Weak Tea Laser

[fncceo]

Let me start out by saying this is my first post and I'm more than sure it's probably in the wrong place. I apologize. I hope though that I can be forgiven and someone can give me some advice.

I bought a laser module, brand New 445nm Aixiz Rkcstr 440mA Blue Laser Module, and glass lens from Hightechdealz and have been playing around with it.

I have to emphasize that this isn't a complaint against HTDZ or Kendrick. My order came very quickly and Kendrick has been a font of information and assistance. It's just I'm still not getting the results for which I was hoping and decided to cast my net out further.

My goal was to pop a few balloons, light some matches, typical stuff. Ideally, I'd like the beam to be visible in a dim (not totally dark room). But, what I've really got is a barely visible beam even in a totally dark room, and no ability to burn anything. I've focused the beam to a pinpoint at 6cm on a match, nothing (not even warm to the touch). The Aixiz case however is hot as a soldering iron (slight exaggeration) after just a few minutes.

At the seller's suggesting, I up'd the voltage from the 7vdc I was using to 12vdc (current stays constant at 440ma) but I saw no appreciable increase in beam brightness and after a few seconds the beam would dim and current drop to around 200ma. It wouldn't stay on long enough at that voltage to do any burning experiments.

I need to know if

a). My expectations for this type of diode are realistic (should this laser diode burn and be visible)?
b). Am I powering it wrong?
c). Does it seem like a defective diode or driver?

Thanks for ANY assistance on this.

 

[The Lightning Stalker]

That is the Rkcstr driver, correct? It sounds like the driver is overheating and the thermal protection inside the regulator chip is kicking in. Once the current hits 440mA, increasing the voltage isn't going to do anything except make the driver run hotter. Find the minimum voltage at which the current maxes out and go with that. Also, everything should be on a decent heat sink to keep it cool.

 

[fncceo]

That makes perfect sense.

That being said, is the performance I'm describing (barely visible beam and no match lighting or balloon popping capability) what I should expect from a $100 laser module that shows it doing just the opposite in the pictures the seller's website?

I wanted an impressive laser demonstration for my students, what I got was a yawn fest.

It's a bit frustrating. So far I've spent about $200 on this project and don't have anything I couldn't have got for a bunch of box tops and postage stamp.

 

[The Lightning Stalker]

If the tea is weak, one usually lets it steep longer. j/k

If you notice in the burning pics and in the video, it is hard to see, but the module is mounted in a heavy
duty heatsink. Also, with a linear driver, it is recommended to use 2x18650 cells with the 445nm
diodes, giving around 8.4V when fully charged.

I'll admit, lasers can be a very frustrating hobby at times. I dropped over $300 on an argon ion last
month, only to see nicer ones going for half that price. The first forays into this hobby are seldom a
success and there is a lot to learn. A big thing you have going for you is that you have found this forum
and if you stick with it, we will take good care of you.

 

[fncceo]

Thanks for the input. For the time being, I'm not concerned with the overheating UNLESS it's the overheating that causing the low output. I don't see how that can be given it takes several minutes of on time to begin heating and beam output is low (lower than I expect anyway from the moment I turn it on). I have made a copper heatsink where the diode will sit (I'll remove it from the Aixiz case)

Batteries aren't an issue for me because I'm using a bench power supply. It allows me to tweek voltage and closely monitor the current and I've tried it from 6v (just when the beam kicks in full) to 12V and as you suggested before, it doesn't change the current draw.

You mentioned using a linear driver (I'm assuming to replace the Rckstr Driver?) Will that improve the output? Where can I get that driver?

I honestly don't mind starting from scratch on this but if I'd do I'd like to get some honest advice on precisely what components I require for my needs.

Thanks!

 

[Tmack]

Starting from scratch is your best bet for sure. Google " dtr laser" he carries all the diodes and driver we use. If you want a bit of power I would suggest a m140 diode . He also has them prewired to drivers. He has a 1000mw version ( little more than match lighting. ) , that uses 3.7v lithium ion . Or he has up to 2000mw with two cells. All you need to do is connect the driver to you power source and your good to go. Now keep in mind the m140 is a very powerful diode and like I said will have a super bright beam, and be able to burn combustible materials at a good distance. ( several feet) this will require good eye protection, for you and the spectators.
He also has more tame options by way of 638 and 405 diodes providing a bit less power, but all are able to perform the balloon popping your looking for, in a prewired ready to go package.
Good luck. Don't forget to protect those eyes!

