Variable Brightness & KISS: Why not more U2 Type Selector Rings?

I am a fan of variable brightness lights, but admit I get frustrated at times with all the different and overly complicated UIs---twist back and forth, multi-click, multi-tap, remember how many seconds before it "locks", dodging SOS/strobe, etc. The simplest, fastest, most user friendly UI I ever experienced was the U2's selector ring. How nice to simply and quickly twist the dial to exactly where you want it.

My question is, aside from patent issues, why do more lights not have a simple manual UI, such as the U2's, for changing levels?

Perhaps cost and durability/reliability issues?

Hall effect sensors are quite strong units and so are the magnets the light should NOT be introduced to tempuratures that could damage the magnet. I find that the U2 UI is very very good (I want mine back :'() Fenix has those L2S's that have 2 levels and a tai lswitch using a twsity bezel like twisty U2 ring only I think (guessing) it adds a resistor to the circuit when on low.

cost and size, and maybe reliability as well... i bet this type of switch isn't cheap and it probably takes some doing to do a switch like this well and do it right. i'm sure SF's wasn't charging an arm and a leg for the U2 when it first came out for the hell of it.

...actually on second thought....

I agree.

I would like to see continuously variable output flashlights with a user interface like this:

A tail cap clickie for on/off (that's all it does).

Twist the head one way for more output, the other way for less (like turning a volume knob on a stereo).

No more "stepped" output: variable all the way from really dim to full output. Really, really simple.

AdamW said:

No more "stepped" output: variable all the way from really dim to full output. Really, really simple.

Click to expand...

Except designing and implementing such beasts (infinite variable output, or selector rings) is no trivial task!

Almost by definition variable brightness precludes KISS, at least from design and implementation points of view. From a user stand point, selector rings are awesome!

greenLED said:

Except designing and implementing such beasts (infinite variable output, or selector rings) is no trivial task!

Almost by definition variable brightness precludes KISS, at least from design and implementation points of view. From a user stand point, selector rings are awesome!

Click to expand...

The only triviall way to implement continuously variable dimming would be with a variable resistor, wired in series with one set of leads from a two-level switch, either full, or dimmed (with user selectable resistance). Efficient dimming however using a current regulator, or even PWM is much more difficult by comparison, but that's what you'd need to do if you really want to save on battery life.

AFAustin said:

My question is, aside from patent issues, why do more lights not have a simple manual UI, such as the U2's, for changing levels?

Click to expand...

It's not easy to design - and you can see from the prices of variable output lights like the Gladius ($250ish) and the Titan ($500.00)

There was a CPF variable output light - but the light levels/steps were not well designed. It's available out there somewhere, and it's not too expensive.

PWM dimming is less expensive to do, but some users notice the flickering at low light levels.

I'm working on a variable level design, and I have the variable section done, but there are the protection circuits and other stuff still to do.

Thank you, gentlemen, for your comments. And good luck, LightBright, on your design----hope we'll be the first to get a peek.

I hope I expressed my original question correctly---my understanding of "variable continuous brightness" is that it increases or decreases output so gradually that "stages", as such, are imperceptible (such as with a dimmer switch for a ceiling fixture at home).

While I understand that VCB is the Holy Grail, I was really only expressing a wish for more "user simple" multi-stage switch designs, such as the U2's (which I believe has 6 distinct levels).

Thanks again for your comments.

Don't selector rings make it a two-handed operation? Some people want selectability in a one-handed operation.

Giving it a bit of thought (not a lot, mind you) ISTM a handy UI would be a tail clicky (non-reverse so you can have tactical-style momentary on) and a selector ring that would select one of three modes: 1. Full-bore, 2. Clicky steps through three or so lower light levels, 3. Strobe and SOS that clicky steps through. For modes 2 & 3: Light should remember where it was last and return to that. Quick stroke of the clicky with the light on moves through selections. Hold clicky in for X seconds or more to turn on. Hold clicky in for Y seconds or more to turn off. (Hold-down time for off can be [much?] shorter than to turn on, for obvious reason.)

If you really wanted to get fancy: A 4th selection that allowed the clicky to step though full-bore and whatever was last used in modes 2 & 3 . Momenary and start-up in full-bore.

I use the selector just fine with one hand.

Variable brightness is not KISS, imo - for 2 major reasons:
1) Makes it way harder to guess how long battery will live
2) "why" do you really need it? In a logical sense, it makes sense that more control over the brightness ("I can set it at ANY brightness at all") would be good, but in practical (KISS) terms, there's just no need for it. 2 discreet brightness levels is usually all anyone practically ever needs. Even on my U2, 98% of the time, it's either on level 1 or level 6 - rarely anywhere in between.

I agree, there needs to be some major head-scratching & drawing-board action regarding UI. Once I got a U2, I got spoiled

I feel qualified to jump in here with a comment as I am a machinist and also a lover of variable light output.

First of, variable output is a must have as the newer powerful emitters will demand it. In most EDC applications one will need to be able to lower the output and why just have one low level when one could have many.

The mechanical option chosen by surefire for their new Titan is bound to be quite intricate and costly to produce and not modder friendly.

