New Headlamp

[CanDo]

Hello everyone,

A new headlamp is being designed by a well-respected foreign company. Your input is wanted.

There is one Cree Q5 providing a medium-sized hotspot, and one that is bare for flood. How do you want the interface to work? Currently, there are two switches, one for each LED. In your work, would you mostly use the flood and throw together - or predominantly flood, and throw only occasionally?

Some options we've discussed:

~Each LED completely independent, and on separate switches.
~Both on high-med-low together, with a second switch providing momentary boost for the throw.
~Both on high-med-low together, with a second switch providing ability to adjust level of throwing beam higher or off.

What are your thoughts? All input is welcome please, even off-topic. When stating what you want, please also mention what your predominant use is, or give some other explanation for your thinking.


Thank you,

CanDo

[angelofwar]

Well, what's the power options? Don't worry about NOT making it a 1XCR123 for higher draw, because most people that would buy it aren't worried about expensive batteries...AA would be better though due to battery availability, but try to make it single cell if at all possible...and yes, it would be nice to have a headlamp with an independent throw and independent flood LED (1-watt of course).

I would like to see one with both switches on the top...but make them predomintly left and predominetly right, and make sure they can't be turned on at the same time.I have 6 Headlamps, and rarely use the colored LED's.

I would DEFINITELY keep the independent switches (being military, I like to have one switch that does this, and one switch that does that...I hate having to cycle through crap...and under pressure I can remember...left flood, right throw...that simple) but would only have the "power" option for the flood LED...forget the "boost" on the throw LED...just make it as powerful as you can, and let us adjust the Flood LED as we deem necessary. Having a Flood LED and a Throw LED on at the same time is disorrienting. Chances are, when I'm wearing a headlamp, I'm concentrating on something (footing in a cave, listening to a CB, etc.) and having to try and mess with too many power levels and different lights, I'll end up hurting myself, because I'm trying to watch where I'm going and adjust the throw LED to Max at the same time (where it should be to begin with). Plus, if I'm going for throw, I'm not trying to be discreet, or worried about flashback anyways. We want the most throw possible with a single flick of the switch...

Basically, a waterproof headlamp with two seperate 1 or 3 watt LED's...one for throw and one for flood, with independent switches, and a low-med-high (in that order) for the flood LED ONLY, would make the perfect headlamp, IMHO.

Here's a lsit of my headlamps, and I have yet to find the perfect one...
1. Rayovac 1-Watt w./ diffuser, red, blue LED
2. Gerber Meridian
3. Rayovac Sportsman white/red LED/Krypton (2ea.)
4. Nightblaster
5. Inova 24/7 w/ headband
6. Foxfury Signature Outdoors

Please let me know if you need clarification or have any questions, but I use my headlamps for my job, Hiking, camping, spelunking, rock climbing, and just about everything else, so I'm more than happy for the input.

[LED_Thrift]

I use headlamps for hiking/camping, xc skiing, mountain biking [not too fast], caving and at home in the attic or under the car etc.

I too think you don't need different levels for the throw LED [high only], only for the flood. A separate switch for each would be great, as you would always have the option of one press for maximum light. You should be able to run both together, as this would simulate most common flashlight beams - a mix of throw and spill - good for many tasks.

I don't think you would be able to get the kind of output / runtime I would like on less than two AAs, probably three. Four AAs would be the max, unless the battery pack is detachable to wear on the belt.

Good luck with your design.
Thrifty

[CanDo]

angleofwar,

Thank you very much for the response. The light will be AA based (optimized for NiMH and/or Li-Ion Rechargeables), but the current plan is two cells with belt-clip power packs available. Why exactly do you prefer a single cell?

Some responses:
~Fear not, no colored LEDs here - we don't see the need.
~Both switches are on top, left and right. This is no fancy-looking light, designed for functionality.
~The throwing chip may have more than one setting, but no more than two, and they will both be bright. The rationality a second setting is that the highest may not be sustainable due to decreased efficiency or heat problems.
~Waterproof? Check.

Thanks very much!

Keep the comments coming everyone!

[CanDo]

EDIT: Double post due to glitch.


LED_Thrift,

Sounds good, thank you. For people like you, who need longer runtime, there will be a 4-6AA belt-pack available. I'm not an engineer, so I'll have to talk more with the team about regulating two separate switches on at the same time.

How does this sound for the throw: One full click turns on high, which is the highest level the chip can be run at with good runtime/efficiency (similar level to the high on 2AA flashlights). Momentary press drives the chip higher, and is not to be used for prolonged periods (for spotting or identifying items beyond normal reach).

[TorchBoy]

You know, when you're the second poster you really don't need to quote the whole original post.

