1 oz. headlamp

JR, i’m really surprised your unit produced so much light on a single fresh 3v battery (~3.25v at beginning of life). I’ve gotten a glow out when i’ve experimented with it when i first discovered consumer LED lighting a few years ago (my attempts to relate theory to actual empirical examination), but not enough light to do anything useful.

Mike’s 3.5v forward bias voltage figure is correct for white LEDs (longer wavelengths can be as low as ~2.5v, IIRC – hence a single 3v batt source is sufficient to fwd bias the LED). Very little current is flowing through a LED until it’s fully “switched on” by the proper fwd. bias voltage. In this sense, LEDs operate sort of like one type of Zener diode (but in the fwd direction, unlike Zeners which operate in the reverse direction).

Well, generally/in most cases (assuming the experiment is conducted properly), there’s no arguing with the results of an experiment/test – yours being no exception. As Igor Sikorsky used to tell young engineers, “Young gentlemen, when the facts disagree with the theory, i urge you to accept the facts”, and i believe it was Jim Rhiele who said, “One test is worth a thousand expert opinions”.

Want to sell your unit, i’d like to do some experimenting with it?

Id rather not sell it. If I got a rare gem, Id rather not let it slip past…. Though I am a greedy capitalist American (or so my eastern european friends say) so if the money is right. ;)

I just started a new night job, so I cant take pictures until this weekend, but if I remember I’ll try to get some of the light itself, as well as its illumination levels.

Bonus, it wasnt a “fresh” battery. I stole it out of my broekn PT Scout.

JR, i look fwd to your pics.

regarding our similarly broken Scouts: i don’t know how i could have forgotten about breaking my first Scout about three(???) years ago (i know i mentioned this before). What i forgot to mention was…

I’ve been carrying it in my pocket for some time (yeah, i know, a real absent minded professor – if it was a snake, it would have bit me.). i don’t think of it as a Scout anymore, perhaps that why i forgot all about it (just had occasion to use it this AM at work, so it jogged my memory).

Some time ago, took some elastic material (my wife uses it in sewing – it’s about 1/4″ wide), and made a small elastic finger loop and secured it under the screw which holds the case together. I use it as a finger-mounted light source (and so stylish too!!! nothing says “techno-geek” quite like a finger mounted LED light ring!! supposed to be quite popular this upcoming holiday season.), freeing my hand to hold other things – new life for an old broken Scout (i’m generally too cheap to throw anything out – fix it or mod. it, much to my wife’s chagrin).

I guess i could put the hinge plate back on it (i think i know where it is – like i said i never throw anything out, well… almost never; spare parts are good for repairing the next one that breaks in a different manner) and then epoxy a ‘gator’ clip to the hinge plate so that i can clip it to my cap brim. [oh well,… when it comes to fabrication, Bill Fornshell i’m definitely NOT!!!]

I haven’t tried these, but had them in my bookmarks for possible future use.

Li-ion coin cell charger:
http://www.powerstream.com/licoin-charger.htm

Batteries are available also, but are a little high. If *SOMEBODY* wanted to get, say a hundred or more they would be much cheaper.

pj mentioned that the princeton scout could be removed from the headband and clipped to a cap/hat. The Atom Hybrid allows you to do the same thing and still only weighs 1 oz. and at the same price.