500 Lumen - AAA Flashlight (photos) - Work In Progress - Part 2

[cnlson]

Yes! That's even better than the volume knob model.

Also, 5 positions, 72 degrees apart? Do you work for the Pentagon? Are you a star? Gimme five! You devil...

5x72=360 math major in college.
4 levels and off

 

[Cataract]

5x72=360 math major in college.
4 levels and off

25 Gauss 10 millimeters further = more than 24 gauss. Metrologist by profession.

Just wanted to sound smart a**, but I am a metrologist. My comments are based on the idea that hall effect sensors are the best option for durability;

I didn't put the field meter to the ring (...yet, but will have to, now that I've said this). By feel with a metal ruler I can swear the magnet is much much stronger than 25 gauss. By experience (I'll take the ruler to my calibration standard when I have a starting number), you still have more than 24 gauss with a separation of 72 degrees on the torp. I haven't really studied how hall effect sensors are affected by magnetism in different angles (hard info to come by), but a small separation distance might not work since the hardware would likely not be able to tell which sensor is being activated.

GUY: have your tried with much weaker magnets? You might also want to get them from a source that can certify the magnet's strength for a more uniform result.

 

[flashflood]

5x72=360 math major in college.
4 levels and off

Oh, I know. Just couldn't resist: pentagon, star, pentagram (devil), etc.

I should be... Punished.

 

[DBCstm]

There you have it Guy, FlashFlood has volunteered to get the absolute very last Torpedo you ship. He can wait til everyone else gets one for being facetious.

 

[cnlson]

Oh, I know. Just couldn't resist: pentagon, star, pentagram (devil), etc.

I should be... Punished.

Don't say that, it might invite the flashdark mode!

 

[cnlson]

There you have it Guy, FlashFlood has volunteered to get the absolute very last Torpedo you ship. He can wait til everyone else gets one for being facetious.

he waited until AFTER it arrived to say that
http://www.candlepowerforums.com/vb...gress-Part-2&p=4372491&highlight=#post4372491

 

[DBCstm]

I'm so sorry to hear about the recall on X024, what a shame! But you'll get it's replacement, sometime or other...

Thanks for the heads up cnlson, we'll get Uni dispatched right away to pick up that "defective" X024 unit.

 

[fatbrad]

Reporting in X090.

I have been using it exclusively with AAA eneloops. I did a not very precise run time test on level 3 today. It lasted about 4 hours. The cell took a charge of about 750 mAh according to my Maha charger immediately after the test.

I have been carrying mine all the time with using pocket carry. It is holding up very well and it has never accidentally turned on. I have had no issues with the battery running down when the light was off. I have not yet had the battery run out unexpectedly. I have been putting in a fresh battery every 4 or 5 days whether it needed it or not. I have not tried an alkaline cell. I have not tried the short body in the extended position either.

Guy, do you have a cause for the instability of the direction of rotation that increases or decreases the light output? Sorry if you already explained and I missed it. Is the logic losing track of the direction of rotation or is the sensing not reliably sensing the direction of rotation? In my work we use sensors with 3 hall elements to sense the direction. Only two are necessary if the field levels are consistent enough, but having 3 allows for using the change in field strength and for self calibration of the transition thresholds.

I have a couple of thoughts on the final UI design. I really like the originally described UI with one direction of rotation increasing the light output and the other direction decreasing the light output and with lockout achieved by extra rotation in the off direction initiating a requirement for long travel in the on direction to turn on. If the two different rotation levels for off to on transition are not possible, then I would be happy with always requiring a long turn for the off to on transition. If the increasing output direction is always the same, then I don't think there is any need for detentes to be added. I wouldn't mind a physical stop so that rotation was limited to 360 degrees, but I don't think it is required.

The idea of instant access to high from off is somewhat appealing, but for me it is less important than maintaining the simple UI of one direction for more light and the other for less light.

I have had no issues with accidental activation or parasitic drain in the off state. Someone stated the opinion that a physical breaking of the battery feed circuit for lockout was required in order for the light to be acceptable for EDC. I disagree. If some kind of physical disconnect is added to address this desire, I would not want it to be a justification to complicate the interface. I don't want to have to use some secondary switch that would compromise the elegance of twist for on and twist more for more light (with on and more light always being one and only one direction) and would compromise the ease of single-handed use.

 

[Got Lumens?]