... make sure they can't be turned on at the same time. ... I would DEFINITELY keep the independent switches

Independent switching sounds good. But if you don't want to be able to have them both on at the same time they wouldn't be independent. Which do you want?

Having a Flood LED and a Throw LED on at the same time is disorrienting.

Why do you find that? I would have thought more peripheral light would make most people less disoriented, with or without a bright central spot.

I use headlamps for caving and camping, but make/mod my own, mainly because it's more fun.

[CanDo]

Independent switching sounds good. But if you don't want to be able to have them both on at the same time they wouldn't be independent. Which do you want?

I believe that he means one switch for each side, but that having one side on incapacitates the other. It will be possible to operate both sides at once; one of the questions I'm working out is whether the light will be primarily designed for it or not.

[PhantomPhoton]

I suggested something like this a couple months back. Good to see someone will be doing it.

I'd vote for two independent switches. So once can be run or both can be run at the same time.

Please, please, please NO strobe mode! Worst idea EVER for a headlamp... other than using 3 AAAs or Luxeon 1's in the year 2007.
Why? A headlamp's output is always in your field of view. Disorientation via strobe doesn't happen because a light is blinked in your face... it happens when a bright light source fills your field of vision rapidly. So when a headlamp strobes it can really screw with you. A very bad thing to accidentally bump or cycle through when you're in the dark, walking a slippery narrow path beside a huge waterfall with 50 pounds of gear on your back.

I'm looking for all sorts of outdoor recreational use. Backpacking, night skiing, modest caving, and Search and Rescue are my choice activities that may involve dark.

[TorchBoy]

I believe that he means one switch for each side, ...

Ah, so not being able to accidently turn on both at once, if operating it while wearing gloves, for example.

How does this sound for the throw: One full click turns on high, which is the highest level the chip can be run at with good runtime/efficiency (similar level to the high on 2AA flashlights). Momentary press drives the chip higher, and is not to be used for prolonged periods (for spotting or identifying items beyond normal reach).

Sounds pretty good. That's how I was thinking of using the high mode on my next homemade headlamp.

[Tobias Bossert]

A new headlamp is being designed by a well-respected foreign company. Your input is wanted.

I'm happy to see a professional manufacturer starts this project. I hope this ends up in usefull product, because me and my friends of caving club are looking for usefull headlamps at the moment.

The requirements seem different depending upon application. For caving in large caves I vote for separate switches for beam spotlight and spread working light. Beam spotlight is used short term only to look down into shafts e.g. (no big heatsink necessary and power can be high because no long run time is needed for spotlight). There should be as less spill as possible using spotlight, because this may glare. Consequently working-light should be off at this time. Only one maximum level required for beam.
Please no "multilevel interface", just high and low for working / pause light. No blinking! Working light high enough (at least 50 lm real overall output) and more than 6 hours runtime (needs much more than 2AA). Battery pack either at the rear of helmet or worn separately (prefered).

Note http://www.candlepowerforums.com/vb/...11#post2296711

[greenLED]

Some options we've discussed:

~Each LED completely independent, and on separate switches.
~Both on high-med-low together, with a second switch providing momentary boost for the throw.
~Both on high-med-low together, with a second switch providing ability to adjust level of throwing beam higher or off.

Two emitters, 3 levels, 2 switches...

If you have 2 independent switches, each operating one of the emitters, how would the user know which level each emitter is on? How would the headlamp be turned off... cycling both switches, pressing both switches, pressing a certain one and holding it for a given time, pressing-holding either one?

I don't have the answer to any of those, but...

When stating what you want, please also mention what your predominant use is, or give some other explanation for your thinking.

If I may ask, what is yourdesign intent for this headlamp? How do you see it being used? IMO, it'd be easier if you had a solid plan in mind rather than relying on what CPFers want. You know how it goes when somebody asks "what keychain light should I buy?"... people even suggest HID's.

[nzgunnie]

Seperate switches, NO stupid strobe mode!

I'd like to see it kept simple. Certainly no clicking endlessly through different modes. I think the throw should be as bright as it can be only, and the flood should have a high and a low. And by low I mean really quite low (5-10 lumens?).

AA batteries would be preferred.

My use would be working on helicopters in the dark, in fairly low threat environment (white light acceptable/required), working in the back of a truck loading ammo cans and cleaning machine guns, and then in my tent for reading and rummaging around in my pack.

[half-watt]

1. two emitters - one flood and one spot

2. two switches with both LEDs being capable of being powered at the same time if the user/wearer so desires

3. LONG burntime is required since it may be used for backpacking. so, a) sufficient battery power to allow this, and b) a low enough low (5-10lm???) to burn a long time. few can hike any demanding trail at 5-10lm, though a clear non-technical path is doable at this light level, but 5-10lm is sufficient for in camp task/proximity lighting IME (in my experience), or even in most attics (indoors, even though "non-reflective" compared to a mirror, there are a lot of surfaces that reflect light back to the eye; not so outdoors - light gets "swallowed up").

