More Tests of UV LED flashlights and LED's
Uploaded 11/13/16

Here we do some additional tests with both the spectrograph and direct lighting of UV mineral specimens. The newest addition to the UV light line up is the just completed 9 LED mineral lamp I built this week, seen below as the small black box in the lower left corner of the test bench. The results are good - a strong performance on long wave UV minerals!

Left: Bench setup includes the huge 100 LED scorpion killer flashlight on the upper left, in the pin vise pointing at spectrograph input is the "Purple LED flashlight" which is an original scorpion lamp sold many years ago when the first came out. Then the blue flashlight is a standard 27 LED white lamp used for full spectrum views.

Finally the new unit is the black box in the lower left, which is 9 Adafruit UV LED's I put in a housing with a 9v battery and switch.

The spectrograph is in center, and laptop is recording short 100 frame AVI files of each spectrum for low noise integrations.

The Big compare. Click to enlarge to full size.

The results show that the old Purple LED light was not as far into the UV as the two newer units below it. I drew a straight edge on the images so you can see this. The Adafruit LEDs are apparently identical to the ones used (as far as pass band) in the 100 LED scorpion killer lamp.

Finally, a solar spectrum is aligned on the bottom to show the relative positions of the UV outputs vs visible light. Second order spectrums have been cropped off, as the UV lines appear again superimposed on the IR data...

Left: now in the old photo dark room, I set up to show what each lamp did at a distance of 10 inches and the same photographic exposure - 1/500 f/5.6. This is the white light room light on view of the test setup.

On the left is a chunk of calcite that glows a bit white under long wave UV, and on the right is a specimen of hyalite opal that is very active in long wave.

Left: Now here is with the 100 LED lamp - fills both samples with a huge 4 inch beam. The Hyalite is glowing blue, but the calcite is pale.
Adafruit 9 LED has same intensity as the 100 LED, but over a smaller 2 inch area. Still, a very nice performance!
And the old purple 5 LED scorpion lamp? Sorry, time for retirement!