New DX Green MODULES

[RA_pierce]

I see. My second thought was that your setup is not delivering sufficient amperage or voltage to the diode. The stock driver likely consumes a volt or so itself. Perhaps increasing the voltage a bit could fix it... but I wouldn't try it without diagnosing the problem properly first. Let us know how it works out.

These 200mW modules seem like they give a decent output power for the price, but they seem pretty sensitive.

 

[MarioMaster]

Yup. Definitely 5.6 mm for the 30 mW and 20 mW DX modules. Double-checked all three modules. all three are the same exact open-can IR diode. Retaining screw? What brand of module do you have and what's its power?

If you refer to the first pic of my photo album, the first part of the module (with the diode and crystal) is one solid piece of brass with the diode directly pressed in, and the crystal is glued to a 3/4 brass slug, glued directly on top with clear epoxy. At the back of the module, you can easily see the three notches of the back of the diode (can't see them in the last pic but trust me, i've seen them) and the cavity is precisely 5.6mm. The front hole though is closer to 3 mm, barely enough space to distinguish the familiar outlines of an open can. Looks quite like the red diodes found in GGWH20 sleds.

But i would not be surprised that the higher power modules have a 9 mm high power diode in them... (1W - 2W?) i am particularly intrigued by Seoguy's picture of two modules side to side, there seems to be a distinct difference between these two modules (the brass slug and the actual size of the crystal).

Robert

Robert

Mine was the 200mW module from DX, same as everyone else bought. There is a little ring screw that held the diode in place. I sent it back to DX so I can't take any new pics of it.

 

[fotonphorces]

I see. My second thought was that your setup is not delivering sufficient amperage or voltage to the diode. The stock driver likely consumes a volt or so itself. Perhaps increasing the voltage a bit could fix it... but I wouldn't try it without diagnosing the problem properly first. Let us know how it works out.

These 200mW modules seem like they give a decent output power for the price, but they seem pretty sensitive.

Maybe. However since it did work the first time it should work any other time with that setup. There might be a good chance that that driver is giving less voltage or amperage.

To test this, I need to make my own. How much voltage and current would you guys recommend to give to this diode?

 

[seoguy]

@ReNNo:

Thanks for all the pics and good tech info! :gj:

It's 5.6mm diode inside.

Good to know! Based on an analysis of price, $/mw, and % change between the different models, I had figured that the breaking-point between the high-power (9mm) and lower-power (5.6mm) models was likely between 50 and 100mw, but we needed to see a 50mw unit to be sure.

Your information just confirmed that, thanks!

Current through diode is 277mA and forward voltage is 1,78V.

What is the current to the driver? I understand your way of measuring is more accurate - the reason I ask is to be able to compare yours with others, as that is how everybody else has reported their's.

Tested it with 2xaaa (3V).
I also tried 2xaaa NI-MH Rechargeable batteries (2.5V) and current was almost the same.

Based on the driver design, I knew it could operate at under 3V, but did not know how low it could go.

That is VERY useful information - as I have been buying a LOT of alkaline AAA's lately!

Although with pot modding, the lower-power modules are drawing almost 3/4's of the max current that brand-new alkaline AAA's can provide. Does anybody know the max current capabilities of NiMH AAA's?

Module starts with very good brightness first second, but after brightness goes down.
And after about 1 minute of warming up, it looks a bit better.

My eBay <10mw does the exact same thing. It could be just the module stabilizing.

I'm not really satisfied with this module...

It can't burn black tape (50mW DX True can).

I believe the DX True's (at least the low-power ones) are using the same module!

Try this...

Pot-mod slightly so that current to the driver is 299ma - that is the same setting that was measured by Bob_Boyce as the factory setting on a real DX True 50 (so it should be safe).

Be very careful, as that pot is extremely sensitive. (They use the same driver on the high-power models, so the pot has a wide range - my high-power module is drawing 530ma - and the pot is not even turned up halfway!)

Depending on the quality of the module, crystals, & crystal alignment, that should be able to get you up to as much as 77mw of green!