4. multi-level on the throw/spot LED is required as well as HI-Flood may not allow picking out blazes 30' ahead, but HI-Spot may be overkill with only a ~1h burntime. i find in some cases 15lm smooth reflector SPOT is enough to hike a non-demanding trail by, but 25-30lm is needed on some trails. having another additional 100lm THROW o.p. (output) in reserve is comforting, so a Q5 is really needed for throw. other than SAR (search and rescue), i don't see a need for MEGA-THROW and MEGA-LUMEN output. IME, in winter snow, less light is needed as snow reflects light quite well. can't speak to mountaineering however, as i've never done mountaineering.

5. prefer LOW-MED-HI order for at least the FLOOD, but maybe to make it less confusing to some users, both need to operate the same way. i'd really like to see LO-MED-HI for both emitters though.

6. also, TIMED switching is a MUST, IMO. what i mean is something similar to Petzl and PTec headlamps. one can cycle through the o.p. modes if button presses are performed withing 0.5s of the prev. button press. however, if more time elapses, then the next button press turns the light OFF without having to cycle through any remaining modes to get to OFF. being forced to cycle through o.p. levels/modes to get to OFF is a poor design, IMO, and irks many users of lights. even better, is the PT Apex timed OFF - must press and hold for a full second or two from any mode, by either switch, to turn the light OFF. or a Fenix-style full press on/off and half-press mode/level change (though with gloves on this becomes more difficult - headlamps are often used by backpackers when wearing gloves due to the cold). so, i'd say duplicate the PT Apex UI (two switches, including TIMING for OFF), but change the order to LO-MED-HI (nothing worse than being blasted by HIGH light levels in a dark forest - yeah,...i could close my eyes if i'm the one doing the switching, but when a trekking mate does it without alerting me, it's rather unpleasant, so LOW first, please). IMO, three o.p. levels are really required, with MED being bright enough (~30lm) for most backpacking uses. this allows the longest possible burntime. HI o.p. level is left for RESERVE uses in special circumstances. Your Petzl Myo-XP BOOST is a good idea, but probably unnecessary, IMO, if MED = a true ~30lm "TORCH", and HI=a true 100+lm from the "TORCH" vs. the emitter.


lastly, what i'd really like to see (i suggested this to PTec over two years ago, but they never responded - before Petzl brought out a modular system and mentioned this in detail at that time also on Backpackinglight.com Forums) is an interchangeable headlamp system. what do i mean?

design your electronics to handle a wide range of Vin. then, sell separate battery packs (yeah,...this would mean that the battery boxes/packs are probably remoted either in the back of the head, or inside a jacket/jacket-pocket or inside of the backpack; however, a front-mounted modular system could be designed, though this might cause the "head" of the light to stick out a bit further than otherwise).

having a modular approach utilizing separate "heads" and battery-boxes, allows interchanging headband and further remote packs, also it will allow different battery types (3xAA, 4xAA, 2xCR123, 2x2xCR123 [use diodes to prevent one side from attempting to charge the other side if one cell is weak], 3xCR123A, 2x3xCR123A 3xC, 4xC 4xC, 4xD, even 9V "transistor" battery, etc.). it will also provide support for Li-ion cells (though these are far less used by avid backpackers due to availability in "Trail Towns" and the need for charging prior to use - not many backpackers carry an AC charger - though for car campers, a DC charger would be fine).

you can sell the different battery boxes as accessories. this will also allow you to very easily bring out new "heads" too. the different "heads" can be easily swapped in by unplugging the cable from the currently mounted head, removing the current "head" from the headstrap and replacing it with another head for a different purpose, e.g. super-long burntime with a lowered powered emitter or a PT Corona-like array of Nichia DS 5mm LEDs, or a "head" with both WHITE and RED LEDs for those that require such for their application (Astronomy buffs, for instance). it's difficult to make a single headlamp be all-things-to-all-people. this modular approach is the closest one can come without having to purchase multiple complete headlamps.

not sure of how professional marketing would view this approach. obviously, selling entire separate headlamps would make more money, but many can only afford one or two headlamps. they need to save for months to justify the purchase of even a $75 headlamp. such individuals, would find it far easier to justify a $30 "head", or a $20 battery box EVERY MONTH until they had collected *ALL* of the available ACCESSORIES - perhaps even those that they don't primarily intend to use. it is possible, that greater $$ might be generate in sales by this approach than by the more traditional non-modular approach.

furthermore, "Jumbo-Packs" could be sold with multiple heads and battery boxes for those who want to spend $200-$300 or more in one purchase.

cavers are, perhaps, more familiar with "a la carte" headlamps. that is, buy a "head"/light-generating unit, buy an attachment mechanism (headstrap - cloth or rubber, or helmet mounting bracket), and finally buy some batteries to connect to the (often common trailer-plug) "head". so, this modular (aka "a la carte") approach to headlamps is no brand spankin' new idea. what would be new (and perhaps patentable by y'all) is a modular system that can accept a wide range of Vin as described above.

my two shekels.

