QTC flashlight - from scratch (non battery-crush)

[TheFraz]

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.



(9/14/2012)update: Finished the v3 engine and body design. below is a pic beside the v1 design and video of it against a tk41




5/4/2013 Here are a couple pics of the prototype progression. From left to right is the oldest prototype to the newest.

[jabe1]

That looks great! How about a few more details?
How is the QTC protected? What battery is it using? Which emitter?

[TheFraz]

That looks great! How about a few more details?
How is the QTC protected? What battery is it using? Which emitter?

Thanks ! I'll take some pictures of the engine and the light disassembled when I get a chance. It is driven by sort of a series of pistons. I wanted to be as minimal as I could with the design. I try to stay away from threading/screws/glue etc as much as I can - it's only threaded in one place. I wanted it to be simple to assemble/disassemble. Uses an XM-L and a 26650 battery.

[Mattaus]

I wanted to be as minimal as I could with the design. I try to stay away from threading/screws/glue etc as much as I can - it's only threaded in one place. I wanted it to be simple to assemble/disassemble. Uses an XM-L and a 26650 battery.

Sounds like the perfect light to me! What are the dimensions? What material is it made from? Being QTC I imagine it is a twisty and has variable brightness?

I'm watching this thread intently now :-)

[Harry999]

Now that is really interesting. I am a big fan of Peak lights which use QTC material so I look forward to seeing how this develops. I assume this could be built for any battery size...

[TheFraz]

The light is 4.85" x 1.6". I meant to overbuild it, but it may have overdone it a little. The walls are very thick, around .25" on the battery tube, and it's pretty heavy - although I like heavy . Yes, it can be done with any battery type (as long as the LED doesn't get too much voltage from the particular battery setup), and it is a twisty with variable brightness. Works very similar to a wall dimmer in a home. I'm working on a couple more designs/builds now with different reflectors and battery combos. There's just a couple more small bugs I want to iron out to help with the feel and get the most out of the setup.

Here is a pic of the prototype beside a TK41. Both are on high (TK41 is on turbo), 6ish inches from the wall.

[^Gurthang]

Can't wait to see & read more about your work. I've been interested in QTC since I first read about it here, your 2nd video is short but I see how well the light ramps. Keep all of us informed.

[jabe1]

What is the finish on the light? It looks great!

If you're not careful here, this could become a side business for you.

[Tofty]

Also looking forward to seeing how this torch works in relation to the qtc control.

[TheFraz]

I'm out of town, so I can't put up visuals atm, but to answer your questions from earlier: It is made of 6061 aluminum and finished with Gun Kote. I like the way the matte finish on the Gun Kote looks (it was also the only aluminium finisher I had laying around). And I am trying to make this light look and feel kinda like a gun engineering wise - well built (even overbuilt) and easy to break down and clean if necessary. However, I am looking into more durable solutions for the finish as well.

As far as the way the qtc brightens and dims this prototype, it works very smoothly with no flickering or artifacts. A good example if you have a QTC pill - make a circuit with wires running to and away from an LED. Put the pill on the + end of a battery and the - wire on the negative end of the battery. Press the + wire into the QTC directly, it gives you an idea of what the material is capable of. Ramps like butter when you don't have to worry about movement of the pill or shearing force. I'll try to make a little better video showing the operation if I can get a little time tonight.

When I get back home, I'm going to make a couple small adjustments to the build, mostly involving tactile feedback from the twist (also a better reflector/optic and warmer LED). Looking forward to tweaking it a bit more!

Thanks for the interest guys!

[Harry999]

Looking forward to seeing future developments especially if you eventually consider making these available for interested CPF members. Hint Hint!

Sent from my smart phone using Tapatalk

[Harry999]

Double Post - I need to stop using my phone to post here!

[borrower]

+1 to seeing the guts of this... one of my many not-done projects is to QTC a flashlight. There's some of my failure/success with qtc here: http://forums.mtbr.com/lights-diy-do...ty-730630.html
(you might have to register to see pictures in that thread, but they don't spam you)

[TheFraz]

Finished work on a new engine today - a big upgrade over the first one. The brightness level change is much more smooth. Action also feels better. You can turn it up to full with one hand now. Also reduced the number of solder points to 2 and took it down to a total of 2 screws (I hate extra parts). I think I can also shorten the light a little more on my next upgrade.

