# best bang for the buck DIY LED project



## coombs (Jun 22, 2005)

Hello gentlemen. I'm a rookie light builder looking for some wisdom, experience, and guidance. I've been quite impressed with the creativity and practicality of the DIY lights here. Particularly, I'm impressed with DIY Dinotte style and DIY done cheap because of their simple and effective designs. So... I'd like to build a light of my own. I don't have $300 to spend on a light, but I'd like the same performance from a DIY if possible. Complete build ideas are what I'm looking for. I'm especially interested in the pros and cons of different drivers, seoul vs. cree emitters, and round vs. square lenses. And again, if a $3.19 driver will work in the place of a $30 bflex, I'd prefer $3.19.  I think I can put together a couple DIY dinottes, but I have questions in my mind about whether it's better to use a seoul or a cree. And if I use a cree, can I find round lenses in both spot and flood patterns (one for the helmet and 1 or 2 for the bars)? And then, can I get away with using a cheap driver from DX or kaidomain? Or maybe it's just better to use square lenses, and I need to start over completely. Like I said, I'm a rookie. Thanks in advance for your help.


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## Guest (Apr 25, 2008)

I prefer Seoul P4 U bin as its a little easier to get optics such as the ones from L2. As for square lenses the ones with the wider beam simply have a frosting to the front and you lose some light unlike the round L2 ones that are made with a wider beam but still clear. As for drivers I'm afraid I have to put reliability at the forefront as I ride in some dodgy forests in the middle of London and don't want to be left in the dark so I always use a Bflex or a buckpuck. If however you choose to use Cree you may as well try and get hold of the new R2 bin that is brighter than the Seoul P4, that is at least until the Seoul P4 W bin arrives. Just my thoughts, hope that helps a little bit. Edit, forgot to say you can get a buckpuck for about $14.


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## Ochils11 (Mar 22, 2008)

Hi,

You'll find round optics and olders for CREE and Seoul at http://www.led-tech.de/de/High-Power-Zubehoer/Carclo-Optiken-c_106_107.html

Holders for Cree can be found at the bottom of the page, you will need to modify the holders if your emitters are mounted on stars.

The holders won't fit into 25mm OD aluminium tubing unless the wall thickness is less than 1mm, found out the hard way and had to machine the tubing out a little to make them fit.

They deliver quite quickly and don't overcharge on P&P

I'm new to light building and have bought a few drivers from Dealextreme and Kaidomain to try along with a couple of Seoul P7 C bin 900 lumen emitters, still waiting on delivery of the drivers.

Currently running the CREE XR-E Q5's from 4 double AA's at 700ma without any problems.

Regards,


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## znomit (Dec 27, 2007)

Dweeby the L2 optics are available for cree too. Yes they are fantastic, though quite large. Im currently using polymer optics because they are so small and make a nice compact light head. For a narrow beam these cree optics from Kai are very good and cheap.

The SSC P4 Ubin has very wide binning. See here. At 350mA its quoted as 91 - 118lm. People tend to quote the 118 number for brightness rather than the 91 number.  
A cree R2 is only a little brighter than this on paper at 114-122lm. I assume the SSCs have been getting brighter over time as they move towards V bin, exactly where they are in the 91-118lm range who knows, they aren't putting out V bins yet so they are probably somewhat short of the 118 target. If the LEDs you buy have been sitting at the supplier for a while you will be closer to 91. For the small cost difference I would certainly go with R2s or Q5s.

Coombs there are a lot of different DIY setups, what you go with will depend on your access to tools, what materials you can scrounge up and how much money you want to sink into it. Spend a while reading the DIY threads here and check out CPF too.

The optics have a big influence over the usability of the light. If you are unsure what you want the L2 are a good choice as you can swap out the front diffuser to change the beam. A good start would be a triple with 1 wide 1 narrow and whatever you are happy with for the third.

