TicTac Flashlight

[Rick Dreher]

Dear home-brewers,

I stumbled across these clever, and certainly inexpensive DIY flashlight plans. I make no claims about its effectiveness, and question whether there’s a better way than permanently soldering the batteries, but figured it would at least generate some enhancements from this erudite group :-)

http://www.grynx.com/projects/tictac-flashlight/

[paul johnson]

Thanks Rick. Cute little design. H.O. (to borrow an automotive term) LED and wide flood angle (35deg) – looks like a nice LED – perhaps one of the newest generation of 5mm LEDs (like in the Photon Maxx) ???

Improving just a bit, but still keeping it quite simple so no regulator circuitry is required, I think I’d like to go for a double-throw switch. Why?

Put the 27ohm resistor on one side of the switch for when batts are fresh and near rated voltage, then put a lower resistance resistor on the other side of the switch for when the batts are closer to 1.0-1.1 volts (1.2v???) for each cell. This will give a “new life” to the LED, making it brighter again, but for a shorter overall burn time – not that much usable light is available near the end of useful batt life anyways, so, not really much of a loss, IMHO.

Possibly could get by with no resistor – need to be careful NOT to switch to this side before batt voltage drops significantly – i.e., closer to the forward bias voltage. Like zener’s white LEDs have a very narrow band where they respond somewhat linearly to voltage – too little = no output; too much = exceed max sustained current capability and will burn up. [sort of an “avalanche” region] Need to operate in the narrow band between the too little and too much voltages (around rated forward bias voltage, typically ~3.4 to 3.5 volts for white LEDs, IIRC – best check me on this) in order to operate without a current limiting resistor.

I’ve done something similar with a double-throw switch in a homebrew 9x5mm LED array headlamp I made a few years ago, but not for switching resistor’s, but rather for switching in a backup set of 3xAAA batts (3xAA were the primary source). when the primaries were run down.

[Jason Klass]

Pretty cool. Do you know what it weighs?

[paul johnson]

Jason, I don’t really know, but 95% (or even 98% ???) of the wt is the batts.

You can buy, empty, and weigh a TicTac container – i don’t know what it weighs.

The switch, LED, wire, and resistor is close to being neglible weight (esp. since there isn’t much wire – copper is relatively heavy).

The batts = typical wts = alk. AAA = 0.4oz each -AND- Li AAA = 0.27oz each

So, figure easily under 2oz with alk batts is my semi-educated guess – maybe more like 1.5oz, and maybe 1.1oz for Li batts. Not too shabby when one considers the battery life.

It would be neat (IF there is room) to add a second switch, resistor, and LED in parallel with the first. A second LED can really brighten up a little task/proximity light. Just compare the PT Scout (2LEDs) to the PT Eclipse (1LED) to see what I mean.

[paul johnson]

Rick, as a member of the BPL staff can you access my private email address listed in my account? If so, please email me there. I have a small private matter that might be of interest to you (no, it’s NOT about you adopting me so I can use your camera). Many thanks, pj

[Rick Dreher]

Hi Paul,

I don’t hold the secret decoder ring, but feel free to send an explanatory note along with your address as a support request, and Addie will be happy to forward it to me.

http://www.backpackinglight.com/cgi-bin/backpackinglight/support/support_issue_manage.html

re. Those cameras–hate to admit it but they are gathering some dust these days.

–Rick

[Jason Klass]

Thanks Paul. It seems like it might be haevier than my EOS. What do you think?

[paul johnson]

>>”…heavier than my Eos…”

Jason, No, I don’t think so. It’s 1/2 or 1/3 the wt of your Eos. Now, it’s an entirely different kind of light. The Eos is a 10mm Luxeon-type LED – great for distance lighting (e.g. nighttime trail navigation). The MYOG project Rick alerted readers to is a 5mm LED useful for proximity/task lighting. So, the lights have two totally different purposes.

[Bill Fornshell]

Is it about comet 73p bla bla bla that is supose to hit earth around 25 May with some of its fragments?

I just got the strangest email was it from you Paul?

[paul johnson]

No, Bill. Wasn’t from me. Anything I would send to you (if I even knew your email address) would have my name on it. I’d never email you anything that I would feel uncomfortable putting my name to.

Besides, I don’t know anything about a comet striking the earth 25May. But, I’ve heard that the sky is falling!!!

Hope you determine the sender.

BTW, great Alphamid you’re building. Hope you let us all know about its wind resistance. I’m not sure how its shape would handle 40-50mph wind gusts. That’s the only reason (oh…and bug netting – which I now understand can be added by Oware) why I didn’t buy one from Oware a year or so before I purchased the SMD Lunar Solo ‘e’.

[Robert Miller]

I accidently stumbled across the comet prediction this morning. It was made by one Eric Julien of the Exopolitics Institute. His complete paper is here. Here are a few quotes: “I received on April 7, 2006 a telepathic message from extraterrestrial friends.” & “[comet] would cross the plane of the ecliptic of the Earth at the date of MAY 25, 2006, the date received by telepathy!”

So tell us PJ, are you now or were you ever a member of the Exopolitics Institute? ;-)

[Scott Ashdown]

Hmm, interesting document although I don’t think i’ll be losing any sleep! I think I prefer to believe Chicken Licken, Foxy Loxy etc etc.. I saw them on the TV, so it must be true.

[paul johnson]

>>”So tell us PJ, are you now or were you ever a member of the Exopolitics Institute?”

No. I don’t even know what it is.

But, I was born on what is (or at least used to be) known as “Alien Registration Day”. They used to have TV commericials reminding all “Aliens” that they must register with the US Gov’t each year by that day.

As a young kid, I always found that funny, as I never thought that we had any “aliens” living on the earth. But, then, I was a dumb kid (who grew up to be a dumb adult), so what did I know??? – especially, if the US Gov’t was saying that they had to register – who was I to disagree??!!

When I was much younger, one long weekend I deecided to give this matter of “Alien Registration Day” great thought, so starting on Friday I set my mind to thinking on it, but still couldn’t figure out what the TV commercials meant, even by Monday morning when I had to be back at College!!!

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