QTC flashlight - from scratch (non battery-crush)

[^Gurthang]

Fraz,

Any news on your latest builds? Love to hear more.

[TheFraz]

Progress is going good. I'm working on the AA version now, and I've made a few more key engine changes. In case you guys were curious, here's what QTC looks like after about 4k full compressions of various exposure times...



So the material can be too compressed and become deformed if it is exposed to large amounts of pressure for too long (it does still work approximately the same even deformed). However, I've since found a way around this little problem and added what I think is a good new feature to the engine - a fail safe that puts the light into direct drive when it gets to it's maximum level of safe compression. This should keep it from deforming. I'll keep you updated. Thanks for following the project!

-Fraz

[TheFraz]

I had time to take a couple short videos demonstrating the fail-safe in action. In the videos you can see the light switch to direct drive (when it slightly jumps in brightness), bypassing the QTC, when it reaches a certain level of compression. As you can see the light looks a bit beat up - the results of the torture testing the prototype has been going through. It holds up very well to drops and all kinds of everyday use so far.




The first video, the light is about 8 feet away from the door. The 2nd video it is about 20 feet to the wall.

-Fraz

[Mattaus]

Looks good

Any reason why you have to do so much turning before it starts to power up, or is that just how far you had it unscrewed in those particular videos?

[TheFraz]

Thanks! I'm turning it more initially because I've gotten into the habit of turning it an extra twist in the "off" direction to make sure it doesn't stay on a very low mode unintentionally. The full brightness range is still one full turn.

[gunga]

I'm interested. This is direct drive right? So when you say AA do you mean 14500?

[TheFraz]

Yes, it's direct drive voltage-wise. However the QTC acts as a great variable amperage 'driver.' It has great run times because of very small losses.

The AA version will be able to use a single 14500 or 3 x regular cells (with a 2nd body option).

[TheFraz]

Upgraded the engine again and reduced the length of the light to 4.3". Also did a drop test this afternoon from approx. 25 feet to concrete. The light passed no problem (not bad for a 255 gram light with no rubber bumpers - the "crunch" when it landed made me cringe a bit). We're going to go for a 50 foot drop onto concrete next, and hopefully keep going higher.
Here's a video of the current drop:

[TheFraz]

And here's the drop test from 50+ feet to concrete. The light passed again. I suspect it will be very difficult to get this build to fail because it has very few weak links. I think the most likely scenario is battery failure, but with the battery trapped between two springs and tightly hugging the sides of the tube, that is unlikely to happen as well. We're gonna try to find a 100' drop next and keep on going up til it fails. As of this point I feel pretty good about the durability of the design.

Here's the video. If you look closely you can see the light dropped right after I say "alright." (we jumped the gun a bit on the drop lol). It lands on the path and bounces into the grass..

[Empire]

Hello all,

Long time lurker here. Decided to post this as I am very pleased with the way it has turned out.

I wanted to design a very durable, very simple light. I've always liked the simplicity of QTC and have always been driven away from drivers and PCBs in LEDs, so I decided to try and build a light based around QTC.

Here is what I came up with:



Took a lot of trial-and-error and several failed attempts, but now it ramps smoothly and seems to be extremely efficient. Abrasion wear was a problem at first, and I also wanted to do away with battery-crush design. After several prototypes, it finally functions as I imagined it with no wear. Also attached are a couple videos of it in action:





Anyway, thought you might enjoy and good to finally post!

(7/2/2012) Update:

Here is a video of the version 2.0 QTC engine. The single full turn makes ramping brightness so much easier, and now I've gone through a couple thousand turns on the old engine and figured out the wear points and feel good about fixing them. The lines on the prototype show where a full rotation achieves full brightness.



(9/3/2012) update: Drop test from 25 feet.

I WANT ONE!!!!!!!!!!!!!!!!

[Mattaus]

Looking very good

[TheFraz]

Finished the third engine and body prototype today. Hopefully ironed out the last batch of bug fixes and added an xm-l neutral. I like the action of this one better - it doesn't require a full twist to max. It is also the shortest one so far at 4.0" even. Here is a pic (of the light next to a tk41) and video...even though all the videos look relatively the same. It is tough to gauge the brightness ramping because of the camera changing exposure.

edit: put up a video of the new light against a tk41 in bounce....just for something different.

[TheFraz]

Haven't posted in a while, thought I'd add an update. Got a chance to use my prototypes a lot over Christmas while our power was out for almost a week. The 26650 burned the whole time without a recharge (on mostly medium levels)...gotta love that extra capacity. Also updated the engine again and it's getting 5k+ full turns pretty easy without deformation. Here's a pic of the upgraded 26650 light I used in the power outage:



And here's a few pics of the prototype progression at this point with a MAg at the end for size reference.





The silver one at the end is an 18650 version of the 26650 light using the same engine. The 3rd one from the left is a bit beat up from drop-testing.

-Fraz

[TheFraz]

Finished another prototype. This time I tried my hand at anodizing with some decent results. I've gotten this 26650 version of the light down to around 3.7" and cut some weight as well. Below are pictures of the new light as well as the first prototype (both 26650 versions) so you can see the size difference. This new one is completely redesigned on the inside - I like the way it functions a lot better. Here's the pics:





I'll get up a video up of this new prototype soon. Aesthetically I like the way it looks better than the old version.