For drivers, you do seem to get what you pay for. The bflex is a very smart design and makes the ride experience a lot nicer. Do you really want to have to cycle through an SOS mode when you just want a little less light(or worse, a little more!)? The extra 27$ gives you programmable light levels, low battery warning, temperature sensing and easy control over 5 light levels.


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## yetibetty (Dec 24, 2007)

znomit, those L2 optics for the Cree use frosting on anything wider than the spot, unlike the L2 optics for the ssc that are clear, so they would probably take away the little bit of extra light you have gained by using a cree.

coombs, cheap drivers are meant for torches and I just wouldn't trust them on a 3 hour bike ride in the pitch black of night. If you just want simply diming then a buckpuck from ledsuply is a good cost effective way to get a well proven driver.


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## joebreez (Sep 10, 2005)

coombs, I'm currently building my sixth light.
I have done the "Achesalot" design twice, relatively simple and something you don't need a machine shop to make.
I do like the il2mb design slightly better though, but only if 2 LED's are enough for you.
It's a roomier design that is slightly simpler than the "Achesalot" design. You can get the square optics from Ledil and use an "oval" lens which gives good spread but concentrated in a band and then a "soft spot" for some good throw down range.
With the 2 LED's you'll end up with just slightly over 400lm considering optic loss.
As for the driver's, spend the money and get either the 3023 ($17)from LED supply or contact TaskLed and get the bFlex($30)-which is more expensive but more flexible.
If you're worried about heat, either drive the light @700ma (340lm)or drive @1000ma(450lm) and buy some computer heat sinks like a "Thermaltake" video card version.Mount them to the outside where the heat path is best.
The hardest part I think is making a decent mounting system, look up Trailtec handlebar mounts on Batteryspace.com.
For a helmet mount you may want to check out some of the past posts for ideas.
Good luck, take your time(you have all summer) and use quality parts and think out the design. There's nothing worse than being done but not happy with the end result.
Check out the link http://forums.mtbr.com/showthread.php?t=392719

Eric S


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## coombs (Jun 22, 2005)

Thanks for the replies. So what I've learned so far is that I need to use a good driver. What's the difference between a 3021 and a 3023? Can they be adjusted to dim at say 700-800mA and then at 1A?
Secondly, I think I hear you fellas saying that a Q5 and especially an R2 would produce more lumens than a P4. However, I also think that the lens options are better for the P4's, especially round flood-type lenses. So I'm still undecided there.
I was thinking maybe to try two DIY dinottes with wide lenses on the bars and one with a narrow beam on the helmet. Now I'm entertaining a 2-LED light like il2mb's on the bars and a DIY dinotte for the helmet.
I freely admit that I have no machining tools and no skill, so a simple housing is better than some CNC magic.
Thanks again for your help.


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## joebreez (Sep 10, 2005)

3023 is the new number for the older 3021- the difference is that the 3023 is prewired.
You can still get a 3021 but you need to get a harness separately.
I don't remember if they sell them with an adjustment, but if there is it is only adjustable internally. Set it and forget it.
As for the Bin number's a P4 lens will fit a Q5 or any other Cree the same style.
Spend the extra money and get at least a Q4-5. R2's are hard to find and are back ordered on many sites.
Remember, bars usually are more "flood" and helmet are more "Spot" normally.

Eric S


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## UpRocks (Jun 24, 2004)

coombs said:


> I was thinking maybe to try two DIY dinottes with wide lenses on the bars and one with a narrow beam on the helmet. Now I'm entertaining a 2-LED light like il2mb's on the bars and a DIY dinotte for the helmet.


I would think either would be adequate. I am very pleased with the DIY Dinotte's I am running. I've built 4, but rarely get to ride with more than one (turns out the kids love night riding).

I have found that with some flood on the bars, a single R2 @ 800mA with a spot optic is plenty of light on the head for me.


