Wednesday, December 30, 2009

Flashlight Insanity


You press, twist, or slide a switch and light comes out. How complicated can this be? If you head over to Candlepower Forums, you can begin to get an idea. In this article I'll run through a brief introduction of flashlight madness, culminating in the Christmas present I got myself, the LiteFlux LF2XT.

Flashlight Fascination

Much like cars, guns, toy trains and so forth, flashlights fascinate many people (mostly geeky guys, it seems.) I'm not sure where the fascination comes from, but in my case it goes back as far as I can remember. Perhaps there's something primal about having the power of light in your grasp? As fascinations go, though, flashlights tend to be a rather practical outlet of perfectionist energy.

Burn a Bulb or Love the LED?

Flashlights used to have simple incandescent bulbs, like those Edison came up with -- a metal filament glowing in a protective gas. Gradual improvements followed; halogen, xenon, increasingly high pressures allowing for brighter and whiter light, ways to protect the filament from breaking due to bumps against the light etc. Basically, the more you paid, the fancier of a bulb you got.

What has lately changed the game are two developments -- you can now get High Intensity Discharge lights, just like the headlights in luxury cars, in a form factor that qualifies as a flashlight. These are expensive and relatively large, and I shan't discuss them. The second new technology is the Light Emitting Diode, LED for short. While LEDs and LEDs in portable lighting aren't new, the advent of 1, 3 and 5 watt Luxeon, Cree, etc. LEDs has totally changed the playing field -- you can get more light out of an LED than you could out of a high-end bulb just a few years back -- and it will run several times longer and never burns out. LEDs can also produce whiter light, and feature instant on and instant off. They can also be dimmed without affecting the color temperature (for practical purposes.)

Fancy Flashlights

So, what can we do to overengineer a flashlight? I used to be happy with my Underwater Kinetics lights -- they had nice bright, white light, were waterproof, and reliable. Then my roommate at the time got me a SureFire Z2, and it went downhill from there. You can see my Z2 in the picture above; it's the topmost, biggest flashlight. The SureFire lights are exorbitantly expensive, but they have to be held and tried to be believed. The light is smooth, without rings or lopsided patterns; the light is bright, and the construction is literally bomb-proof (as per a special operations soldier I spoke to.) I would not hesitate to drive over my Z2 and expect it to keep working. I can drive nails with the thing.

To put the brightness in perspective, a good, traditional 2D flashlight (Maglite) produces less than 37 lumens. Out of the box the Z2 produced 60 lumens, and I upgraded the lamp to produce 120 lumens. A flashlight the fraction of the size of a Maglite produces over three times as much light!

As mentioned, you can replace the lamp module, and there are a large number of accessories available; color filters, battery cases, replacement switches etc. You can in fact upgrade your old light with a purpose built LED module, to keep with the times. But it wasn't until I discovered Candlepower Forums that I realized that there is competition. Even so, SureFires are a cornerstone of high-end flashlights, and a "standard" of sorts -- you can buy third party components that are interchangeable with the Surefire components and vice versa. In fact, there are tens, if not hundreds of third-party lamp modules you can buy for your Surefire, as well as sapphire glass, anti-reflective coated glass, crenelated bezels, and pretty much anything you can possibly think of.

Fantastic Features

Aside from other LED lights of equal brightness to the Surefires, the competition offers features. Since the LEDs are driven by relatively fancy electronics, adding some more logic didn't take much of a leap. Consequently, you end up with lights that have several power levels, strobe modes etc. They come in all kinds of sizes, with various kinds of user interfaces; some you twist, some you press, etc. The variety is bewildering. The lights also differ between their beam pattern -- how wide is the angle of light. A small angle gives you a pencil beam that will light up objects far away, but doesn't give much coverage. A large angle gives you a flood of light, covering a lot of area, but won't reach as far.

The middle light in the picture above is a 1 CR123 Nitecore SmartPD EX10. It's as bright as my stock Surefire was in about a quarter of the size, and has variable brightness. This is what has been in my pocket for a while, for work and walks at night, but will now be replaced by the LF2XT, which I'll cover in a bit. Other brands worth looking at for nifty little lights are 4Sevens, Fenix, Streamlight and Novatac to mention but a few.

Batteries Included

Another aspect you might notice in regards to "tactical" or otherwise fancy flashlights is their power source. Instead of AA or D cells, they typically use CR123 lithium cells. They're ludicrously expensive if bought locally, but can be had at about $1.50 a piece mail order. Like AA lithium batteries, they pack a lot of power for their size, they are fairly impervious to temperatures and they have a shelf life of a decade or more and don't go bad even if partially used. More recently people have started to use rechargeable batteries either in the CR123 form factor, or in multiples and fractions thereof, for example 1.5 CR123 lengths or 2 CR123 lengths. These rechargeables are Lithium-Ion, much like modern laptop batteries and require completely different chargers than your normal rechargeable AAs. They aren't mainstream because the voltage you get out of a rechargeable version of a CR123 is significantly different from the voltage of a regular battery -- but since the fancy flashlights use advanced regulating electronics anyhow, they don't really care what voltage you feed them. In fact, you can have one, two and three cell flashlights share the same bulb assembly; it just converts the voltage automatically.

The Liteflux LF2XT

What makes my little AAA powered flashlight (on the bottom in the picture above, smallest of the three) so insane is not its brightness. It's pretty bright for a tiny AAA light, but not enough to really stand out. No, what makes this light complete lunacy is the user interface. The flashlight has one binary button. That's it. Yet, with just one button to enter commands, a clever engineer from Taiwan has managed to create a state machine interfaces that consumes three pages in flow chart format.

For starters, the light has a "simple" mode and a "complex" mode, with normal or tactical submodes under each. In the complex mode, the light has five selectable output profiles. By default these were 50% brightness, 15% brightness, 1% brightness, 50% beacon and 15% SOS morse mode. But this, of course is horribly restrictive -- so, the user can select how many output profiles they want to activate, and they can change each of these profiles to suit their taste. You can pick between a regular "always on" light, a strobe, a beacon (short blinks separated by relatively long periods of off) and SOS. But of course, you also need to be able to adjust the brightness of each mode. And, while we're at it, you can customize the frequency of the strobe and beacon modes. The light also will measure battery voltage, and indicate this with a number of blinks equal to the voltage (blink, pause, blink, blink, blink being 1.3 volts, for example.) It lets you also query its current brightness level using the same logic. Further customization can be done by determining whether the light turns off automatically after three minutes, whether it remembers the profile it was when you turned it off, whether it should shut down at low battery voltages to prevent you from discharging a rechargeable battery too far, and a few other things. And lest this all is too simple, there are shortcuts for random strobe and full power.

How does this work in practice? For example, to turn on the light, I tap the button. While the light is on, if I press and hold, it overrides whatever output profile the light is in and turns on full power for as long as I hold the button. If I tap once, then hold, it goes into strobe mode for as long as I keep the button depressed.

To program, when the light is on, I tap the button three times. From there, one tap increases brightness of the current profile, two reduces brightness, triple tap exits, triple-tap plus hold exits and saves new settings. Eight taps and a hold will toggle whether the light has an automatic timeout or not, and indicates its current state with either a double or single blink. Other functions are accessed and changed with similar logic. The flow chart is pretty much a necessity.

...needless to mention there are now custom third-party firmware updates available for people to whom this is too restrictive.