[Garnett]

Hiya. Fairly new and I think fairly esoteric use of headlamps, so my opinions might not be the most average:

My use is camping abroad.

I would like:

AA or AAA power. I know AAAs aren't popular, so AA would be my choice. This is because recharging batteries is often not an option, and replacements should be cheap and easy to find.

A additional red LED. Again I know these aren't always popular, but I find a red LED is great for providing just enough light to see my way without disturbing other people or ruining night vision

[CanDo]

Thank you very much, everyone for the responses!

Phantom Photon,

There is no strobe mode - this is no tactical, blind the imaginary enemy light. We are considering an emergency mode, but that would operate on an independent switch, and in all likelihood will not happen.


Tobias,
The 2xAA is worn at the back of the head, but a 4-6 (most likely 6) AA belt pack will also be available.

Green LED,
One switch for flood - one click low, one medium, one high, one off (timed, so that if you are working in one mode for more than two seconds, it goes immediately to OFF rather than changing modes. One switch for throw - on/off, momentary boost. It really shouldn't be too difficult to figure out once it's in your hands.

We have a very solid plan as far as the construction and design, and a strong framework for the electronics. I'm sorry, but I can't go into more detail than I already am in responding to people's inquiries. I am not a "put your suggestion in, and get your headlamp out" machine. I am only trying to gather feedback and am simultaneously looking for those few and far between great ideas. It seems pretty frequent that a light will roll out, it will be liked, but there will be some movement for change - often enough, the manufacturer delivers. Wouldn't it be nice to get this is as right as possible from the start? CPFers can be a very esoteric bunch, and we keep that in mind designing a light for the masses, but we certainly aren't going to write off their input - who knows more than them about lights?

half-watt,
A lot of good information in your post, most of which we are already working on.

Garnett,

Sorry, but no red LEDs here. There will be a very low, low mode, however, or else you'd have to just use a key chain light.

[ltiu]

Waterproof!

Use AA batteries!

Multiple light levels and I want it Fxcken bright at it's brightest level (greater than 100 lumens)!

No more than U$120.

[mountainpenguin]

not in the least bit interested by aa.
Lithium and a decent (6 hours +) on high
solid built (like a sten)
2 switches would be great
not sure a bare led would be so great. Ideally i would like ~ 60% in a circle round my feet and the rest illuminating around.
Basically a sten with 2 switches, one very wide asymmetric optic / reflector and one for throw.

[half-watt]

One switch for flood - one click low, one medium, one high, one off (timed, so that if you are working in one mode for more than two seconds, it goes immediately to OFF rather than changing modes. One switch for throw - on/off, momentary boost.

your flood operation is perfect, IMO. however, your SPOT/Throw emitter modes leaves a little to be desired, IMO. Why do i make such a bold statement?

ok, it's just my opinion after decades of trekking the forest trails, but here's why...


even the Zebralight H50 with its FLOOD Cree-Q5 at 66lm is not always sufficient for spotting low contrast, faded blazes on rocks and tree trunks out 30+ feet. And even if it is, many will want >2.3h of burntime. Hence, the need for a SPOT. Even if you're gonna' provide >100lm of FLOOD and i can spot blazes 40-50 feet away, it's still gonna' hurt burntime.

therefore, i want a SPOT/throw emitter with other than a similar short burntime. i very rarely need 100+ lumens of THROW output in the forest (other than SAR and maybe mountaineering). i would still suggest keeping a HIGH of >100+ lumens, but we need a lower SPOT/Throw of, let's say 25-30 lumens (out the FRONT, not at the emitter) to have both a long burntime and be able to sufficiently pick out ALL blazes far enough ahead. i'd also say keep a LOW spot/throw output level for times when 5-10 (or even 15) lumens is sufficient for hiking a non-demanding path.

all things being equal, you'll be able to use a lower total light output with the attendant longer burntime if you use a spot beam versus a flood beam. i'm sure that i'm not giving a new revelation here; y'all already know this, but maybe aren't as familiar with how many backpackers will use your headlamp. backpackers, as opposed to campers, love LONG BURNTIMES - it means that fewer, or no spare cells, have to be packed and carried (space and weight requirements).

