Tank007 E07 + QTC = BEST FLASHLIGHT EVER

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jekostas
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Tank007 E07 + QTC = BEST FLASHLIGHT EVER

Alright, after BestOfferBuy dropped the ball on getting me an E07, I was able to find another one for not too terrible a markup.  Combined with the QTC that Don sent me - $20, infinitely variable flashlight in an AA form factor.  Seriously awesome.

I'll have more info in a bit.

Edited by: jekostas on 03/09/2011 - 15:45
brted
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What is QTC?

jekostas
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brted wrote:

What is QTC?

Quantum tunneling composite

arenat
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Great ! Can't wait to see how you resolve it...

 

ezeqdb
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The first Quantum Flashlight? 

"no le temo a la oscuridad, la oscuridad me teme a mí"

mizjif
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ooo, I am interested in this! Maybe one of my 3 E07's could get this treatment Smile I do love the little lights, so improving on them would be amazing!

jekostas
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Alright - take 2!  Better quality, now with sound!

http://www.youtube.com/watch?v=z7ApU95Kj_8

Trancersteve
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I don't understand at all. Undecided

This light isn't infinitely variable out the box.

Where is the more info?

My little and new understanding from a brief read of that wiki link is that QTC is resistance based.. so the light will be demanding a chunk of power from the cell even when the brightness is minimal?

I wear my sunglasses at night.

jekostas
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The information is this (sorry, no good camera where I am to demonstrate):

There's a small piece of QTC glued in to the head of the flashlight in the positive connection terminal.  As I twist the base and engage the plunger mechanism, the QTC is compressed and more and more current flows through the now-connected circuit, feeding the LED greater and greater current.

The thing to remember is that batteries do not push current, the LED pulls it.  At minimal brightness, there will be minimal current draw.

mizjif
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and where can one acquire this QTC that you speak of?? Smile

angusinalberta
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You can call it a QCT or anthing else you want but it's still just a fancy variable resistor.

Resistors can only drop voltage one way - by converting electical potential into heat.

So you're still draining the battery like mad when you choose a low light output. But at least your hand stays warm.

It's far better to stick with dc-dc converters for their energy efficiency, and forget dropping resistors.

Cheers,
Angus 

 

srfreddy
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uhm.... Sorta. The Fv of the LED drops with current rather slowly, so the LED is actually drawing very little current at a slightly lower voltage. Yes, the QTC is dissapating some energy, but its quite trivial.

tbenedict
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Any pics of that QTC?  Also, where do you get them?

frills
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I never considered that the battery squasher design of the E07 could be a benefit. I have to try this with mine.

jekostas
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tbenedict wrote:

Any pics of that QTC?  Also, where do you get them?

There's not really much to show - it's essentially a dark grey/black 4mm square of squishy rubber material.  I got a couple of spares from Don here on the forums.

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jekostas wrote:

Alright - take 2!  Better quality, now with sound!

http://www.youtube.com/watch?v=z7ApU95Kj_8

So where do I send my E07 so you can make it just like yours? :bigsmile:

 

Don wrote:

"But as I said long ago, you are more likely to be killed by a dead fish dropped by a seagull in the Sahara Desert than by a lithium ion

Don
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Or I could send you a few pills of the stuff to play with. It is cheap but there is a rather large minimum order of the stuff so I had to buy about 70 of the pills. From memory the pills are around 35 cents each and they weigh next to nothing so postage will be cheap.

 

While it isn't 100% efficient, it is operating more or less as a tap here, passing only so much current depending on how squished it is. When it is unsquished it has a very high resistance and as you compress it the resistance falls.

I doubt it'd work well in high power applications, the heat has to be dissipated inside a 4x4x2mm chunk of rubbery stuff.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Don
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tbenedict wrote:

Any pics of that QTC?  Also, where do you get them?

 

http://www.mutr.co.uk/product_info.php?products_id=1144

 

But they have a rather large minimum order.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

Essexman
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What do you use to glue the QTC in place?