Here's a more detailed video of the operation of the light:



Now to work on the AA version...

[Mattaus]

Now to work on the AA version...

NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!

[Coup de Grace]

I'm keeping an eye on this thread. I have a QTC Peak in my pocket right now. I'm hoping the QTC holds up.

[Harry999]

NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!

+1

Sent from my smart phone using Tapatalk

[TheFraz]

NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!

NiMh or alkalines for the current model (I like the idea of having one that uses standard batteries). The QTC doesn't stop the voltage, so I have to keep it in the right range or *poof.* I think I can get the total length of the unit with 3 x AA to approx. 7" with an optic in place. Without an optic, under 7" shouldn't be a problem. The 26650 model above I think I can get to 4.25" or so comfortably. I think I could make a super short 1 x 14500 unit - I'll look at that too. Once I get them running perfectly, I'd be more than happy to make a production run. These things are gonna be like tanks and shouldn't have anything that makes a failure bottleneck.

Gonna now start twisting (not the dance) to figure out if there are any wear points..

[Harry999]

That is excellent news. I think we will all be keeping an eye on this thread looking for your updates as you progress towards a production model.

Regards

Harry

[TheFraz]

Had a chance to work on the machines a bit today and finished up a CR123 version of the bigger light shown above. Here are a couple pics of the light on super low and on high using one primary 123.




I haven't dressed it up yet or finished it, but new changes to the engine have worked great and it functions better than previous versions. I think I'll have the feel of the light set pretty soon.

Thanks for all the interest guys.

-Fraz

[Harry999]

Seriously it looks great as it currently is as a prototype!

Sent from my GT-I5800 using Tapatalk 2

[Mattaus]

Seriously it looks great as it currently is as a prototype!

+1. Obviously a bit hard to see from photos but it does look good.

[TheFraz]

^ Thanks guys! Here is a pic of the somewhat finished 123 light next to the bigger one with Mack looking on...

[Mattaus]

I like how you've incorporate a sort of brightness level indicator into the rear half of the lights (if those increasingly large notches are what I think they are).

Is there a matching notch on the front end? These look HA anodized as well...you must have access to a serious work shop!

[TheFraz]

I like how you've incorporate a sort of brightness level indicator into the rear half of the lights (if those increasingly large notches are what I think they are).

Is there a matching notch on the front end? These look HA anodized as well...you must have access to a serious work shop!

Good observation - yes, those notches are a sort of indicator of the operation of the light. No matching notch yet...still in the tweaking stage...

I wish I had access to a serious shop! This is garage mechanics....benchtop lathe and mill with some GunKote. And a little baking for curing in the house oven when I can get away with it...

[Mattaus]

is garage mechanics....benchtop lathe and mill with some GunKote. And a little baking for curing in the house oven when I can get away with it...

Well impressive stuff regardless. I've just started learning how to use a lathe and my appreciation for what some members here can create went up infinitely after my first session.

And yes I've been banned from using the house oven for any non-food related baking :-(

[TheFraz]

Thank you...I'm self taught myself. Best way to figure it all out imo is to crank it on and start having success/making mistakes. Well, that and Google.. Threading was especially intimidating at first...only took a few ruined scraps to get it going! One of these days I'm probably gonna be forced into some sort of outdoor oven...

[Mattaus]

Well even though I can make basic parts on the lathe now I still tend to pay people for custom work. Your QTC lights look great and if you ever decide to make and sell a AA based light I'll be all over it - I have 10 brand new Eneloops and no light to use them in (mistake on my part) and the driver less, switchless design of these lights would be perfect...although I prefer single AA and 1.2V won't do much :-/

[TheFraz]

As soon as I get these thing functioning exactly the way I envision, I'll be more than happy to do a production run for those interested. I just want to make something that people will enjoy/appreciate/ find useful. I should have several battery configurations available. Hopefully I can get one working like you are looking for - I'm waiting on new parts to come in now for a beta prototype..

[Mattaus]

As soon as I get these thing functioning exactly the way I envision, I'll be more than happy to do a production run for those interested. I just want to make something that people will enjoy/appreciate/ find useful. I should have several battery configurations available. Hopefully I can get one working like you are looking for - I'm waiting on new parts to come in now for a beta prototype..

Sounds excellent. Less parts to break in these sorts of lights which makes them very good for camping/hiking etc.