerm combine optical lens /2pcs in a pack [OLRGML] - $25.00 : Welcome to O-Like.com, Your source for laser products
RGB laser systerm lens holder/frame/2pcs in a pack [OLRGBF] - $7.99 : Welcome to O-Like.com, Your source for laser products

I wish you had told me that when I was at your place friday- sending a PM now---hak

djpsych · Dec 17, 2010

Thanks for all of the information everyone! Definitely helped me and hope it will help others.

Getting together a list of parts and price shopping around. I will also start a build log, once I start building.

Already bought the following since it has to come from China:
+ C-Media CM106 USB 2.0 External Sound Card Box: http://www.dealextreme.com/details.dx/sku.15746
+ 150MW Green Laser Diode DIY DPSS Module + Power TTL: http://stores.ebay.com/triAngle-lights

The only thing I am a little concerned about is laser safety.
I plan on having the following:
+ Red: 2x 250mW diode extracted from LPC-815 (660nm)
+ Green: 1x 150mW (most likely about 400mW) DPSS w/ TTL (532nm)
+ Blue: 1x 1000mW diode extracted from XJA-140 (445nm)

To protect my eyes from the green and blue lasers I was planning on buying these: RadiantShades for Blue and Green Lasers
However, I cannot find a good pair of glasses for the 660nm range. Does anyone have any recommendations on red laser safety glasses? Or other red, green, and blue laser safety glasses or other combinations?

Also, is it ok to watch the beam shows and projections without safety glasses once it is built because of the disbursement of the laser beams?

paulzimm · Dec 17, 2010

Yes, once the projector is "locked down" on a flat surface it is perfectly safe to watch the lasershow without glasses. If you stop the show and just stare at the full power beam sitting on the wall, it is a bit like staring at the sun (not recommended). By the way, you would see very little of anything if you kept the glasses on while watching the laser show

I use "red" glasses which only block out the blue/green lasers and I really only use them while aligning all the beams together. When doing shows I make sure nobody walks in front of the display and if I have to myself, I make damn sure my back is towards the projector.

djpsych · Jul 20, 2011

Just wanted to let everyone know that I am still in the progress of building my laser projector and that I have all of the parts in hand. Right now I have the green/blue lasers setup and will be working on the red soon. When I finish I will post all of pictures I have documented along the way.

Right now you can see three videos of it in action: sobotadj's Channel - YouTube

paulzimm · Jul 20, 2011

Love the laser shows man, you made that using the included frames in QuickShow2? I just got mine installed a few weeks ago but have not had any time to make a show. Maybe you could send me that AWESOME military ball show you made

Would love to "tinker" with it and see how you made it. There are not too many graphic shows to download on the Pangolin website. Wish I could find more, most of them they have posted are for LivePro

flecom · Jul 20, 2011

looking good so far, gotta get some red in there

djpsych · Jul 22, 2011

paulzimm said:
Maybe you could send me that AWESOME military ball show you made

PM sent!

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