Anyone familiar with UV LEDs?

[sergioq]

So am using UV LEDS from Radio Shack* Using them, I can see flourescent items (real teeth vs. capped...hidden logos on Credit Cards, etc.)

But when it comes to US currency, I can only see the hidden strips, but not their unique colors.

So am guessing I need a BRIGHTER LED(s)? Anyone with any previence experience, would love to hear your advice.

Many thanks,

Sergio


*5mm High-Brightness Ultraviolet LED (2-Pack)
3.3V typical
4.0 max

 

[BradtheRad]

After seeing your post, I have entertained myself for a few minutes by looking at US bills under my UV tube lamp. It shows up the unique colors of the embedded strips. $5, 10, 20, 50.

Some color strips are brighter than others. Some strips are easier to see from one side of the paper, some easier to see from the reverse.

Sometimes the strip is easier to see when I hold the bill between my eyes and the UV lamp.

Since your LED can bring out the other hidden items, it's hard to understand why it does not bring out the embedded color strips.

 

[keith1200rs]

My guess would be the wavelength of the LEDs is incorrect.

Keith

 

[sergioq]

My guess would be the wavelength of the LEDs is incorrect.

Keith

Thanks. I have Googled this, but still fallen short of finding an answer. Maybe I am using the wrong search terms?

But if anyone knows what the proper answer would be, or what I should Google...anything.

I would very much appreciate the help or hint.

Sergio

 

[keith1200rs]

I don't know about the USA but in the UK the recommended wavelength is 365nm. Cheap UV LEDs are unlikely to be 365nm. The shorter wavelengths are the most expensive.

Keith