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[at-l] New Photon Micro-Lights
A few months ago I wrote about Photon Micro-Light (tm) miniature
flashlights which use very bright light-emitting diodes instead of
conventional bulbs. At the time I had not tried the green or white
variety. Someone emailed asking about them, and I promised a review:
Photon lights are roughly the size of walnut half-shells. They are
available in infrared, red, yellow, green, blue and white; I've used a
yellow one for a year (with original battery).
The green LED is brightest of all, but the white LED is far better than the
pure colors for general illumination. It's actually a solid-state
fluorescent lamp: A blue LED excites a white phosphor. It is surprisingly
bright; looking directly into it is painful. The beam is wider and more
uniform than that of most other LEDs and flashlights.
Batteries are widely available (Radio Sh**, K-Mart). To replace them, pry
the case halves apart with a knife blade. The device is extremely simple:
Compressing the flexible spot on the housing squeezes the battery between
the leads of the LED.
The physics of LEDs is such that the shorter their wavelength, the more
voltage is required to produce light. The white Photon "Maximum Overdrive"
model contains two coin-shaped 3-volt lithium cells; others use a single 3v
cell. The actual operating voltage of the white LED is about 3.8 volts;
the internal resistance of the battery is significant in the design. In
other words, if you dissect a Photon and build your own lamp with larger
battery, you will need a series resistor or else the LED will be destroyed.
Since the white LED requires more than 3 volts, it is not transplantable
into flashlights which use two 1.5-volt cells.
The Photon is not waterproof, but could be made so by gluing the case
together with "Shoe Goo," silicone ("RTV"), or other glue that stays
rubbery after it dries. Alternatively, you could put some kind of
nonmelting grease inside the case.
To make the light stay ON hands-free, use a small Maillon Rapide as a C-
clamp to compress the pushbutton. (Maillons Rapides, a.k.a. "quick links,"
resemble mini-biners with screw gates. They are made in France, used for
joining chains, available at most hardware stores). The one I use is 40mm
long and has an 8mm gap at the gate. Try before buy.
The Maillon Rapide forms an adjustable tripod for positioning the light for
hands-free use. I have also used it to clamp the Photon to the brim of my
hat (great for reading). If you do the hat trick, tie the pieces together
with string to prevent loss if they get bumped and fall off. A neck
lanyard is a good idea in any case. A blunt-nosed alligator clip might
also work for compressing the switch and attaching the light to other
objects.
Weights (from electronic scale in post office lobby):
Photon lights (without keyring)
yellow 0.2 oz.
white 0.3
Maillon Rapide 0.3
Forthcoming models include one with a slide switch, a transparent housing,
and a multi-LED headlamp which will achieve variable intensity by selecting
the number of LEDs illuminated.
Manufacturer:
L.R.I. (Laughing Rabbit Inc.) [allegedly doesn't sell direct]
P.O. Box 34
Blachly, OR 97412-0034
http://www.photonlight.com
The LEDs are made by Nichia of Japan.
http://www1a.meshnet.or.jp/nichia/index.html
Nichia expects to double the efficiency of their white LEDs (now 7.5 lumens
per watt) in the next 1-2 years.
Sources:
LITES
P.O. Box 279
Molino, FL 32577
904-587-5172
http://www.photonlight.com
I got mine from:
Inner Mountain Outfitters
Route 1 Box 263
Greenville VA 24440-9727
imo@cfw.com Phone/Fax (540) 377-2690
White, blue or green Photon $15.00, other colors $10.00.
$3 shipping for any reasonable quantity.
_..._
Comments from "speleonics" (mailing list of cave-related electronics):
Photons were taken up on a recent Space Shuttle mission, and got rave
reviews from the astronauts.
A doctor with strong interest in wilderness medicine uses his white Photon
for numerous medical-inspection purposes.
"...holding it on with my teeth... I got tired after 10 minutes."
"I added one of those 20 cent reflectors which are available for LEDs
at any electronics store and it improved the usefulness..."
"I jammed one (Photon white) on, and found it went about 5 days."
"Still enough light to read by after three days."
_..._
Summary: White LED flashlights are bright enough for most backpacking
purposes, have very long duration, and are significantly smaller and
lighter than comparable flashlights with incandescent bulbs. White LEDs
are still new, expensive, and improving. They will eventually replace
incandescent bulbs in many low-power applications. We may expect many
variations, including efficient electronic regulator/driver chips made
especially for LEDs.
-- Frank reid@indiana.edu
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