 

[fncceo]

That looks good. To begin -- and get a success under my belt -- I'm inclined to go with a full package pre-assembled then make my next project from scratch.

Would you recommend the...

1.7W 445nm Copper Blue Laser Module W/X-Drive & Three Element Glass Lens
$95

...as a stand alone module that will kick a balloon's arse, burn flash paper, etc?

I will be demonstrating this in a classroom and the students will be back at least a couple of metres. The room will be dim (but not dark -- dark rooms require more budget) so I'm wondering will it be seen? I will be wearing eye protection -- will they need any?

My eventual goal is to put together a demo with blue, green red and have my more advanced students design and breadboard a laser driver. But, I have to get one working first.

Thanks!

 

[Livinloud]

All you'd need to do is solder the leads to the contact board in the host you select and go. If you go the C6 route then I have a ton of heat sinks for them and I'm selling them off (I literally have over 150 of them lol)

 

[fncceo]

Sorry to be a noob ... C6?

 

[Speedy78]

C6 is a flashlight that a lot of people use to hold laser parts. If this is for demonstration purposes in a "lab" setting I would find a cheap lap style heatsink. It will allow you longer run times but wony be hand held because you would still need the power source. Its all about your planned uses for it really.

 

[Tmack]

If balloons and flash paper are all you need to light 1.7w is going to make a joke out of them!! Lol 1.7w will scorch your name in a 2x4 from 6ft.

 

[fncceo]

So, 1.7W is the difference between science teacher and supervillain?

Maybe after I'm done with my students I can hold the nations of the world to ransom with my own personal death ray ... it probably pays better than teaching.

I have to ask, is 1.7W safe for demonstration purposes? The school board can be so anal about blinding students.

 

[Livinloud]

HELL NO!!!!!! Over 5mW is unsafe for an unprotected eye. 1700mW is 340x more powerful than the safe limit and will instantly blind people!

Safety glasses are $45 each so $1125 for 25 pairs and those are uncertified glasses. Certified glasses are just shy over $2000 shipped........doubt this will be a school funded project,

 

[Tmack]

If you were to drop that laser and the beam passed over someone eye, they will be blind. Believe me I know. I'm blind in my left eye from a 1.5w laser.

 

[Livinloud]

If you are looking for a school safe laser then you are looking into the HeNe gas lasers. Most are under 5mW but they wont be very visible beams or be able to light matches or anything

 

[The Lightning Stalker]

Thanks for the input. For the time being, I'm not concerned with the overheating UNLESS it's the overheating that causing the low output. I don't see how that can be given it takes several minutes of on time to begin heating and beam output is low (lower than I expect anyway from the moment I turn it on). I have made a copper heatsink where the diode will sit (I'll remove it from the Aixiz case)

It is much better to leave the diode in the Aixiz module and put the whole module in a
heatsink. It's pressed in anyway, and unless you want to invest some more money in a
press set, it isn't going to be coming out easily.

You mentioned using a linear driver (I'm assuming to replace the Rckstr Driver?) Will that improve the output? Where can I get that driver?

The Rkcstr is a linear driver. I would stick with it unless you can't get it to stay at 440mA
while it's on the heatsink.

I honestly don't mind starting from scratch on this but if I'd do I'd like to get some honest advice on precisely what components I require for my needs.

Thanks!

My advice is always honest. I would not advise a burning demonstration for anything below
college level. We don't need anymore medivac helicopter pilots being blinded by dumb
kids with lasers. Once they see a powerful laser and what it can do, they are going to be
Googling to find out where you got it. If you want to demonstrate the properties of lasers,
burning things and clear air visible beams is not the way to do it. Now if this is a college
level class, that is a whole different story. Just be sure they know exactly what they're
dealing with and just how dangerous it is. Otherwise, stick with something under 5mW.
All it takes is one moment of distraction and a kid is going to get a hold of your laser and
start blinding himself and others with it. Don't think locking it up will keep it safe either,
especially at the high school level. Keys have a funny way of getting "lost" and ending up
in the hands of your students, but that is another story best left for another time.

Now for some advice on making your "invisible" beams more visible (I'm going to assume
you are sub-college level until proven otherwise). All you need is some smoke or fog from
a fog machine. There is also the trick with milky water in a fish tank, but the glass will
reflect enough to be potentially dangerous with anything over 10mW (yes, you heard me
right, that is ten milliwatts). Now also make sure that whatever it is mounted in is sturdy
enough that it won't turn when bumped. Think lab unit here. Then you should be all set. :beer: