UV LEDs

[Packhorse]

Im looking for some UV LEDs to make an inspection light to look for hydrocarbons. I am guessing that the cheaper commonly available 395nm UV LEDs will not work too well judging by people comments about them not picking up stripes in bank notes.

Anyone know of a good source of lower wave length UV LEDs?
I probably only need a couple as its close inspections.

 

[Mick]

http://ledsupply.com/l5-0-u5th15-1.php

These should work better than the 395's

 

[wquiles]

Packhorse,

I have like 10x of the 5mm 360nm UV LED's. You can have them for free, just pay postage. Send me email if interested.

Will

 

[Packhorse]

Thanks Will.

email sent

 

[Packhorse]

The UV LEDs seem to have a very narrow wave length. Is this the same with UV fluros as wel?

 

[big vin]

i am experimenting with the Nichia NCSU033A, 365nm. It is really a high output, low visibility, but lights up a whole bunch of stuff. It is really a neat led. Perhaps will could build you a host for it, his priojects are all superb:hitit:

 

[wquiles]

Thanks Will.

email sent

Email and payment received - thanks. I will send you a follow-on note on Monday with shipping details. I am happy that you will put these LED's to good use :twothumbs

i am experimenting with the Nichia NCSU033A, 365nm. It is really a high output, low visibility, but lights up a whole bunch of stuff. It is really a neat led. Perhaps will could build you a host for it, his priojects are all superb:hitit:

Actually Packhorse is quite an accomplished light builder - I am sure whatever he ends up building will be great ;)

 

[big vin]

oops, my bad....

if the light is going to be used for things as inspection i would think the cost of the nichia led is justifyable (did i spell this the right way??)
I like it so much better than the low power emitters, or the 390nm ones etc...

 

[Firecop]

Speaking from experience, different hydrocarbons will fluoresce differently at different wavelengths. I'm a fire investigator, and use UV lights on a fairly regular basis to look for the best locations to take samples.

My partners and I have done field tests (we burned stuff :candle:) and compared the results: the nichia 365 does a fantastic job of hitting hydrocarbons without having to put on colored glasses. The inexpensive 395nm emitter I got from DX/KD is a good compromise-with filtering/colored glasses, you get some hydrocarbon fluorescence and good biological (blood, etc.) results, as well. Keep in mind, some things (carpet, for example) will fluoresce after burning as if an accelerant was used.

If it helps, I use both on my arson scenes - different leds will cross over and give you a useful spread of results.

On a related note, my wife and I recently did a UV night dive - the 395 nm emitter did an amazing job of fluorescing certain corals, tube worms and crustaceans. If you haven't done it, you should - it was a blast!

I hope that helps...

 

[RyanA]

I believe that the florescent lamps cover a greater spectrum, however the hand-held variety that I have used in the past were not very powerful. These show some promise however. (incan)

http://www.walamp.com/lpd/webstore/detail.tpl?partnumber=01294-U&cart=12553152004584650

I believe this one would fit in an A2 with a strion kit for a neat setup.
Also many Streamlights like the polytac.

and

http://www.walamp.com/lpd/webstore/detail.tpl?partnumber=01273-U&cart=12553152004584650

G4 sockets! (Kiu, D26 sunlamp etc.)

The call for price thing is always a bit scary though.

 

[Packhorse]

Thanks Firecop. I did think about using multiple wavelength LEDs but using just 360 and 395's leaves a big gap from the output graphs I have seen. Maybe some 375's as well??

Ryana: yeah the call for price is always scary. Also need to deal with a very narrow tank neck diameter of about 20mm.

 

[Firecop]

Sorry, I haven't played with or even seen any 370nm emitters.

On a related note, our crime lab detectives have an AC powered hand-held device that they can dial in different wavelengths. Granted, the detective I spoke with said that it cost several thousand dollars, but it'd be cool nonetheless, eh?

Good luck and please keep me posted with what you discover.

 

[Ken_McE]

Sorry, I haven't played with or even seen any 370nm emitters.

Would you settle for 360~365 nm?:

http://www.thefoxgroupinc.com/index.php?%20%20option=com_content&view=article&id=74&Itemid=68

The Fox people do a high-end, very narrow, very pure UV LED. They also have a graph of the output of a fluorescent UV tube

 

[wquiles]

Thanks Will.

email sent

Packhorse, the package with the 10x of the 5mm 360nm UV LED's left today via FedEx. You should have them before Friday ;)

Will

 

[Packhorse]

Thanks Will. That will give me yet another project for the weekend.

 

[bshanahan14rulz]

Will, were those the same ones as linked in Mick's post #2 above? If so, do you remember how visible they were when lit up?

 

[1 what]

If they are 360's you should see almost no visible light from them and you should not look at them to check. Shine them at some suitable "test material" instead. I hope they are as advertised since I've just purchased 20. Will is very generous helping out the way he did. Great CPF spirit:twothumbs.

 

[wquiles]

Will, were those the same ones as linked in Mick's post #2 above? If so, do you remember how visible they were when lit up?

No. I bought these about 2 years ago as part of a group buy. I did use a few to play with, and they had (if memory serves me right) little output in the visible range - but again, it has been a while ;)

Will

 

[Packhorse]

Thanks Will have them here now.
What current should I run them at?

 

[wquiles]

Thanks Will have them here now.
What current should I run them at?

Excellent - glad they arrived safely. From memory, something between 20-25mA is what I would drive them at.

Good luck :-)

Will