One viable alternative are the excellent drivers made by member Georges80 which incorporate one of the simplest and most intuitive Ui out there.

His drivers feature a simple push button on the head for all functions, and a Ui that can be user set for different sequences and 5 or 8 step light dimming.

While these drivers are for sale directly from his website, to get them in completed lights, one has to buy them used as the Lion Heart, Lion Cub and Chameleon.

More details on these superb drivers can be had from George's website

Website

or from my website below in signature.

I dunno why there aren't more selector rings like that on the U2. I love my U2. I like being able to set the output before I turn it on. I don't find it particularly difficult to operate one handle. And, I prefer the constant current driver in the U2 over any PWM dimmed light I've seen.

I love my U2.

I have a design in process that uses an U2 style selector ring, for the progress check this post: Pineapple Head

Making a continuosly dimming design its possible, but implementing it using a U2 style ring is no easy task, mostly because the hall sensors need to see the magnetic field perpendicular to its face.

There is a new breed of hall sensors that read the position of a magnetic field rotating over it, but for using these, you would need to rethink completelly the mechanical part


Pablo

I prefer the detented one that the Kroma uses. I like the idea that I'm gonna get SOME light as soon as the button is pressed, better IMHO in high stress situations or for use by people who don't have HDS training.

2xTrinity said:

The only triviall way to implement continuously variable dimming would be with a variable resistor, wired in series with one set of leads from a two-level switch, either full, or dimmed (with user selectable resistance). Efficient dimming however using a current regulator, or even PWM is much more difficult by comparison, but that's what you'd need to do if you really want to save on battery life.

Click to expand...

Forgive me here folks, but the electronics for continuously-variable (or fine-stepped) brightness are almost trivial.

The mechanics for me are not trivial, but I suspect there are plenty of people on the forum who know one end of an O-ring frm the other.

Steve

ok Steve- go ahead and make a board for the modders for a reasonable price. No PWM, 90% + efficiency Buck/Boost 3.0Vin min variable DC drive 1ma to 1Amp for Luxeons and Crees, single LED, 0.65" Dia board, simple user interface.

Bandgap said:

Forgive me here folks, but the electronics for continuously-variable (or fine-stepped) brightness are almost trivial.

The mechanics for me are not trivial, but I suspect there are plenty of people on the forum who know one end of an O-ring frm the other.

Steve

Click to expand...

Almost agree, but the mechanics of this setup are still evading me


Pablo

For any of you who might be familiar with the CentraLED, check out these renderings of our prototype flashlight:

http://bpond.smugmug.com/gallery/2024704/1/103777449

This flashlight uses the same lamphead as the CentraLED, which has a flood beam pattern providing smooth, even illumination of an area. Note the knurled ring at the base of the lamphead. Twist that ring for continuously-variable output.

The picture is obviously just a CAD rendering, but we had working prototypes on public display at our major automotive trade show (SEMA) in November '06. We then showed production-ready models at SHOT '07. A few CPF'rs came by our booth at SHOT and they seemed suitably impressed.

I would say that the mechanical engineering required to pull this off far outweighed the electrical engineering. The design uses a potentiometer, whose axis of rotation needs to be common with the flashlight's central axis. Once a pot is chosen, that defines where the rest of the PCB is located and creates all sorts of design constraints. Now you've got to get battery power in to the PCB, and LED power out. One set of those connections is spinning with the knurled ring and the other set is stationary with the flashlight body. It's not trivial to do this.

Electrically, I'll be the first to admit that yes, it uses PWM. We put a lot of effort into finding an optimum PWM frequency to minimize the strobing effect, and I think the results are pretty darn good. The pot is a component of a very simple timer circuit which fires the enable pin on the driver IC. It's not rocket science; pretty much every driver IC datasheet teaches you how to do this. Electrical complexity with this design is quite low and therefore reliability is high. We looked first at doing current control instead of PWM, but the problem was the lack of availability of an appropriate potentiometer. Continuously variable current control requires the pot to provide the feedback signal directly to the IC, and to achieve maximum brightness at one end of the scale, the pot resistance value had to be very nearly zero. Pot's just aren't built that way.

We are using a twisty tailcap with a tactical momentary, and we are establishing a small fixed current on the low output end so that no matter where the ring happens to be positioned, you'll get something when the light is turned on. It works out to about 6 lumens on the low end and 80 lumens on the high end. Power source is 2xCR123A. Initial production will all be black HA-III, but we are looking at offering a camo model later. Output adjustment is easily done one-handed, with the body of the flashlight gripped in the palm, and thumb and forefinger twisting the ring.

Anglepoise said:

One viable alternative are the excellent drivers made by member Georges80 which incorporate one of the simplest and most intuitive Ui out there.

His drivers feature a simple push button on the head for all functions, and a Ui that can be user set for different sequences and 5 or 8 step light dimming.

While these drivers are for sale directly from his website, to get them in completed lights, one has to buy them used as the Lion Heart, Lion Cub and Chameleon.

More details on these superb drivers can be had from George's website

Website

or from my website below in signature.

Click to expand...

George also makes the Fatman, which is dimmable with a potentiometer.