Don't say that, it might invite the flashdark mode!

Agreed. Flashdark mode is a prestigious tight closed group, only available by accidental invitation.

Perhaps as Cataract has said, there needs to be a more harmonious effect between the hall sensors and the magnetic ring. With my limited understanding of hall sensors, perhaps some sort of shield between the magnets and external magnetic fields may solve some of the accidential activations and mode changes.

I also think that perfecting the 90 degree, 3 position and off makes more sense at this development stage than decreasing selections by 18 degrees that may add to complexity of the UI as it is now. Being the Torpedo's tight space, I think the addition of more sensors, space provided, could solve many of these concerns.

Example, if the ring direction of turning were to determine advancing and decreasing modes, that would solve some troubles. Another benifit could be how fast the ring is turned, Meaning that if I turn very fast in increasing or decreasing modes, it would advance only one step at a time even if the ring were to be turned 180 degrees. Turning slowly would allow less degrees for mode changes.

Turning one direction for high from Off and the other to Moon sounds very appealing.

GL

 

[the_guy_with_no_name]

Thanks so much for all the posts

Spent most of the weekend digging, shovelling, etc..

The biggest snow storm here in a century though I have to say I enjoyed it but its been somewhat of an emergency about 30km away and onwards so things have been a little on the business as "unusual" this side of the world.

The post office folks are always pleased to see me in the middle of the night.
I think I must be waking them from a trance, where they think morning will never arrive.

Been pushing forward on the Torpedo PCB batch and waiting on one final size check but pending that, looks like the window 5 pcb might be a standard rigid pcb. I adjusted the design and split the board into 3 pieces. Now just waiting to hear back on the connector pins between the boards and if the size is ok, hopefully they can be done before the month is out.

Its still hard to predict the outcome but it will eliminate issues with possible damage, as well as minimize variance in sensor positions which I hope translates to the most stable batch yet. I'm planning on making more than a few spares (roughly 4x the needed number) so even after possible rejects, should have some left.
The assembly to the rigid pcb will be completely automated to maximize precision/consistency.

Whilst thats in progress, I'm working towards the production version too and the deeper I get into the circuitry design (learning more each day, which means more opportunities to meddle, suggest,improve) the more confident I feel that we'll be able to implement all the changes we desire.

The feedback so far has been immensely valuable. Thank you.

Might be another 12hrs or so before I can fully catch up on posts but wanted to jump in for a quick update before that

Tgwnn

 

[DBCstm]

Great to hear the progress, amazing journey for sure.

Sorry to hear about the storm of the century, must be bad for a whole lot of people.

 

[Cataract]

At first I thought you were digging a secondary 42 minute travel hole LOL. Well, it's not funny, I know what shoveling snow like a maniac is like and it's the worst thing to shovel; it doesn't do anything to get you in shape and it feels like it will never end unless you have a heart attack first. I largely preferred shoveling gravel as you do see the progression, and you don't feel like you're huffing and puffing for no reason. Those days are way behind me, though.

Haven't had a chance to do much with my flashdark yet, but hopefully tomorrow. Work has been crazy with follow-ups lately and the pile just seems to grow faster than I can finish just one case. I might be doing some shoveling of my own just to see my desk...

 

[Got Lumens?]

I guess I prefer shoveling gravel also. It usually is not 20 below(-28C) like it was last night.
GL

 

[Cataract]

I guess I prefer shoveling gravel also. It usually is not 20 below(-28C) like it was last night.
GL

And your feet don't get freezing wet. Some people complain that you can always dress warmer in the winter, but we only have so many clothes to take off in the summer. I say when you can only move so much to prevent hypothermia, while a heat stroke is easy to prevent by laying down in the shade with a drink Guy: when's that extreme infra-red light coming out? I thought it was supposed to be in an HF head format... what do you think I got the Cu for? We also need it in toe-pad format that fits inside boots :laughing:

 

[flashflood]

@tgwnn: something I forgot to mention: my precious (X024) doesn't seem to have the parasitic drain issue that other folks have mentioned. I'm using the short body with the new (black) MBI nuke 10250. After three days of light use, the battery is still at 4.12V. Just FYI, in case the lack of problem on this serial number tickles a neuron as to why others are affected and this one is not.

