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DIY 1W 808nm Labby fired up first time VIDEO

sbdwag

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Just got my new project going tonight . Made a 1W IR Labby using some diodes I acquired from Chris.

Im using a Meredith Module to colllimate the 9mm diode. As you can see from the video Im getting about 1.17a's thru the diode right now measuring across a 1% 1ohm power resister

Im viewing this thru the viewfinder of my Nikon L18 camera.

http://s419.photobucket.com/player....bums/pp279/sbdwag/DSCN0199.flv&fs=1&os=1&ap=1

I have some questions.

1.) Right now It will burn great close up maybe 75 mm away. But at two feet will not burn anything as shown on video. I am now learning about multimode laser beams. Ah... I am only a grasshopper.

2.) What kind of lens can I purchase to focus the beam to a pinpoint at a great distance away from the emitter.

regards
sbdwag
 



ElektroFreak

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I like it! Nice build..

The minimum requirements for collimating a multimode diode are a cylinder lens for the fast axis and a convex lens for final collimation. Those meredith modules only have convex lenses, so the best you can hope for is a thin line.

The raw output from a laser diode diverges faster on one axis than the other. The picture below will clarify:


Source: laser.physics.sunysb.edu/~xueqing/webreport/p2.htm

The wider axis is the fast axis and the narrower is the slow axis. Multimode diodes have vastly different requirements for collimating both axes down to a low-divergence square beam, hence the need for multiple lenses. Once you've gotten rid of most of the astigmatism and you have a square beam, then you can just use another adjustable convex lens for focusing. A magnifying glass works great also.

To get a clearer understanding of everyhing described above and for more advanced methods, read this paper.
 
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billg519

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Nice clean impressive build! Chris may have cylinder lenses, also there is surplusshed.com so you should be able to get some and experiment.
 

sbdwag

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Elektrofreak

Thank you. I figured before I jumped into something bigger I would get my feet wet with alittle less power.

regards
sbdwag
 

lasersbee

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Your logic is impeccable...
Start small... learn by your mistakes... Go bigger..:gj:

Jerry
 

mauswiesel

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HAHA !
i saw on your vid a 0:47 seconde that the focus point (rectangular one) of the diode, have in middle a big black line in it. I have the same black line.
Is it a damaged diode or any 808nm diode (including cmount) have this black line? ????
 

sbdwag

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Re: DIY 1W 808nm Closeup photos

Heres some closeups of the labby

Power to the unit was a old switching wallwart that was used to power a Kodak camera cradle. It was 7.0v 2.1a... the perfect size for this project I got very lucky finding it.

Someone made the comment that the heatsink was to big. But I can tell you that I needed every bit of this sink. It gets very warm not hot to the touch.

Because I was using what was on hand I did not have any blinking leds for the "lase on" indicator so I added a 555 timer to it.

I also added a 40ma header for a sighting 5mw laser which is attached rather haggardly with electrical tape for now not sure If I need it though.

Basically this is the limit of the LM317 power supply IC. Im using a 1ohm series parallel combination to reduce power thru each resistor to provide 1.24a to the diode. This setup would consistanly produce 1.48a's but I opted for a fixed current supply with only a 1ohm resistor. To use a pot I would have had to go to a Ohmite wirewound variable resistor setup and I did not want to have to wait on it.

The Copper sink never gets warm even after a hour of duty. The LD is case positive so it has to be insulated from ground thus the rubber mat it is setting on. I have 5/16 Nylon bolts coming thru into tapped holes in the sink to lock it to the case.











Regards
sbdwag
 
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bobhaha

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Very impressive.. nice clean build, hope to see the 5+ W version soon LOL!!

-Adrian
 

sbdwag

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Very impressive.. nice clean build, hope to see the 5+ W version soon LOL!!

-Adrian

Not really you should see the bottom of the board :yh:. Yep you guessed it my next project will be a 5w c-mount. Much more involved I will need to use a 5v 10a switching power supply to provide enough current for the diode. Also everything is going to have to be bigger

Regards
sbdwag
 

lasersbee

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Re: DIY 1W 808nm Closeup photos

Someone made the comment that the heatsink was to big.
There is no such thing as a Heatsink that is too big... for cooling...
The only situation I could see would be that space would not allow it...

Waiting to see your next build...;)


Jerry
 
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roddenberry

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A very nice build. Looks very professional. What is the diode you use in this project? And if I may be bold as to ask how much did the 1W diode set you back?

You next 5 W project is going to be a powerful, dangerous laser with no visible beam. I'm sure you already have adequate eye protection? :D

Robert
 

lasersbee

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1 Watt IR Laser Diode from Chris=heruursciences

Jerry
 




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