Cheap "analogo" and TTL RGB laser modules off ebay.

In my quest to find cheap rgb modules I stumbled across these modules on ebay. To date I have purchased two. One was a 400mW TTL module and the new one I picked up this weekend is a 400mW "analogo" module.

Attachment 38662

The cases for both of these modules are the same as are the diode and optic mounts. The TTL version only has one fan aimed at the green diode while the analog version has TWO. The optics and diodes are somewhat adjustable, but there is a ton of red glue inside so you're not going to have fun trying this.

The TTL Version has a terrible design flaw where the vent on the side of the laser is right behind the dichros. As a result, quite a bit of green and red light get through. I measured it and it's about 1mW according to my meter.
Attachment 38658
The analog module has this vent atop of the dichros so while you can peer in and see light... no real visible light escapes.


Attachment 38659

When I got these, I wondered if they had an IR filter for the 532nm green. I tested this by placing an ir filter I purchased from ebay in front of the module then checking the new power reading. The output dipped by a very small amount (1-2 mW) so either these do have an IR filter.. or this IR filter I purchased from ebay is just a piece of glass :)



I was also curious about claimed vs real power. Here's an image with my findings of the analog version using an ophir 20-c-a-1-y head. Either this head is out of tune.. or I didn't get all the mW I paid for:
Attachment 38661


Someone requested some beam profile pics so I took a few from 10m. The unit claims to have < 2.5mrad divergence.
Attachment 38660
I'm pretty happy with how well aligned the diodes are on my analog unit. The TTL unit's color alignment is acceptable.. but they noticeably separate even after 2.5m.


I haven't done any linear tests yet nor have I checked out the driving circuit yet.

Thank you for posting this initial review, Macpod!

Its amazing how this hobby has become quite affordable at the lower power end. The ~250mW analog rgb unit would be quite usable in a cheap small projector or lumia box despite having some limitations.

-David

Techhood correct? have had good dealings with the so far. got good PBS and IR filters from them- quick ship too.

How was the modulation on the analog unit? Were you able to get more than 7 colors? AKA is it really an analog driver on that unit. I'm still debating on if I want to get one of these or not. They are so cheap that I probably will even if it only last for a year or so before something burns out.

Same question here: how is the modulation on the analogue version? Would a quick fix with a 10K pot on the input leads do the trick?

I'm currently building a projector for someone at the moment. I'll try my best to assess the modulation later this week or this coming weekend.

any updates on the modulation?

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Originally Posted by macpod

I'm currently building a projector for someone at the moment. I'll try my best to assess the modulation later this week or this coming weekend.

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I can confirm that on mine it is not true modulation but it is not TTL either. It is more like a PWM TTL. I can get different shades of color but when you look at them real close you can see that they are really just segments of each color. It is also nearly impossible to fade the colors in and out. Most of the time you end up with purple, as the green will turn off first. But don't get me wrong I still like what I paid to get this laser. It was perfect for my budget and completed my goal of having a laser projector to play with by the end of the summer. Once I get my Flexmods that should be coming in any day now I am going to remove the driver board the brick laser came with and add flexmods to get true modulation. This laser is not for everyone but I do not feel like I threw my money if the garbage by buying one.

Haven't had time to do testing. I agree with Salty in regards to if I am happy with what I paid for (I'm actually impressed the colors are aligned as well as they are.. I was expecting them to be the same if not worse than the TTL unit).

What do you all propose would be a good modulation test too?


And hey Salty, they never said it was Analog... it's analogo :D

dump the drivers and add new ones. all of a sudden....it modulates!

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Originally Posted by macpod

And hey Salty, they never said it was Analog... it's analogo :D

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That is true. Its like where I have off brand cola just not quite the same as Coke.

I also got one of the 400mW bricks, and experienced the same thing as SaltyRobot. Not TTL and not Analog. I asked the seller and got standard answer from China. Send pictures.
For the price, i will not complain, as the module is very well aligned, probably the 400mw they claim, and the beam fits the mirror of my PT20 quite nice. I`m going to bulid a small RGB as i possibly can with this one, as soon as the my schedule alows me to. My early bench test gave a better result than i hoped for with parts for less than USD 170,-.