 

[mcbrat]

@tgwnn: something I forgot to mention: my precious (X024) doesn't seem to have the parasitic drain issue that other folks have mentioned. I'm using the short body with the new (black) MBI nuke 10250. After three days of light use, the battery is still at 4.12V. Just FYI, in case the lack of problem on this serial number tickles a neuron as to why others are affected and this one is not.

My x073 does not seem to have the drain issue either, but when I turn it off, I always leave it lined up with a dot. The inconsistencies in UI direction are frustrating when trying to use it one handed. And i dislike having to look at the light to shut it off.

 

[cnlson]

I've noticed some more problems:
1. With 10250 batteries the light usually works on 3rd level only a fraction of second. It works consistently on 3rd level only with fully charged battery, and if the battery is 4.0V or lower, it won't work. Surprisingly, if you are fast enough to scroll to 4th (max) level, it will work for 30sec as it should.

i've noticed this quirk twice. THe first time i swapped batteries and it didn't occur again until it wouldn't maintain the 2nd level and turned out to be down to 2.97v. The second time this occurred I took the battery out and checked it, 3.92v. decided I would check it a bit closer, put it back in and it is still working on level 3 and now it is down to 3.8 with a little more use but maintaining.

I also don't note any parasitic power loss.

guy, quick question, what battery levels are required on the LIONs for the various output levels? for instance, what is the min voltage for stage 4, 3, 2?

 

[the_guy_with_no_name]

one more thing i note. since the nukes are so darn bright i thought it would be fun to EDC it. so on my keychain when the keys are in the ignition, if the road is bumpy the light turns on low. happened 3 times tonight on the way back from Buffalo Wild Wings.

Hi cnlson,

Thanks for noting that good point.
Should be able to eliminate it with much tighter springs.

Guy, that would be greatly appreciated if you can divert it to Texas. Let me know and I'll send you a PayPal.
Husker, if you're not going to use those Efest cells I'll gladly take em off your hands. Shoot me a PM and we'll work out the details. I keep finding more and more ways to use em.

Nice work on all the info Tribal Family. Very good reading and critically pertinent information, ready to give one a go my ownself. (wondering if I can fit an MT-G2 in there...)

Hi Dale,

Landed in Florida, ready for diversion

The beauty of the propeller lockout is that you could also go instantly to off.

If I may get fancy with the propeller lockout idea (like anything has ever stopped me from doing so);
Quarter turn anti-clockwise (with a detent) = lockout, but with mode memory. In other words, when you turn the propeller to the right again, the light comes back on in the last mode it was. I know, very hard to achieve, but check out the REAL fancy part:
3/4 turn anti-clockwise, the propeller pops out 1/8" and becomes a momentary switch. you gotta want to kick me for giving you such tempting yet almost impossible to achieve ideas (like you didn't have enough of your own...) that would give the propeller 100% functionality! (plus, it's like a secret code or an easter egg!!!)


P.S.: I didn't send those flashdark codes... perhaps Uni did or the Unobtanium pill is spreading them through the tunnels, but there is also a possibility the interface funkiness is simulating the code... will definitely try to reproduce it backwards.




The metal parts on cars seem to have an inconvenient tendency to be somewhat magnetic... I never could use a compass inside my cars, perhaps your torp was turned on by proximity to the metal parts -or anti-theft hidden sensor - under the steering wheel while shifting around? Then again, it might just be MY cars that become magnetic from all those abductions...

Hi Cataract,

Thanks for the feedback.
I like the propellor lock-out, not sure how to tackle it just yet though, need to think about it a little.
Magnets....for now, hoping to skip bluetooth and go straight to brainwaves

aaaaand predictably today i could not get it to turn off without lining up the marks. randomly temperamental.
that being the case, although i'm not in favor of a lockout, perhaps it is needed. at least a parking position that cannot turn on (with a detent to be able to put it there by touch.)

i still think 5 postitions, 72 degrees apart, fixed with detents, rotate 1 way for high to low, the other for low to high would be a seriously nice UI. There are times I'd love to start on blindingly bright (what's that noise?) and others the dimmest available (grandkids camping/sleeping in the basement)

any thoughts on a keychain keeper for a spare nuke? although they are bright they seem to run down fairly quickly. something printable on the 3d printer perhaps? Keychain containment

Hi cnlson,
5 positions seems like it would play nicest with the magnets too.
keychain keeper for spare nuke, been in the works for some time but just a metal tube with no electronics....
so the electronics are nearly ready now (functionally perfect, just adjusting layout/size), and I hope that means the keychain keeper is not too far behind.