-Fraz

[Megatrowned]

Ooo, it's shiny! And I like the way it looks too What makes the 'feel' of this one better than the last?

[TheFraz]

Ooo, it's shiny! And I like the way it looks too What makes the 'feel' of this one better than the last?

Thanks! Yeah, I like the shiny look...it's a change. The pressure it takes to change the brightness feels more intuitive now - it's been tough to get it right. I didn't want the light to be too difficult to turn...but it couldn't be too easy either or it would risk accidental activation. It also has a better weight and feel in the hand in my opinion.

[xevious]

Looks to me like PEAK LED Solutions is the only commercial outfit putting QTC to serious use. I'd heard their Gen1 design was resulting in premature QTC failure, but the Gen2 design has supposedly solved this. So, it's very intriguing to see someone else come up with a design that maximizes QTC life. Is the QTC fairly easy to access and replace in your light? I'm thinking that if this is so, one can always stock up on QTC and replace as needed... and if once every year or so, that's not too bad.

[Darvis]

I would be all over this in brass and/or stainless steel... copper!??

Subscribing to this thread

[TheFraz]

Looks to me like PEAK LED Solutions is the only commercial outfit putting QTC to serious use. I'd heard their Gen1 design was resulting in premature QTC failure, but the Gen2 design has supposedly solved this. So, it's very intriguing to see someone else come up with a design that maximizes QTC life. Is the QTC fairly easy to access and replace in your light? I'm thinking that if this is so, one can always stock up on QTC and replace as needed... and if once every year or so, that's not too bad.

Yes, it has been one of my main goals to prolong the longevity of the QTC pill. It is quite difficult to get it right - but after destroying about 100 pills, gradually extending their life each time, I think I've come up with a good solution (the other good thing is that if the QTC were to ever completely fail or disintegrate, the light would still function). I also developed this light with the idea of making the pill easily user replaceable - so although it should last a long time, it is possible to replace the pill if you wish.

Darvis, I just sent in schematics to a shop to do a run of these lights, so they will be for sale soon. Just before they are ready (hopefully in a few weeks) I'll post a sales thread. Currently they are going to be 6061 aluminum and anodized HAIII, but I will check into using other materials as well. I will also describe more intricately how the light works in the sales thread - it uses a very unique engine that should make it very durable. Thanks for checking out the progress!

-Fraz

[octaf]

Any plan for Ti host ? Hopefully utilizing 18350.

[TheFraz]

Any plan for Ti host ? Hopefully utilizing 18350.

I'm currently working on a couple other models using different battery configurations (most recently a single rcr123/cr123 type). As far as the Ti, I haven't worked with that material yet, but I don't see why one couldn't be made. I'll discuss it with the machine shop.

[Megatrowned]

This is interesting! Let us know possible prices as soon as you know Will have to add this to my want list!

[xevious]

Good to hear it, Fraz. I'll keep my eyes open for your thread.

[octaf]

I'm currently working on a couple other models using different battery configurations (most recently a single rcr123/cr123 type). As far as the Ti, I haven't worked with that material yet, but I don't see why one couldn't be made. I'll discuss it with the machine shop.

Good to hear that.

18350 is almost the same as 16340 or CR123, just a little bit fatter, or thicker.

These days, I see lots of factory made CR123 lights actually having enough room for 18350 in their battery tube.

[TheFraz]

Here is a video I've been meaning to make for a while of the latest prototype. One of the things I am most pleased about is the size. At around 3.7" it is very small for a 26650 light that has a battery spring on both ends and an optic...at the beginning of the video I compare the size to a Wolfeyes Sniper (an 18650 light). The lower levels of brightness are shown at the beginning (they are usually the first to act up with QTC), then I show the full brightness on the wall and in the yard/grass. The engine build shown in this video is the best I've made so far - the piece of QTC inside is well used but not showing any visible imperfections in brightness ramping.



-Fraz

[xevious]

Excellent! You weren't kidding--the ramping is extremely smooth. I've seen videos of Peak's QTC lights that aren't this smooth.

[Diablo_331]

I've personally been very disappointed with Peaks gen1 and gen2 qtc lights. Granted I've only tried the Eiger and I've heard that the larger Peak lights tend to be smoother. My current neck light is a 40DD and the ramping is very smooth. I'm very happy with it.

This project looks to good to pass up! Good look going into the production stage! I've followed this thread from the very beginning and if funds allow then I'll be picking one up.

[^Gurthang]

Fraz,

Glad to see your latest prototype, very nice work and the ramping looks smooooooth! Keep up the good work, I'll keep checking on progress.

[TheFraz]

Thought I'd post a picture of my latest build. Added some knurling on the ends and HAIII. This one is also completely waterproof. I'll add a pic or video of it's use underwater later.



-Fraz

[xevious]

^ Nice, Fraz. Me like! Is that a lanyard slot in the tail cap? Would definitely help with anti-roll.