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## tamen00 (Mar 10, 2004)

If you go with the P4 and the ledil optics, I would try the spot and medium lenses. I found the wide lens was way too wide for mtb use, however the spot and the medium together work excellent. FWIW I have build a bunch of the DIY Dinotte style lights with the cheapo Deal Extreme drivers (4 drivers for like $6.44) and have had good luck with them (800 mah... but thye have been running closer to 1000 mah current from the driver) 

If you want a light you turn on, no options for dimming, blinking, etc., I think those drivers work pretty well. As far as long term reliability? Not sure on that one. I live in AZ, so I ride at night a lot!!! One of the lights has been going for over 4 months now with several 4 hour+night rides a week on it, and it has been working fine.


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## coombs (Jun 22, 2005)

Tamen, thanks for the info. I guess a $6.44 experiment wouldn't hurt.
I've been looking for R2's and the only place I can find them is Cutter. Is that the only source?
I also saw this puppy, but I can't find any optics for it. That would make a serious DIY dinotte.
I'm still not decided on the quality of square vs. round optics. If you have opinions or experience in comparing the two, I'd be grateful! Thanks again.


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## tamen00 (Mar 10, 2004)

Yeah, that would make a sweet Dinotte style light, however i do not think there are any optics that would work for it yet.

What kind of batteries are you going to be running with your lights? I am running the cheapo drivers with 7.2v lithium packs and getting a little over 3.7 hours runtime on each light with a 240 mah battery. One thing that is a bummer with the protected battery packs and the cheapo drivers is once the battery drops below the max discharge voltage, the protection circuit kicks in and everything goes pitch black (I found this out the hard way)

I ride a lot at night and was worried about the reliabilty of my first few lights, so I made each one its own system (lighthead, switch, battery) so if one failed, the others would still work. I have been riding for a couple of years with just an old HID and no backup... that probably was not smart but I was never stranded. 

The next one that I am building is going to be my "Nice" light for 24 hour races. It is going to be set up exactly like the nightrider Dual X2... two lightheads connected to one battery, with one switch, each mounted on the bar. I will be running the 4800 mah battery (3.5 hours runtime guessing) and each light will have its own driver. I will also run one of the lights on my helmet with a 2400 mah battery. So, for a solo 24 hour race, I will need 4 of each battery, and should be good to go for the entire night without having to worry about recharging (super sweeeeet!!)

Also, I am just using the Seoul P4 leds. I have one spot and one medium on the handlebar, and a spot for the helmet. This has worked the best for me and lights up the trail enough that in my last race, I was able to turn the same laptimes as during the day (I was on a team for that one and was just experimenting with my "prototypes".

All told, with all of the parts, each lighthead cost $18, the batteries cost $15 for the 2400 mah, and $25 for the 4800 mah ones, and a charger was 20 bucks. So for roughly $200 I have a very light (each lighthead and battery weighs 175 grams) setup that burns for 12+hours, and is about the same "brightness" of my old niterider HID... I am very happy and P97 is the man for coming up with this setup!!


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## SkUG (Feb 19, 2008)

coombs said:


> Tamen, thanks for the info. I guess a $6.44 experiment wouldn't hurt.
> I've been looking for R2's and the only place I can find them is Cutter. Is that the only source?
> I also saw this puppy, but I can't find any optics for it. That would make a serious DIY dinotte.
> I'm still not decided on the quality of square vs. round optics. If you have opinions or experience in comparing the two, I'd be grateful! Thanks again.


cheaper here (takes bloody ages to turn up too!)


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## Guest (Apr 27, 2008)

Lumitonix has a good range of Leds if you don't mind going German.


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## znomit (Dec 27, 2007)

coombs said:


> I also saw this puppy, but I can't find any optics for it. That would make a serious DIY dinotte.


Yeah, looks impressive. 
Tri rebel torch here.