With constant comment on Ti vs. other metals with better heat transfer, or Ti vs. other metals with less durability (and less beauty) it seems that this copper/titanium alloy could be the perfect answer.

I keep watching your threads, not commenting much because there's so much traffic it's hard to follow, but I'd also think that this alloy could avoid the heavy tarnish and smell issues that some have with copper.

When I first posted about it I half expected you to say you were already working with some and I don't see how you address every single reply here, hold a full time job and make these lights happen.

Hi KD,
Thanks for the feedback.
I need to hunt down some thermal research on CuTi.

>>how you address every single reply here, hold a full time job and make these lights happen
Gotta type like a maniac, sleep like a bird, run like a puma and focus hard

Yes, I'd like to see this kind of UI too.

Thanks agt :thumbsup:

That would be slick.

Hi mcbrat, sure could be

Yes! That's even better than the volume knob model.

Also, 5 positions, 72 degrees apart? Do you work for the Pentagon? Are you a star? Gimme five! You devil...

flashflood,
hahaha.... as long as we don't call it pentax, I'm cool with it

I've been carrying my TorpedoX every day for a couple weeks. I've used it on the job a couple times, but due to the finicky UI, most of my use has been under more casual and less demanding circumstances. I've found that the UI has become slightly more predictable and consistent over time. Some of this is surely due to the fact that although it is finicky, I have picked up on some of its more predictable quirks. I've learned that operating the switch quickly will drive it crazy. If I wait a second before changing settings, it is much more reliable. Also, when it reverses its response to a switch operation, I can now oftentimes slow it down, reverse it again, and then it will settle down to responding properly again.

Here are additional observations in list form:

~ The rotational operation of the switch requires a greater twist for the lowest two positions than it does for the highest two.
~ The rotational operation of the switch is convenient and pleasurable. This design is definitely the best light mechanism I have experienced.
~ The packaging was impressive and I appreciated the attention to detail and polished impression it gave me.
~ One of the batteries remains stuck in the packaging.
~ the short body is offset concentrically from the head.
~ upon arrival, the nuke retained a charge of 3.8 volts.
~ the o-ring would roll out when I assembled the short body (I slowed the assembly process which alleviated the problem).
~ The output is very warm by my eye, much warmer than my HFR-UTT.
~ The output is perceptively less than my UTT, but some of this perception is surely due to the warmer tint.
~ The short body's length feels good in my hand when operating the switch. My first reaction was that I would prefer it to be shorter like my UTT, but after use, I've found this length to be more ergonomic for my hand.
~ I like the sharp tail fins as they make it easier for me to identify the front end without looking.
~ Battery drain during idle is quick. The nukes will go from ~4.15V to ~3.7V in 12 hours without use. It will continue to drain the battery after the auto step down has activated.
~ Battery rattle with eFest 10440.
~ I absolutely love the appearance and aesthetics.

This light is everything I expected for this beta level and I'm looking forward to the production model with a reliable UI. I would opt for a slightly cooler tint if possible. Even with the quirky UI and battery drain issues, it will be a pleasure to carry this light daily for the foreseeable future.

Hi NowIC,

Thanks for posting your feedback (know you've been busy) :thumbsup:

~ the short body is offset concentrically from the head.
What does that mean? larger diameter?

Its seeming very much like there are in fact 2, 3 or even 4 X's.
In checking through some of the reject boards the workshop sent me, I noticed 2 totally different boards (though the layout is mostly the same) and some with slightly different parts (possibly diff spec), which would explain such a broad variety of results.

Za might good news is we're a hair away now of confirming the hard board pcb (size/spec is confirmed) just waiting on the final drawing tomorrow and then its fabrication time.
I'm hopeful that will crush quite a few issues.

However, unless it eliminates all the issues, and as there are still some that may need to be addressed beyond stability, there's a high probability (eg. 101%) that I'll have the circuit redesigned completely.

if anyone needed a small momentary only light, I think a Black Zoom head, black momentary switch, and either Torpedo body would be a slick little package, looking like a tiny MAG.

I just tried it and could not get the short body to fit onto the switch.
Seems like it would be about the same size as the HF-R short body + switch combo.