not every backpacker wants a headlamp solely for in camp task/proximity lighting. i'll stick with a Photon Freedom Microlight, Petzl ZipkaPlus, or PTec Quad for those purposes. longer burntime with some SPOT/Throw output less than MAX is what, i predict, many avid backpackers will want in order to be able to perform nighttime navigation for 6-8 hours, or more without having to change batteries.

also, the lighter in weight the better, so simply adding more batteries (2x4AA cells, or larger batteries, e.g. 4D) is *NOT* the answer. we have to "hump" these cells and possibly spares for a week over rough terrain with the rest of our gear until we reach the next "trail town" where we can discard the used cells properly and purchase new ones. we like carrying less weight whenever possible.

sure, you could use less than MAX flood output for that purpose (maybe???), but you're going to have to have a greater lumen output to accomplish the same level of visibility. hence, a shorter burntime is the result.

flood output is really better for task/proximity lighting in camp and perhaps also for "filling in" when on the move (it would help for those afraid of the dark too).

the spot/throw beam pattern shouldn't be too tight/small however, otherwise, "chicken walking", as i term it, is going to be required, i.e. one's head bobbing about like a chicken walking trying to place too small a hotspot on far away trunks and rocks trying to spot a blaze marking a turn in an unfamiliar trail.

this is not just an esoteric CPF-er talkin' here; i have decades of trekkin' experience and used to do quite a bit of nighttime trekking and orienteering.

i'd suggest that you go over to www.backpackinglight.com and field suggestions there. a headlamp will be used primarily (i'm guessing) by backpackers, mountaineers, campers, mountain bikers, trail runners, kayakers, etc. - you'll find all of these folks alive and kickin over there. having participated over there for a 2+ years, i can tell you that you'll have many individuals with decades of trekking and mountaineering experience from all over the world responding with suggestions. i'm guessing, based upon knowing them, many will have comments similar to my own, and even some better ones than i've tried to communicate to y'all. the folks there are perhaps equal in education and intelligence to many of the best minds here on CPF, and also equally polite as the best here.


my two shekels.

[mt_vertcaver]

My two cents:

Primary use - Caving
Other use - camping, night hiking, car repair, general light


2 switches
Level switching similar to PT Apex
Ability to switch both spot and flood on at same time
High only on spot (don't need multiple levels here)

AA batteries

Minimum 7 hour general run time (primarily High-Flood with intermittent Spot)

Waterproof
Durable

Price under $100

I would NOT want a belt pack.


Basically, you need to make a better light than my Apex for me to buy it. Hope this helps and good luck!

[half-watt]

High only on spot (don't need multiple levels here)

by this do you mean just for caving where a flood of light goes a long way (except perhaps in large caverns), hence, MED. output SPOT is unnecessary since MAX spot would be required in large caverns? please clarify, if you don't mind.

i'd agree with your statement for caving, but not for backpacking. a flood output just needs to be too high a lumen value as compared to a spot output to accomplish the same purposes when on the move in the dark. the need for a greater lumen output in flood versus spot obviously results in a lesser burntime for the same battery power.

out in the forest, or worse in a field, light just gets swallowed up as there are not as many reflective surfaces to reflect the light back to the eye. i've exited some trails into large fields and need to pick up the trail where it enters the forest on the other side of the field - often NOT directly across from where i exited the forest. flood is next to useless here, except for wandering around hoping to find where to pick up the trail. of course, less than MAX spot may not help here either *IF* the field is too large. however, i have a better chance of spotting it with a medium powered spot than a max powered flood.

low/lower power flood is great for in camp task/proximity lighting purposes, however.

now if it's solely a caving headlamp that is being produced (perhaps i missed that point by the OP???), then i'll keep silent - IMO, you're absolutely right in your suggestions for caving purposes.

[hayhay]

This looks absolutely awesome!!! I also agree with self-watt's ideas of having a medium (and even low) level for the spot beam. This way, you could have a cross between a zebralight for the flood, and a handheld torch for more throw, all in one package! Might I add also, if you are pretty set on having the "boost" option for the spot beam, you could have a separate button for it (similar to the tikka xp) that you could access from any level, and still keep a low-med-hi button separately to access the spot beam on the side. If you wanted the sos function too, you could use that "boost" or "extra function" button (could be put in the middle of the flood and spot buttons) and use it for the sos feature for the flood beam. So in conclusion, keep the low-med-high option for the flood AND spot beams and possibly have a 3rd button in the middle for spot "boost" and flood "sos" (though not needed but I think a good idea) Just my two cents

[mdocod]

lots of neat ideas here. I think I'll go ahead and weigh in here in agreement with much of what has been said with a few thoughts added about the power supply:

Separate switches for separate LEDs in this design is a must. They need to be easy to locate, with good tactile feel, but positioned such that they aren't likely to be activated/damaged by bumping your head against a rock. Consider that headlamps are often used with gloves on, thick gloves should not make it impossible to operate the switches. (I often use headlamps while out in the snow working on things, like say, snow-blowing the driveway.)

