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PL520 build, 1 of 3 lasers (very pic heavy).

Pi R Squared

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This last Christmas eve (12/24/2013) I purchased three hosts from Mrcrouse and started planning the three lasers, this is the first one of the three. I had intended to post this several weeks ago but I wasn't satisfied with the results. It was only a lens issue that I have since corrected and now the laser is perfect. The three hosts arrived only a few days after I purchased them from Mrcrouse.

The parts were purchased from DTR
520nm Osram PL520 Diode In Copper Module W/Microboost Driver & Acrylic Lens for $99 https://sites.google.com/site/dtrlpf/home/diodes/pl520-520nm-laser-diode

The host from Mrcrouse was $25.

And some additional parts from Survival Laser.
Survival Laser USA Home

Tools and supplied used are:

Soldering iron
Helping hands with lighted magnifier
Solder
Heat shrink tubing
Laser power meter
DMM

The total cost is approximately $150

If you decide to build an equivalent laser you can use any Mrcrouse host that uses a single battery and comes pre-wired with a battery contact board.

Lets begin with the package from Mrcrouse:



There they are. Lets begin with this one:



It is a recycled host from some other green laser with the addition of an impressive Mrcrouse extended finned aluminum heat sink.



Here is the host disassembled:



And some parts from Survival Laser that will be used in more than one laser.



Everyone needs at least one tripod to use with your lasers. I also prefer the Survival Laser extended focus knobs, they make it easy to focus while avoiding contact with the beam and they also accept a lens cap so you can avoid getting your lens dirty. I also like their external lens springs, they are much better than the internal ones.



Another photo of the tripod, the clamp is better than the tripod and for heavier lasers can be used on a larger tripod, see this other thread I recently posted: http://laserpointerforums.com/f44/targus-tripod-88257.html



Here is the lens cap, focus knob and external lens spring that I prefer to use on all my lasers.



The package from DTR containing the module with diode, driver and lens.



The module.



Lets separate the parts and have a closer look.



And swap the focus knob and spring. Wait a minute what is that!? That's not an acrylic lens! DTR has sent me a 3 element glass lens, maybe he ran out of the acrylic lenses or perhaps he upgraded my lens because I am such a good customer. Well lets see how it works out.



The tiny diode inside the module.



The driver.



The other side.



Now we can screw the focus knob onto the lens.



And slide on the external spring.



And screw it into the module.



Now we put the back part of the module back on.



And have a look at the wires from the battery contact board.



Then cut two pieces of heat shrink.



Slide them onto the wires from the module.



Solder the wires from the module to the wires from the battery contact board.



Slide the heat shrink in place and brush it a couple of times with the soldering iron.



Now its time to insert the module into the heat sink and tighten the set screw.



Almost finished.



Screw the heat sink into the host.



Slide the other part over the heat sink and screw it in place.



This is the 18650 battery I will be using for now, I don't recommend these but it will be fine for a low power laser like this.



Now I should have a complete working laser.



Insert the battery negative end first and screw on the tail cap.



It should be ready to go.



Lets see how it fits the tripod.



Here are some photos with objects for scale so you can see the size of the laser.



These other lasers were my first two builds. See the white links in my signature for more info. The one on the left is a C6.







So you can see its reasonably large for a laser that runs on a single 18650. Now lets get ready for some testing.



Now the first test.



Oh no! :wtf: The splash is brighter than the dot! If I shine it at a wall 10 feet away the splash illuminates an area 10 feet across! :wtf: I have another laser with a 3 element lens and it produces the same splash/bat wings effect but its barely noticeable, nothing like this! This is completely unacceptable and must be fixed.

OK now I will remove the 3 element lens and external spring and replace them with an acrylic lens and internal spring.



Now another small issue, to focus properly, the lens has to be screwed almost all the way in.



Not really a problem, just a slight inconvenience, if I screw the focus knob all the way on the lens, then I can't screw the lens in far enough to focus. I can just barely screw the focus knob on the lens enough that it will stay on but still be loose. I want to use it anyway just so I can keep a lens cap on it when not in use.



OK good enough, now its time for more tests.



Great! It now makes a clean tiny round dot. My cameras don't like this laser but after some difficulty I managed to get some photos.









Now for the LPM test.



And it reads 82.3mw.



It remained stable at 82.3mw for a long time before falling to 77.2mw by the time it was warm to the touch.



Here is one more photo of the dot unfocused, as you can see it is round, not rectangular.



The PL520 is a 3.8mm 50mW 520nm green laser diode. Over driven and with a G2 lens, DTR has reached power as high as 118mw.

I will return with another build in the near future.



And remember: Safety first, wear your goggles.

 



DTR

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Very nice build. I always enjoy seeing builds explained so well.:beer:
 

BowtieGuy

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Nice build Pi, great descriptive pics! :beer:
With that monster heatsink, duty cycle must = battery life!
 

COMMANDR

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Love the picture show, nice build with lots of info.
Thanks for sharing. Where did you get the laser nerd photo at the end?
Looks a lot like me just add a beard. :>)
 

ped

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+5 on your great build. Well done.
 

Zeebit

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Nice build. What a huge sink for that tiny diode.
 

gismo

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Likeable tutorial with a good sense for detail and explanation. A 100mW forest green build in that silver (heatsink) & black (host) combo must deliver very generous running times.

:gj: & :kewlpics: on this constructive review!
 
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Pi R Squared

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Sorry for the late reply. Thanks everyone for the kind words, I am glad you like it. This is my third build thread and I think I did better each time (the next one is coming soon). My goal with these build threads is to show people some of the easiest ways to assemble a laser from readily available parts. Looking back on it now I could have gone into more detail on a couple of things but it took me almost all night to post that so I had to stop somewhere.

I already have the hosts for my next two builds so they will be what they are, but I have to say now after my experience with this one, I now favor large heat sinks over small size. My last two builds have a very short duty cycle, they are too powerful for the hosts they are in, but then again what is better? Small size or long duty cycle? We each have to decide what we want. This one takes about 4 minutes before it feels only slightly warm so I think its safe to run it much longer than that at a time.

The last picture really is me. This is really what I look like when working with lasers or electronics, I am standing outside at home here somewhere deep in the forests of Washington state.

Its very nice now to have a laser with a visible beam that I can safely wave around inside without fear of burning anything.

For those wondering why the background in my photos is different, no I didn't move, I just move between two trailers from time to time.

Alan
 
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Seoul_lasers

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Great 520nm build. This will definitely be
My next wavelength!

Also excellent step by step construction documentation
btw!!

Inspiring build!

Thanx for sharing!!!
+1
 
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Pi R Squared

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Thanks guys for the complements, I appreciate it very much.

I have now posted build number 2 of 3, its a 405nm and you can see it here:
http://laserpointerforums.com/f38/s06j-12x-build-2-3-lasers-very-pic-heavy-89098.html#post1296670

One more thing about this green laser, I accidentally put the battery in backwards and got quite a scare when it didn't turn on but I quickly realized my mistake and there was no damage. I don't know if this driver has reverse polarity protection or not. I am thinking maybe I should label my lasers to remind me.

The third laser is coming soon.

Alan
 

BowtieGuy

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Glad to see there was no damage done!
It's a great idea to label all your lasers, especially if they don't all use the same battery orientation.
I label mine right near the tailcap, on the inside edge of the battery tube; this way, it's the first thing you see when you change or add batteries. :)
 




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