Tgwnn

p.s. more to follow soon

 

[the_guy_with_no_name]

GUY: have your tried with much weaker magnets? You might also want to get them from a source that can certify the magnet's strength for a more uniform result.

Hi Cataract,

I've been practicing with magnetic brain waves but its still a little hairy
Thanks for mentioning that though.
I don't think its so much a gauss thing, rather the logic.
It would seem to me to fair much better with the 2 sensors position at a right angle on the board, and not go the full circle, but rather stick with the pentagon approach.

Oh, I know. Just couldn't resist: pentagon, star, pentagram (devil), etc.

I should be... Punished.

hehe, no need for punishment flashflood
Everyone who posts here is a STAR in my book!
Just avoid quoting Noah and his ark.

There you have it Guy, FlashFlood has volunteered to get the absolute very last Torpedo you ship. He can wait til everyone else gets one for being facetious.

LOL, its totally fine of course. But the flashdark code is floating out there somewhere

Don't say that, it might invite the flashdark mode!

Ahh... yes, exactly what I was thinking.

he waited until AFTER it arrived to say that
http://www.candlepowerforums.com/vb...gress-Part-2&p=4372491&highlight=#post4372491

Always a much safer option.

I'm so sorry to hear about the recall on X024, what a shame! But you'll get it's replacement, sometime or other...
Thanks for the heads up cnlson, we'll get Uni dispatched right away to pick up that "defective" X024 unit.

Thanks Dale, and I need UNI back here double time to help out when he's done :thumbsup:

Reporting in X090.

I have been using it exclusively with AAA eneloops. I did a not very precise run time test on level 3 today. It lasted about 4 hours. The cell took a charge of about 750 mAh according to my Maha charger immediately after the test.

I have been carrying mine all the time with using pocket carry. It is holding up very well and it has never accidentally turned on. I have had no issues with the battery running down when the light was off. I have not yet had the battery run out unexpectedly. I have been putting in a fresh battery every 4 or 5 days whether it needed it or not. I have not tried an alkaline cell. I have not tried the short body in the extended position either.

Guy, do you have a cause for the instability of the direction of rotation that increases or decreases the light output? Sorry if you already explained and I missed it. Is the logic losing track of the direction of rotation or is the sensing not reliably sensing the direction of rotation? In my work we use sensors with 3 hall elements to sense the direction. Only two are necessary if the field levels are consistent enough, but having 3 allows for using the change in field strength and for self calibration of the transition thresholds.

I have a couple of thoughts on the final UI design. I really like the originally described UI with one direction of rotation increasing the light output and the other direction decreasing the light output and with lockout achieved by extra rotation in the off direction initiating a requirement for long travel in the on direction to turn on. If the two different rotation levels for off to on transition are not possible, then I would be happy with always requiring a long turn for the off to on transition. If the increasing output direction is always the same, then I don't think there is any need for detentes to be added. I wouldn't mind a physical stop so that rotation was limited to 360 degrees, but I don't think it is required.

The idea of instant access to high from off is somewhat appealing, but for me it is less important than maintaining the simple UI of one direction for more light and the other for less light.

I have had no issues with accidental activation or parasitic drain in the off state. Someone stated the opinion that a physical breaking of the battery feed circuit for lockout was required in order for the light to be acceptable for EDC. I disagree. If some kind of physical disconnect is added to address this desire, I would not want it to be a justification to complicate the interface. I don't want to have to use some secondary switch that would compromise the elegance of twist for on and twist more for more light (with on and more light always being one and only one direction) and would compromise the ease of single-handed use.

Hi fatbrad,

Thanks very much for the feedback :twothumbs

Originally, I spec'd 3 Hall sensors but the design opinion was they would not fit in the space.
Self calibration would be phenomenal!
I'll wait to see the result of the forthcoming board, then consider on whether we go the pentagram route or not.
Very pleased to hear you've not been experiencing parasitic drain.

Agreed. Flashdark mode is a prestigious tight closed group, only available by accidental invitation.

Perhaps as Cataract has said, there needs to be a more harmonious effect between the hall sensors and the magnetic ring. With my limited understanding of hall sensors, perhaps some sort of shield between the magnets and external magnetic fields may solve some of the accidential activations and mode changes.

I also think that perfecting the 90 degree, 3 position and off makes more sense at this development stage than decreasing selections by 18 degrees that may add to complexity of the UI as it is now. Being the Torpedo's tight space, I think the addition of more sensors, space provided, could solve many of these concerns.