With decent heat-sinking a ~3W mode is definitely possible and should be available. As far as the number of modes available, everyone has their own preference of course, Personally I like 3 modes for lights with "1W" high setting and 4 modes for those with "3+W" high settings.

For 4 mode regulation I like the following very approximate distribution:
~800mA(~200 lumen? ~3200mW), ~250mA(~75 lumen? ~800mW), ~75mA(~25 lumen? ~200mW), ~20mA(~7 lumen? ~50mW)

The idea with this type of layout is that it makes calculating runtimes "in the head" to get a rough idea is much easier. Each mode uses approximately 4X the wattage more or less than the mode next to it. (The numbers in the example above are rough interpretations of the cree specifications charts that will certainly be different on different Vin Bins and such so would have to be adjusted accordingly.)... So if you are using say, a 6AA eneloop pack, You can assume about 2 hours runtime with both LEDs on high. Then you can just multiply out for a rough estimate of runtime on lower modes. 1 LED on high, 4 hours, 16 hours on med-high, 64 hours on med-low, 256 hours on low. (assuming the regulator is reasonably efficient on all modes, a good PWM should be above 90% approaching 99% in most circumstances as I understand.) Calculating for running 2 LEDs on the same mode you simply halve the estimated runtime.

Now I'd like to point out my thoughts on power sources... Making a light that can run on BOTH a 2xAA source on the head and a larger (assuming higher voltage) pack externally can be difficult because you need to provide both voltage boosting and bucking capabilities to the circuit., IMO a good headlamp is an efficient headlamp, using input voltages ABOVE the Vin of the LED and bucking them down is the most efficient way to drive an LED as I understand. IMO the lowest "ideal" voltage source for driving LEDs is 4 NIMH/ALK/NICD cells. Even then some regulators will drop out of regulation on high before the cells are depleted because many PWM regulators need ~0.5-1V above the Vout in order to stay in regulation. Anyways, most people serious about a serious performing headlamp are going to be ok with a 4AA head pack, but keep in mind that a compact 2xCR123 would do pretty well and be more compact (providing around an hour of output on 2xhigh). IMO though, for headlamps in this power class, larger power sources are a must for any sort of long-term use on higher levels. Consider 4xC, 6xAA, 4x18650 (protected cells only)....

Now... others have mentioned that if you can't make "high" a selectable continuous output, don't bother, don't mess around with "turbo" modes that are temporary. "Turbo" modes are cheesy and not practical in the field. Figure out what the highest practical mode is that you can dissipate heat for on your design and make that the high, even if it's only 350mA per LED. As other have said, no strobes or SOSs, strobes and SOS modes will simply get in the way and be a nuisance.

[LED_Thrift]

What mdocod said about having the power levels all four times [current wise] apart is a very good idea. I also second his idea about not having a temporary turbo mode and just using the highest setting that you can with regard to heat disipation.

[angelofwar]

angleofwar,

Thank you very much for the response. The light will be AA based (optimized for NiMH and/or Li-Ion Rechargeables), but the current plan is two cells with belt-clip power packs available. Why exactly do you prefer a single cell?

Some responses:
~Fear not, no colored LEDs here - we don't see the need.
~Both switches are on top, left and right. This is no fancy-looking light, designed for functionality.
~The throwing chip may have more than one setting, but no more than two, and they will both be bright. The rationality a second setting is that the highest may not be sustainable due to decreased efficiency or heat problems.
~Waterproof? Check.

Thanks very much!

Keep the comments coming everyone!

The single cell...It's just easier...you just have to switch them out more often...either one's fine, as long as the battery pack is solid, and low profile (ditto on not having the "belt clip BTW) but I like it best when you said "functionality"...A black box on your head with two lights and two switches...done...forget all the twirly-gig crap. And the two settings on the "throw" LED wouldn't be bad...3 is when they start getting annoying...but as you explained it in this thread, I would definitely buy one (or two...or three...hey, this is CPF, right?)

[mdocod]

Another thought just came to mind:
(hopefully this hasn't been mentioned already)...

For the spot beam, use a lens/optical device that produces ONLY a spot beam and nothing more (minimal or no spill). These are ideal because they can generate massive throw from relatively small sizes. the idea being here that one can actually choose not to have any flood at all if that is what one wants, there are situations where trying to spot something off in the distance can be made much easier if you have NO flood around you, the excess light in the flood from common reflector beams can cause your eyes to adjust "down" so that things off in the distance are harder to see. Being able to really "hone in" on the perfect spot beam and flood beam combined would really be NICE!