You might be able to take it a little farther than that on current, but don't push it too far! Also, if you see the brightness start to drop, then back-off - that likely means that you are overpowering the diode, causing it to overheat, causing it's wavelength to shift outside of the 808nm needed by the crystals, and causing the brightness to drop.

There is one problem.
Beam goes out from the edge of the crystal.
Should I try to move crystal?

How close to the edge was it?

It is possible, but very difficult.

One of the members didn't like how his True 5 was working, so he pulled the crystals off to move them - and now he can't get any green at all!

I am trying to gather some information on how to do this for some of the other members. But whether it is worth the risk depends on how badly mis-aligned they are.

I wouldn't go yanking them off until at least we have a better idea of how good yours can perform right now!

 

[ReNNo]

@ReNNo:

What is the current to the driver? I understand your way of measuring is more accurate - the reason I ask is to be able to compare yours with others, as that is how everybody else has reported their's.

Sorry seoguy, but I removed driver and connected it to Lm317T to use in my 7 color laser project.
Module is glued, and soldering old driver will be difficult.

How close to the edge was it?

It is possible, but very difficult.

One of the members didn't like how his True 5 was working, so he pulled the crystals off to move them - and now he can't get any green at all!

I am trying to gather some information on how to do this for some of the other members. But whether it is worth the risk depends on how badly mis-aligned they are.

I wouldn't go yanking them off until at least we have a better idea of how good yours can perform right now!

It's right on the edge.
This is how it looks like.

 

[seoguy]

@MarioMaster:

You sure yours is 5.6mm? When I removed the retaining screw it showed that these were in fact 9mm diodes. The ring covers up a lot of the diode (it doesn't let the diode fall out either, when I removed the retaining ring the diode still would not come out)

From what I have seen, there appears to be two module types, which have different base styles. The high-power modules have a thin-walled bottom, with a brass lens-nut looking thingy screwed into the bottom, under which is a 9mm open-can diode.

The lower-power modules, on the other hand, have a solid, thick-walled brass bottom with a hole drilled in the center, and a 5.6mm open-can diode "pressed-in" to the hole (Aixiz-style, but deeper), without any retaining nut. So unfortunately, there is no way to replace the LD with a higher-power 9mm one.

There also appears to be different crystal styles, with the one coming with most of the lower-power units different than the one that came on my higher-power 100mw DX module.

 

[seoguy]

@ReNNo:

Sorry seoguy, but I removed driver and connected it to Lm317T to use in my 7 color laser project.
Module is glued, and soldering old driver will be difficult.

Hmm...let me think...

Well, from what I know of the schematic for the driver so far, nearly all of the current to the driver would be the same as to the LD...

For the output stage, the LD, driver transistor, and resistor are all in series across the power supply, so they should be drawing the same current...

And from what I can see, the current draw of the rest of the circuit appears to be fairly negligible...

I would have to give this more thought, but my GUESS is that it would be safe to take the LD current up a little bit, to 290 perhaps? Maybe even a bit more...

Do you have access to an LPM?

If you do end up taking the crystals off, I can tell you a way to tell for sure...on one of the pot-modded ones that was set to the same current level as the True 50, the LD was metered directly at 299ma to the driver, and was putting out 252mw. So if you pull the crystals, you could simply adjust the current to get the same output on the LD.

If I had a complete schematic, it would be easier, but I'm still waiting on an answer from one of the ppl that killed one of these to my post #135 above.

Originally Posted by seoguy
How close to the edge was it?

It's right on the edge.

On the crystals, let me see what I can find out. I have read that it's not a good idea to have the beam right at the edge of the crystals.

It's quite late, and my brain is a bit "fuzzy" right now, as I need some sleep...let me give this all some more thought.

 

[seoguy]

@fotonphorces:

I hooked the module and regulator up to a heat sink and saw an amazingly bright dot . The thing lit a match in no time.
After about 30 seconds of run time, I touched the big resistor on the driver and it was HOT!!

I read some topics on laserpointerfourms about this and it seems to be caused by too much voltage. I checked the voltage before, after, and during. The module was only getting 2.994V.

fotonphorces, some of us believe that the 200mw units are actually designed for only 100mw, but were "pot-modded" by the factory to over-drive the diode for higher power.:tsk:

While it is true that putting too much voltage into these things can cause problems, turning them up too high can also cause things to "heat up"!

One of the members here (disma) earlier reported that his 200mw unit instantly burned him at only 2.8V, so he shut it off, examined it, and discovered that the pot had been set by the factory all the way to MAX POWER! :wtf:

That is scary indeed, as even at 3V, this driver can deliver more than enough current to destroy the diode!

(This may not be as much of a problem for DX when they put these things into pens, as AAA's do not have enough horsepower to drive even my 100mw model fully!)

The stock driver likely consumes a volt or so itself.

Actually, no. There is no regulator "drop-out" voltage like you would have with a normal regulator design like a rkcstr or DDL. The LD is being driven directly off of the power supply, in series with a driver transistor (with only 0.3V C-E forward voltage at full saturation) and a 0.33 ohm resistor.

Perhaps increasing the voltage a bit could fix it...

DEFINITELY no! This driver can function at well under 3V - he's already feeding it more than enough (2.994V), any more will likely just cause further damage, as this driver does not regulate well > 3V!

After those pictures you posted of "vaporized" metal, I would think you of all ppl would be aware of what kind of damage this driver can do to an innocent diode if given too much power to play with!

However since it did work the first time it should work any other time with that setup.

You are correct - that LAST thing you want to do is feed even more power into the driver right now!

My question is what to do now? Did I permanently damage something?

I don't know if you damaged your diode or not. But here is what I suggest you do.

First off, hook a meter between your power supply (LM317) and the module (so you can measure the current going into the driver), turn it on for a few secs, and see how much current it is using. Then let us know.

If it is real high, try turning-down the pot (clockwise?) on the driver to a more reasonable current level.

For examples of current #'s (to the driver) -

My 100mw module was set by the factory at 530ma - and the big resistor doesn't even get warm!

Hemlock_Mike's 200mw module was set by the factory at 590ma, and put out 143mw of green.

When he pot-modded that same unit, he got the most power at 610ma, and now it outputs 160mw of green.

And whatever you do, don't go past 3V!

Try that, and then report back what you find-out!

 

[seoguy]

@roddenberry:

20 mW and 30 mW are precisely identical in every way...

I strongly suspect this may be true for all modules up to 50mw!

One funny thing I noticed is that on all three modules, the angle of the pot wiper is precisely the same (even at very close magnification).

That is concerning. I was hoping the lower-power units were just pot-modded DOWN - but now I'm beginning to wonder if they are just "sorting" the defective units based on how f/d-up they are?

Is DX selling us their trash???

Of course, this would require an extremely high failure rate, to generate enough of the lower-power modules to sell!

But given what we have been seeing with their "quality control" and careful assembly...

(rattle-rattle-rattle! LOL)

although one of the 20 mW has a slightly larger dot (i'll need to tweak the front lens a tiny bit maybe).

Perhaps you didn't shake it hard enough! LOL

All three modules have the same black pushbutton.

My higher-power one has a red pushbutton. But all of the lower-power modules I have seen, as well as the modules extracted from True 5's, they are all black. I think they may be color-coding these, for easy identification of the two different module types (9mm & 5.6mm) at the factory.

I'll have a quiet day tomorrow, so i'll be able to sit down and test all three modules to see how many mA do they consume at 3v, using a CR2.

Did you get a chance to test the current on these yet?

 

[ReNNo]

@ReNNo:

I would have to give this more thought, but my GUESS is that it would be safe to take the LD current up a little bit, to 290 perhaps? Maybe even a bit more...

I'll give it try.

Do you have access to an LPM?

No, don't have.

 

[fotonphorces]

fotonphorces, some of us believe that the 200mw units are actually designed for only 100mw, but were "pot-modded" by the factory to over-drive the diode for higher power.:tsk:

While it is true that putting too much voltage into these things can cause problems, turning them up too high can also cause things to "heat up"!

Right, I was not expecting much more that 100mw from this. I don't know if my pot was turned up all the way to start with...

I don't know if you damaged your diode or not. But here is what I suggest you do.

First off, hook a meter between your power supply (LM317) and the module (so you can measure the current going into the driver), turn it on for a few secs, and see how much current it is using. Then let us know.