Just FYI, I bought one of these 400mW ones off Ebay U.K. on 11-29-2012 and green just died yesterday after maybe 50Hrs usage. Sad.

Does anyone know of a good cheap(ish) driver board for these, preferably one with all three channels on the same pcb?
I bought he 300mW one with "analog" modulation and it looks ok with some tweaking, gives out a stable 380mW!

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Originally Posted by dar303

Does anyone know of a good cheap(ish) driver board for these, preferably one with all three channels on the same pcb?
I bought he 300mW one with "analog" modulation and it looks ok with some tweaking, gives out a stable 380mW!

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I have not found any "analogo" driverboards, but this one is cheap, and will probably do the job. (And yes, its cheap Chinese questionable quality)
USD 16,50 + shipping
(USD 22,- shipping incl to norway)
http://www.o-like.com/index.php?main...2q39fvrtb57782


Datsurb

buy them from dave

I have one of these units in my goldenstar. It's a W600. The red diode lasted about 20 minutes.

Question.... could this unit be taken apart and have a diode replaced? Or are they all epoxy'd together?

This one is also TTL, will not cut it! :)

More like this one but this is a tad too big I think (and overkill!)
http://www.photonlexicon.com/forums/...r-Diode-Driver

I heard it is possible to manually modulate/reduce the intensity for alignment purposes. Which set of pots can be adjusted for this purpose?
Attachment 40366

If one were to replace the driver with a FlexMod Analog driver, how would you go about finding the correct voltage and amperage for these unknown chinese diodes?

Thanks!

don't worry about voltage. just meter the current flow to the diode and set the flex mod for the same current.

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Originally Posted by botman1982

I heard it is possible to manually modulate/reduce the intensity for alignment purposes. Which set of pots can be adjusted for this purpose?
Attachment 40366

If one were to replace the driver with a FlexMod Analog driver, how would you go about finding the correct voltage and amperage for these unknown chinese diodes?

Thanks!

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I'm trying to brainstorm how to go about measuring the current at the diode. On a test load, current is measured at the resistor. But without a test load, is it as simple as measuring across positive and negative leads of the diode? Maybe I'm under thinking this, do I need a test load in place of the diode to measure current?

i just put a meter inline with the diode. this may not be the recommended approach, but it works for me.

Quote:

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Originally Posted by botman1982

I'm trying to brainstorm how to go about measuring the current at the diode. On a test load, current is measured at the resistor. But without a test load, is it as simple as measuring across positive and negative leads of the diode? Maybe I'm under thinking this, do I need a test load in place of the diode to measure current?

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Quote:

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Originally Posted by botman1982

I'm trying to brainstorm how to go about measuring the current at the diode. On a test load, current is measured at the resistor. But without a test load, is it as simple as measuring across positive and negative leads of the diode? Maybe I'm under thinking this, do I need a test load in place of the diode to measure current?

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Current is measured in series, not parallel, so not across but in-line.

Here are some Iphone pictures of the 400mW brick, mounted in a box with 20kppt pt scanners.Attachment 40436Attachment 40437Attachment 40438

Quite pleased myself

Datsub

Quote:

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Originally Posted by botman1982

I'm trying to brainstorm how to go about measuring the current at the diode. On a test load, current is measured at the resistor. But without a test load, is it as simple as measuring across positive and negative leads of the diode? Maybe I'm under thinking this, do I need a test load in place of the diode to measure current?

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Better late than never... I thought I'd answered it anyway, but it was another one. Bit of deja vu for a moment...

Anyway, try a 1R resistor (1% metal film or better) in series with the laser diode. Then measure millivolts across that. As the diode's current is controlled, you will get a millivolt per milliamp reading on a volt meter without upsetting the diode current, or risking ESD by interrupting the circuit. A Lasorb across the diode helps, but so will some small value low ESR ceramic capacitor, as between that and the 1R resistor you'll get a low pass filter that will reduce very short spikes to insignificance wile leaving your fast modulation capability unaffected. Adding that 1R is not required, but in any system intended for experiment, modification, monitoring, it's a good idea to include it. It may not matter which side of the diode you insert it into either, but on a high-side driver you might want to sacrifice its ESD-resisting capability if you're careful and find it more convenient to put it on the ground side. For a handheld meter you would not do this, but you probably should if you want to scope waveforms with the scope and driver sharing a common ground.