Ordinarily I HATE these types of focusing optics on flashlights because I prefer the spill-beam to be there for 90% of tasks, but in a headlamp where you could control both the spot and spill being able to isolate the spot beam would be amazing!

[f22shift]

make a zebralight (1aa) form but with a push button on/off, half click low/high modes. with ssc p4 and some kind of optic for med throw.

[PhantomPhoton]

I'll jump back in and put in my thoughts after thinking this over for the day.

2 switches is very good. Being able to run both at the same time is an absolute must. So may other headlamps fail because of this. They have (after I've modded them) good throw from the primary, and good flood from 5mm LEDs but I can't turn both on at the same time. So I like where things are going with this light.

My opinion is there need only be 2 settings on each LED. Low and High. Though I could take a very low for ~5 lumens as mdocod suggested.
From the example of only low and high you have 8 different possible modes.
Low flood
Low throw
Low flood and throw
High flood
High throw
Low flood and High throw
Low throw and High flood
High flood and High throw

And the beauty of this setup with 2 switches is that you don't have to click 8 times to cycle modes.

I also agree that a turbo mode is more of a gimmick than an actual useful function. I don't like the Petzl LED headlamps with this function.
Keep it simple. No flashes/sos is fine by me, as is no additional 5mm colored LEDs... even though I personally want both features in a headlamp. Leaving the turbo out simplifies things more.

Let the thrower throw as hard as it can. Its just going to throw with less runtime if we're flooding hard too. And (again) I agree with mdocod that using a very tight beam is useful. In rain, snow, fog - the more flood we get, the less visibility we actually have. This is extremely amplified by a headlamp being that the light source is so near our eyes. Eliminating backscatter would be great.

I'll have to make sure I have a lot of money saved up for a couple of these headlamps this spring.

[Daekar]

Another thought just came to mind:
(hopefully this hasn't been mentioned already)...

For the spot beam, use a lens/optical device that produces ONLY a spot beam and nothing more (minimal or no spill). These are ideal because they can generate massive throw from relatively small sizes. the idea being here that one can actually choose not to have any flood at all if that is what one wants, there are situations where trying to spot something off in the distance can be made much easier if you have NO flood around you, the excess light in the flood from common reflector beams can cause your eyes to adjust "down" so that things off in the distance are harder to see. Being able to really "hone in" on the perfect spot beam and flood beam combined would really be NICE!

Ordinarily I HATE these types of focusing optics on flashlights because I prefer the spill-beam to be there for 90% of tasks, but in a headlamp where you could control both the spot and spill being able to isolate the spot beam would be amazing!

This is an EXCELLENT point, one that I hope you take to heart. If you have a spill-less and flood-less optic, not only does that mean that your pupils won't shrink in response to light close up, you can also eliminate the flood/spill to help with light reflection in poor visibility conditions and get the same throw for less current to the emitter, and thus longer runtime. This setup makes perfect sense - because you always have the option of turning on the flood beam if you want flood! Plus, there's always the efficiency bonus of under-driving the emitters...

If I could design a headlamp myself, it would be a combination of my PT Apex and my Zebralight H50: Tough. Waterproof. Approximately the physical user-interface of the Apex, with off-low-med-high-off settings for both throw and flood (more on UI below). Two Cree emitters, one with a spill-less optic as described by mdocod just above, one with a total-flood emitter like the Zebralight with one difference, the current Zebralight is a 120 degree circle. I would make the output elliptical: keep the 120 degree horizontal angle and decrease the vertical angle to 75-90 degrees or so. This should keep your peripheral vision good but prevent quite so much light from going into the sky, and result in slightly higher lux readings for any given drive level (more brightness/runtime).

Batteries: I have chosen 2 battery options to base my light collection on: AA and 18650. AAs because they're common, small, have decent energy density, and are available in various chemistry options - I use Eneloops in literally every AA light I have except my ROP, but would use Energizer lithiums for backpacking. I chose 18650s because of their LSD, energy density, and size... unless you're putting out a lot of power, you only need one to run the light. I'm hoping to see a light like the one you're describing available in 2AA and 1x18650, both with the battery on the forehead, with the possible option of a 6xAA or 8xAA and 3x18650(3p) or 4x18650(2s2p) belt pack.