Example, if the ring direction of turning were to determine advancing and decreasing modes, that would solve some troubles. Another benifit could be how fast the ring is turned, Meaning that if I turn very fast in increasing or decreasing modes, it would advance only one step at a time even if the ring were to be turned 180 degrees. Turning slowly would allow less degrees for mode changes.

Turning one direction for high from Off and the other to Moon sounds very appealing.

GL

Hi GL,

Thanks.
I'm very curious about using some kind of shield between the sensors though in practice, I think the variance should be easy enough to detect. In terms of speed, I think there is some kind of activation/detection threshold timing wise (eg. xx nanoseconds) but it may only be unicorns that are fast enough to slip by it.

Great to hear the progress, amazing journey for sure.

Sorry to hear about the storm of the century, must be bad for a whole lot of people.

I sure enjoyed it but it's been misery for more than a few folks, though most things seem to be back to normal.

At first I thought you were digging a secondary 42 minute travel hole LOL. Well, it's not funny, I know what shoveling snow like a maniac is like and it's the worst thing to shovel; it doesn't do anything to get you in shape and it feels like it will never end unless you have a heart attack first. I largely preferred shoveling gravel as you do see the progression, and you don't feel like you're huffing and puffing for no reason. Those days are way behind me, though.

Haven't had a chance to do much with my flashdark yet, but hopefully tomorrow. Work has been crazy with follow-ups lately and the pile just seems to grow faster than I can finish just one case. I might be doing some shoveling of my own just to see my desk...

I know I'm a nut but I enjoyed all the shovelling too.
I have to shovel my desk every other day or else it gets totally buried.

I guess I prefer shoveling gravel also. It usually is not 20 below(-28C) like it was last night.
GL

Snow is a little less dusty
If the gravel is sandlike, I'll take either

And your feet don't get freezing wet. Some people complain that you can always dress warmer in the winter, but we only have so many clothes to take off in the summer. I say when you can only move so much to prevent hypothermia, while a heat stroke is easy to prevent by laying down in the shade with a drink Guy: when's that extreme infra-red light coming out? I thought it was supposed to be in an HF head format... what do you think I got the Cu for? We also need it in toe-pad format that fits inside boots :laughing:

I started out with multiple layers but was down to a t-shirt within 30 minutes.
Feet and hands, that's another story though....can't have enough good protection.

Are you talking about the HF-W (head/foot warmer)...

@tgwnn: something I forgot to mention: my precious (X024) doesn't seem to have the parasitic drain issue that other folks have mentioned. I'm using the short body with the new (black) MBI nuke 10250. After three days of light use, the battery is still at 4.12V. Just FYI, in case the lack of problem on this serial number tickles a neuron as to why others are affected and this one is not.

Thanks,
appreciate you letting me know that :thumbsup:

My x073 does not seem to have the drain issue either, but when I turn it off, I always leave it lined up with a dot. The inconsistencies in UI direction are frustrating when trying to use it one handed. And i dislike having to look at the light to shut it off.

Of course, I would find them frustrating too and those issues are not s'pposed to be there.
Thanks

i've noticed this quirk twice. THe first time i swapped batteries and it didn't occur again until it wouldn't maintain the 2nd level and turned out to be down to 2.97v. The second time this occurred I took the battery out and checked it, 3.92v. decided I would check it a bit closer, put it back in and it is still working on level 3 and now it is down to 3.8 with a little more use but maintaining.

I also don't note any parasitic power loss.

guy, quick question, what battery levels are required on the LIONs for the various output levels? for instance, what is the min voltage for stage 4, 3, 2?

Thanks for the interesting question.
Honestly I'm not sure yet.

Ideally though, I'd like to see high work >3.V as the minimum.
When the voltage is low, the voltage sag tends to increase when the load is high so I can't know for sure until we test.

Tgwnn

 

[cnlson]

keychain keeper for spare nuke, been in the works for some time but just a metal tube with no electronics....
so the electronics are nearly ready now (functionally perfect, just adjusting layout/size), and I hope that means the keychain keeper is not too far behind.

i was thinking more of something like :
http://www.thingiverse.com/thing:29331
http://www.thingiverse.com/thing:19240

easily printed, light and unobtrusive. a spare payload holder it could even be labeled "spare warhead"