First Mod, guarenteed offensive to those with skil

Ok, so i got a cheap 7 LED UV Flashlight from Ebay

It is supposed to run on three AA's. Now i had purchased a little Key Chain light from the same seller, same wavelength (385nm) so i'm guessing that they were the same LEDs. The key chain light was a single LED run on two button 3 volt batteries. So I got to thinking, surely, 7 LEDs could deal with more than 6 volts and be brighter than the mere 4.5 that was being offered by the 3 AAs. Plus i don't have any fresh AAs and i'm impatient. So i started looking around, and i have some copper wire... ok good. I also have

A Lithium Ion battery backup for my digital camera. Now we are in business.

So, simplistically, i hooked one length of copper wire to the positive contact of the flashlight, and i wraped some around the threads for the negative.

dirty, but simple, nothing long lasting here.

Then i merely pressed the two wires to the appropriate contacts of the battery, and voila,, crime scene quality UV light.

So i basically just did this to prove that i rembered some things from when i dabbled with electronics a few years ago. But so far it's not looking good, i joined this group a few days ago, i've already ordered parts for my MiniMag, and i've started doing thins like this, and i'm going to stop by RadiShack on the way to the grocery store.... just to look.

One more pic to show the led configuration


On a side note, i know that electricity can be dangerous, and the only reason i even thought to try this with out more reference was because of the low voltages i was working with.

Neat!

As far as the "go to RadioShack just to look" club...welcome! I've been frequenting RadioShack a lot in the past few years, because I recently got into CB radios, and RadioShack was one of the few places that still sells the necessary stuff like SWR meters for calibrating an ajustible antenna. GMRS was just approved for use in Canada in '04 so I spent some time looking at those too, other that those purchases...I love to just fiddle with the doodads and look at all the adapters and oddends to see what I could put to use.

Just be carefull.. UV is dangerous, and overdriven UV WILL die much quicker.
You mean you actually held off a few days before you started getting stuff. WOW

Jeff

yeah, being in between paychecks can have a significant ability to moderate the speed at which i pursue my hobbies /ubbthreads/images/graemlins/smile.gif Would you happen to know what sort of voltage would be good for a 7 led aray like this? Is it supposed to go with the 4.5?

Its not the voltage but the current, LED's are current driven devices. Standard high output LED are happy at 20-25mA, will run up to 50mA. UV LEDs are most happy FWIR at 15mA or so. so the total current draw should be around (20mA x 7 = 140mA max), voltage source dosent matter. With a big enough resistor you could run the LED array off of 100VDC (if you REALLY wanted to)
I have a 8 LED 400nm UV light that runns 3x'AAA' batteries. I put an 18ohm resistor on EACH LED, this limited the current to about 25mA (HARD OVERDRIVE)..
You would need a multimeter to see what they are drawing in current, and somewhere around here is a site link for a resistance calculator that could tell you what to use.
Bice light BTW, all my UV's are 395-400nm, and I really want to go 375-385nm.
Jeff

The 385nm is much more fun than the 395-400nm's. Almost in a scary way. But it is good at keeping up on my ferret's potty training behavior. I know that LRI makes a Photon with a 375nm led.... so how would i take a key chain light like that and modify it to work in a MiniMag? Would i use two 123s, and a longer spring... that would give it the 6 volts... but you said that wouldn't matter as much, this might be over my head... but any suggestions?