Brightness: You've probably figured out by now that the Apex and the H50 are the lights to beat. The Apex is versatile but crude in comparison to the simply elegant execution of the H50, particularly in one main way: the light levels. The light levels in the H50 seem to take into account the logarithmic way the eye perceives light, and so the three levels (three are DEFINITELY needed when the highest gets only 2 hours of runtime) are arranged such that there is a marked difference between each one. Low is quite low, for those times when you don't need much light - medium is brighter, for those times when you need more than just a few lumens but still don't need much, and high is pretty darn bright! The nature of the beam prevents it from reaching out too far into the night, but at the distances its intended to be used everything is evenly lit-up like the light of day. I hope your engineers purchase/use an H50 when considering drive levels and beam qualities. The brightness of the throw emitter will be slightly harder to pin down, but I feel that it too should have three settings - that way the flood and throw can be used together based on the light and runtime needs of the task at hand. Sometimes flood by itself isn't enough, you need just a little throw - but not much, so you put flood on medium and throw on medium. Maybe you want to use throw primarily, and just have the flood on low to keep you from tripping on your own feet or walking into a spiderweb, rock, or hole. Maybe you want as much as you can get of both and put both on high - or maybe you want the runtime offered by low with the versatility offered by both flood and throw on low. In order to make the throw emitter worth having it needs to be good enough to negate the need for a second light for throw.

Buttons: Three buttons, one for flood, one for throw, and one for "both." Position them so they can't be mistaken for each other - flood right-bottom, throw left-bottom, and "both" in the middle-top. All operate low-med-high-low-med-high-low-etc. Hold any button to turn off the associated beam regardless of current power level. Like the Apex, put some kind of easily identifiable tactile form on each button to make it identifiable by touch. This would mean that if you wanted both beams on medium, from off you press the "both" button twice. If you wanted flood on low and throw on high, you press either flood once and throw three times, or "both" once and throw twice. If you wanted flood on high and throw on low, you press either throw once and flood three times, or "both" once and flood twice.

Beam-alignment: It occurs to me that one of the essential elements that makes the H50 great is that it can be rotated in its mounting to direct that flood beam so it's placed just as you like it. The Apex also has a hinge which allows the same function. This new light would be much less user-friendly if it didn't have something to allow for the same kind of adjustment. The question is, are the two beams going to be independently adjustable? If they are sensibly aligned relative to each-other during the design/testing process, it may be that independently-swiveling beams isn't necessary - but it would be VERY nice. Some people may want to adjust the flood beam to illuminate their feet as they walk with the throw beam higher for longer-range objects, but some others may want the throw-beam centered in the flood beam (cavers?). As small a detail as it might seem, I think it might be the difference between a good headlamp and a great one.

Hope my input was helpful...

EDIT: Was just reading through to make sure I didn't miss anything and I did. Please please please take mdocod's advice and dispense with "turbo" modes, strobes, or any other such foolishness. Those are for torches, not headlamps. Even if that weren't the case, I imagine it would be worth eliminating the turbo mode just to avoid customer complaints about overheating or damaged lamps...

Now... others have mentioned that if you can't make "high" a selectable continuous output, don't bother, don't mess around with "turbo" modes that are temporary. "Turbo" modes are cheesy and not practical in the field. Figure out what the highest practical mode is that you can dissipate heat for on your design and make that the high, even if it's only 350mA per LED. As other have said, no strobes or SOSs, strobes and SOS modes will simply get in the way and be a nuisance.

[greenLED]

Green LED,
One switch for flood - one click low, one medium, one high, one off (timed, so that if you are working in one mode for more than two seconds, it goes immediately to OFF rather than changing modes. One switch for throw - on/off, momentary boost. It really shouldn't be too difficult to figure out once it's in your hands.

We have a very solid plan as far as the construction and design, and a strong framework for the electronics. I'm sorry, but I can't go into more detail than I already am in responding to people's inquiries. I am not a "put your suggestion in, and get your headlamp out" machine. I am only trying to gather feedback and am simultaneously looking for those few and far between great ideas. It seems pretty frequent that a light will roll out, it will be liked, but there will be some movement for change - often enough, the manufacturer delivers. Wouldn't it be nice to get this is as right as possible from the start? CPFers can be a very esoteric bunch, and we keep that in mind designing a light for the masses, but we certainly aren't going to write off their input - who knows more than them about lights?

Excellent! I like that approach much better. For a minute I thought you were asking for our "wish list", and you know the kitchen sink will be on it.

FWIW, I pretty much agree with half-watt and what his uses are and what he's saying. Along those lines, I'm not sure I like the default 2 second auto-off either. I can see circumstances where I'd want both beams on.

Not sure how to balance that, though. Maybe program a "warning blink" for the secondary mode (whichever gets turned on second)? Input from the user (click) would restart the timer. I'll leave it at that 'cuz it's bound to get complicated and it sounds like you have already thought about some of these things.

[NoFair]

+1 with what Daeker says.

The small battery pack on the head would be for short time use and as a back up.

If you use good connectors (plenty in the RC community) one could use several different packs to wear on the body/in a pocket or where the user would prefer.

2 switches and the option to have both lamps on at the same time would be best

Thanks for asking for input.

Sverre