Sorry but my meter only reads voltage.

If it is real high, try turning-down the pot (clockwise?) on the driver to a more reasonable current level.

For examples of current #'s (to the driver) -

My 100mw module was set by the factory at 530ma - and the big resistor doesn't even get warm!

Hemlock_Mike's 200mw module was set by the factory at 590ma, and put out 143mw of green.

When he pot-modded that same unit, he got the most power at 610ma, and now it outputs 160mw of green.

And whatever you do, don't go past 3V!

Try that, and then report back what you find-out!

I made this:
http://laserpointerforums.com/f42/diy-homemade-laser-diode-driver-26339.html

I had no luck. The only thing I'm confused with is where the positive and negative on the laser diode go. Everything else is strait forward. I left the original driver attached and I'm just "touching wires" on the 3 pins.

I also got a measurement on the pot before I messed with it. It was 9.02K ohm between the two closest terminals. I also found out that this pot never stops spinning in any direction. I've messed with some pots in the past but don't remember having one like this.
I decided to move the pot a little while the laser was on. As soon as it got brighter, I stopped turning it. Then it got dimmer by itself and the same steps were repeated with the same results. Also the resistor was hot the whole time.

I know all of these tests were risky and some would say I should not have done that, but the laser is still in the same state it was when I first posted and I was aware of the consequences that might occur.

 

[lazerov]

I have one of these modules. A 100mW one. It's a pretty decent module for the price. Some data:
Current - 560mA at a voltage from 2,7V to 3,4V. Pretty stable.
Beam diameter at exit is 2mm
At 5 meters it is 5mm (0,6mRad divergence)
Diode is definitely 9mm. Its leads are very thick.
Power is very good. I bought this expecting 50mWs. It exceeded expectations.
Heats up quickly.
I reverse engineered the driver and came up with this schematic:

(It appears that only one of the two Op-Amps is used)

Note: While I double-checked this schematic, it is possible that it still contains errors. Somebody must verify it.

Any ideas how to add TTL ability to this driver?

 

[alx]

Hi guys,

My order (placed 3 weeks ago) has status: "Processing - Contact us for the latest updates". Today, I received a strange response from DX:

Apologies that item sku.26886 is unstable and limited due to the shortage of the market supply, and we are not quite sure about the restock time of it. We just can fulfill the order once it is available again, please kindly let us know do you mind waiting for them, if not, please feel free to change them .
[end quote]

sku.26886 is 10mw green module. I am wondering what to ask for replacement: 5mw or 20mw version. Which one is not so problematic (shorter pending time before shipping)?

Regards,
Alx

 

[roddenberry]

Hi guys,

My order (placed 3 weeks ago) has status: "Processing - Contact us for the latest updates".

Uh oh... I think they either ran out of modules, or they pulled the remaining batch due to the high rate of returns... They seem from what i've read so far in this thread to have several QC-related flaws, including crooked crystals, rattling optics and many underpowered units...

I wonder if they still ship the modules of other power levels. :can: Anyway, I just made a boo boo with DX, i mistakenly did the dreaded double click on the shopping cart checkout of my latest order ($35 worth of adapters and tools) and it shows-up twice in my paypal account. Aargh!!!! I tried to cancel one of the orders but then I said to myself, bah, more trouble to cancel than to receive a bunch of spares! Oh well.

Robert

 

[alx]

I wonder if they still ship the modules of other power levels.
Robert

I ordered 200mW 532nm Green Module at the same day and It has been shipped last week. Now I asked about 5 and 20mw modules. Let's wait to receive an answer from DX to see if they are able to shipp other power levels and which one. Probably all modules from 5-50mw will be in "unstable market supply".

Regards,
Alx

 

[alx]

Hi guys,
sku.26886 is 10mw green module. I am wondering what to ask for replacement: 5mw or 20mw version.
Alx

I got answer from DX: "Sorry that we have checked both of the items are out of stock, would you like to change to other item? if you do not want to change,you can also ask us for a refund."

I asked now about 30mw and 50mw version! Let see if are still considered "unstable market supply" too and they are intending to retract it from the market...

Regards,
Alx