Most drivers use a sense resistor that carries full current anyway, and you could read voltage across that, but you'll have to know its resistance and apply Ohm's law to get a current reading. If it's resistance is extremely low, you'll need a very accurate millivoltmeter too. Using 1R in series with the laser diode allows any cheap meter to work well enough.

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Originally Posted by The_Doctor

[snip]Anyway, try a 1R resistor (1% metal film or better) in series with the laser diode. Then measure millivolts across that. As the diode's current is controlled, you will get a millivolt per milliamp reading on a volt meter without upsetting the diode current, or risking ESD by interrupting the circuit. [/snip]

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Lucky no-one listens to me eh? I would never have thought of that.

I do. And you would have, in different circs. You're keen, you'll pick it up faster than most if you stay keen long enough. Electronics are usually cheaper than lasers too (and when I first got into electronics, the closest I could get to a laser was a diagram of a helical flash tube around a ruby rod in a book in the Ipswich library. They didn't even have a photo. How sad is that?! >:) Not knocking Ipswich though. Damn good library..) What got me hooked on the join between electronics and light? Little neon bulbs. I kid you not. I studied whole books on thw weird ideas people came up with for using them. Most forgotten now.

Thanks :)

I used to play with fluorescent tubes and RF but I could never afford to get into lasers, despite the desire. I think I've come into lasers at the right time of life though. I have a little expendable income, have caused enough injuries to myself to avoid burnt retinae and have the sticking power to learn all these complex lasery technicalities.
If it weren't for PL it might be a different story though.

Indeed. For me it was Sam's LaserFAQ that did it. I mean, there were a couple of books at Maplin for 20 quid a time, and plans from 'Information Unlimited' that I was wise enough to pay for only once. And then there was the LaserFAQ, with free access. It's like living in a world where people charge a lot of money for a basic look at something, and then someone opens a gold mine to the public and lets you keep any nuggets you find. No possible contest, is there? :)

Absolutely! Yes, I used Sam's LaserFAQ too. Amazing resource!

So this past weekend I started changing over my Chinese driver board for FlexMods on one of these Brick lasers. So far the Blue and Red are responding nicely and are true analog modulation now. The issue I am having is with the Green. I performed the same process as the Red and Blue. I obtained the current measurement from the Green using a DMM. The current was around 390mA which is approx double the Red and Blue which were around 180mA. I set the FlexMod for 390mA as described in the documentation provided with the drivers. When I modulate the green using LSX I am seeing the green intermittently flicker as it is trying to change shades, Has anyone seen this before? Is this due to the way green laser is produced and is there a way to eliminate it. I do not have this issue with the Red and Blue. I have tried using the Red driver and bumpped up the current, which did not work so I am eliminating a FlexMod hardware issue at this point. I also do not think it is an LSX issue either. Although I do not have a O-scope to watch the signal using my DMM the current appeared linear and did not jump around. The green laser seems to have less flicker when in the dimmer range but when it gets close to fully on it will flicker. I am testing this with a circle pattern and when I say flicker part of the pattern will be full power while part of the pattern will be at a modulated power. Once the modulation hits 5v the full pattern will snap to full color.

I can take video of this issue if it will help. But I am hoping someone has already seen this issue before.

your green is probably a pointer core for poor thermal characteristics and it may just be bad at modulation.

think about replacing it with a 520nm diode..