Match
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Awesome mod, Jekostas!

Don, if you have a few extra, I'd love to buy a few off of you. I've been wanting to experiment with that stuff for awhile now, but have had too many irons in the fire lately.

Don
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Match wrote:
Awesome mod, Jekostas!

Don, if you have a few extra, I'd love to buy a few off of you. I've been wanting to experiment with that stuff for awhile now, but have had too many irons in the fire lately.

 

No problem. PM me and we'll sort it out.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

jekostas
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Essexman wrote:

What do you use to glue the QTC in place?

The glue turned out to be a bad idea, as I ripped one piece because of the constant friction.  Right now the QTC piece I have in my E07 is just being held in place by the friction of the battery.  The E07 has polarity protection in the form of a small cavity in the pill where the positive post of the battery goes - it seems to work well enough.

I'll have to think up a sandwich-type holder for the tail section.

Don
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That was the problem I came across.

A couple of thin 14-14.8mm conductive discs sandwiching it would be the best bet. I've tried various coins with no success. The material is very soft. 

Looking at a UK 5 pence coin, it is a little too large, but close enough I can file it and is thinner than the pill. A 4mm hole in the middle of that might work.

 

This is just thinking at the keyboard which I was always taught in my Computer Science classes thirty years ago was a Very Bad Thing To Do.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

srfreddy
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The 38DD had a foam centering ring. 

frills
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Unless my E07 is unusual, there should be a foam spacing ring at the bottom of the battery tube that keeps the battery from touching the -ve contact when you twist the tail into the locked position. I figure one of these QTC pills would stay put a little better if you were to put it into that ring rather than at the +ve button. It also wouldn't be subject to the head's twisting action if it were glued down there.

Don
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Neither of my E07s have those foam rings in them. Would be nice if they had....

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

jekostas
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frills wrote:

Unless my E07 is unusual, there should be a foam spacing ring at the bottom of the battery tube that keeps the battery from touching the -ve contact when you twist the tail into the locked position. I figure one of these QTC pills would stay put a little better if you were to put it into that ring rather than at the +ve button. It also wouldn't be subject to the head's twisting action if it were glued down there.

Yeah, my E07 doesn't have the foam ring either or that's the route I would've gone.  As it is I use the tail lockout switch to turn the light on and off instead of the head.  Doing it this way also shields the QTC pill from twisting action.  It's the compression force of the battery that causes the friction problem.

frills
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That's sad news if I ever want to get another one. I'm not sure how the light would avoid battery rattle when off without it.

Don
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The foam ring was the way to go!

Mine is far from pretty, but it works. I just cut a thin piece of foam I had lying around and made a small hole in the middle to hold the QTC pill. Works brilliantly!

Thanks folks, especially frills, for the inspiration.

 

Told you it wasn't pretty. I put a tiny dot of epoxy on the foam to hold the pill in place. Didn't work all that well. A certain amount of care was required when inserting the foam.

Foam and pill

 

Video uploading as I type.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

jekostas
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Don wrote:

The foam ring was the way to go!

Mine is far from pretty, but it works. I just cut a thin piece of foam I had lying around and made a small hole in the middle to hold the QTC pill. Works brilliantly!

Thanks folks, especially frills, for the inspiration.

Head or tail?  Any pictures?

Don
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jekostas wrote:

Don wrote:

The foam ring was the way to go!

Mine is far from pretty, but it works. I just cut a thin piece of foam I had lying around and made a small hole in the middle to hold the QTC pill. Works brilliantly!

Thanks folks, especially frills, for the inspiration.

Head or tail?  Any pictures?

 

Tail. Pictures and YouTube bit uploading as I type. The video may take a while to be available - YouTube can be horribly slow sometimes.

 

See Post 28 above in a while.

 

The numbers from my light tests are always to be found here.

https://spreadsheets.google.com/ccc?key=0ApkFM37n_QnRdDU5MDNzOURjYllmZHI...

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