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Originally Posted by SaltyRobot

So this past weekend I started changing over my Chinese driver board for FlexMods on one of these Brick lasers. So far the Blue and Red are responding nicely and are true analog modulation now. The issue I am having is with the Green. I performed the same process as the Red and Blue. I obtained the current measurement from the Green using a DMM. The current was around 390mA which is approx double the Red and Blue which were around 180mA. I set the FlexMod for 390mA as described in the documentation provided with the drivers. When I modulate the green using LSX I am seeing the green intermittently flicker as it is trying to change shades, Has anyone seen this before? Is this due to the way green laser is produced and is there a way to eliminate it. I do not have this issue with the Red and Blue. I have tried using the Red driver and bumpped up the current, which did not work so I am eliminating a FlexMod hardware issue at this point. I also do not think it is an LSX issue either. Although I do not have a O-scope to watch the signal using my DMM the current appeared linear and did not jump around. The green laser seems to have less flicker when in the dimmer range but when it gets close to fully on it will flicker. I am testing this with a circle pattern and when I say flicker part of the pattern will be full power while part of the pattern will be at a modulated power. Once the modulation hits 5v the full pattern will snap to full color.

I can take video of this issue if it will help. But I am hoping someone has already seen this issue before.

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That makes sense. That is probably why even with the Chinese driver green is pretty much TTL (On or Off) where as the Red and Blue are more chopped (small dashes when heavily modulated). Lots of pink is created when trying to make dim white.

Can you expand on this to teach me a little more. What would make the 520 different? Or what makes a pointer core different from say a laser wave 100mW 532 (just throwing that out there)?

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Originally Posted by swamidog

your green is probably a pointer core for poor thermal characteristics and it may just be bad at modulation.

think about replacing it with a 520nm diode..

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laser pointer cores aren't designed with thermal management in mind. mostly they're just designed to make cheap green when you push the button.

the 520nm diodes are direct injection diodes like your red and blue. there's no frequency doubling, thermal management is much less critical.

you can get raw diodes here:

https://illuminationsupply.com/laser...7#.UpTj92TWePc

or diodes in mounts with lenses here:

https://sites.google.com/site/dtrlpf...nm-laser-diode

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Originally Posted by SaltyRobot

That makes sense. That is probably why even with the Chinese driver green is pretty much TTL (On or Off) where as the Red and Blue are more chopped (small dashes when heavily modulated). Lots of pink is created when trying to make dim white.

Can you expand on this to teach me a little more. What would make the 520 different? Or what makes a pointer core different from say a laser wave 100mW 532 (just throwing that out there)?

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Thanks Swami. Been wanting to buy a 520 diode but the bricks been working. I guess now that I am wanting better quality modulation its time to pull the trigger on the 520. Surgery on the brick is going to be fun. (roll eyes) Hell I'm not even sure if surgery on the brick is going to work. LOL

i have been playing with a little build of single mode red/green/blue laser diodes... you will be blown away.

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Originally Posted by SaltyRobot

Thanks Swami. Been wanting to buy a 520 diode but the bricks been working. I guess now that I am wanting better quality modulation its time to pull the trigger on the 520. Surgery on the brick is going to be fun. (roll eyes) Hell I'm not even sure if surgery on the brick is going to work. LOL

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Blown away by how much it cost to make one from scratch? LOL This hobby is a money pit after all.

Yeah for home use I am thinking single mode diode projector is the way to go. Are you finding you need PBS cubes and anamorphic prisms and such to get great results or are you able to just use G2 lens and dichroic lens?

I think this is going to be next spring/summers project for me.

you don't need cubes and prisms.

Attachment 41019

Quote:

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Originally Posted by SaltyRobot

Blown away by how much it cost to make one from scratch? LOL This hobby is a money pit after all.

Yeah for home use I am thinking single mode diode projector is the way to go. Are you finding you need PBS cubes and anamorphic prisms and such to get great results or are you able to just use G2 lens and dichroic lens?

I think this is going to be next spring/summers project for me.

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Very nice. I likey

Thanks for the info

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Originally Posted by swamidog

you don't need cubes and prisms.

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What lenses are you using for each colour? I used to assume that the same might work for all with a broadband coating, but there's so many to choose from now. Did you end up with a choice based on lots of trial and error?

Edit:
Never mind, I saw the DTR link in an earlier post now. Acrylic? I used to use them. Now, I want glass only, the lack of temperature shift to focus is total luxury. :)