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## fre3ud (Apr 29, 2008)

*Minimalist zen*

Direct driving a CREE R2 off three AA NiMH using a low profile 9° Fraen Collimator seems to work fine. It draws about 680mA initially, dropping to about 500mA at two hours. It doesn't have quite the same total light as my 35W 10° halogen but runs for nearly 3 hours off only a few grams of batteries vs having 1½ kg of SLA in the back pack for the halogen, plus no cost or weight for the driver and case. The light head is just a short piece of 25mm od 1.6mm wall thickness ally tube - sold in 2400mm lengths as closet rail. Had to slightly ream one end to press fit the taper sided collimator in but no glue required. Back of star PCB is flush with other end of tube; star is thermal glued to thin pice of alloy which is both headsink and cilp to hold on helmet. Non-riding vision of 40-60m depending on humidity as haze cuts back visibility as get fuzzy brightness in beam path. When riding at 15-20kph in singletrack can see about 20m ahead and this seems fine. I'm using the warm white as although it has less lumens than the cool white it gives me better "read" of the terrain as a night light when in trees etc. For road riding the cool white is better as absolute light level seems to be nest for the speeds there - descending unlit country roads at 40+ kph needs all the light you can get!


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## Guest (Jun 22, 2008)

Why don't you really splash out and have a pair


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## WeLight (Aug 12, 2007)

R2 Warm White ? Must be a different code as R2 is only avail in Cool White ?


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## fre3ud (Apr 29, 2008)

*Another born every day*

Thanks for your feedback, Mark. I had been following the threads on the cpf site regarding how to tell whether any given DX or other non-Cutter sourced (in)conveniently unmarked power leds were "real". I see Lumileds make theirs a bit fancy - but I guess anything can be copied.

Bought the star from Jaycar.







and http://www.jaycar.co.nz/productView.asp?ID=ZD0444
I was looking in the latest hardcopy catalogue at the time - having just ridden 15km there on a Sunday afternoon to buy a DC connector - and saw the w/w R2 so bought one to see what the colour was like compared to c/w one.
When I got home I was skeptical as I couldn't find any data on the CREE website for the R2 bins, so I kept the pack label and receipt. Maybe I will go and have a talk with them and ask for the batch code for these! Jaycar sell both a warm white and a cool white at the claimed R2 level, but don't have one of each sourced from them to compare.

Its definitely a physical match for the CREE item. Using a current contolled power supply I can drive it to 1050mA (requires Vf of about 4.05V) and while it gets warm, it doesn't look like cooking so probably isn't a lesser beast that would die at around 800mA.

But if CREE didn't make it, what is it?

I've been meaning to build a small cheap n dirty lux meter to help solve these ongoing issues. There are a few PIC based designs out there. Maybe will do that one evening when its too wet to ride.

Phil


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## znomit (Dec 27, 2007)

fre3ud said:


> Using a current contolled power supply I can drive it to 1050mA (requires Vf of about 4.05V)


Something funny going on.
My R2s from cutter have always been around 3.6V :eekster:

35$ for a single LED???? :eekster: :eekster:

The do have some interesting little drivers though... :yesnod:


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## WeLight (Aug 12, 2007)

fre3ud said:


> Thanks for your feedback, Mark. I had been following the threads on the cpf site regarding how to tell whether any given DX or other non-Cutter sourced (in)conveniently unmarked power leds were "real". I see Lumileds make theirs a bit fancy - but I guess anything can be copied.
> 
> Bought the star from Jaycar.
> View attachment 370709
> ...


Hi Phil
Let me clear a little air around this issue in point form
- We supply Jaycar with all their leds and we mount them on star board for them
- We supply them with 4 types XRC in Cold and Warm and XRE in Cold and Warm
- absolute best bin in Warm White is P4 flux, so the label is incorrect and I will call Jaycar to day to get them to change the description
- Warm whites from Cree are spec'd at 700mA drive current max(XRC at 500ma)

I hope this clears up the confusion


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## sean newell (Aug 15, 2006)

I was fascinated by your simple build Phil & immediately rushed off & copied it - worked a treat. So I got to thinking - why not 2,3 or 4 in series direct drive? I use radio control 7.2v Nimh for my lights [ 2 in series = 14.4 v], so I ran 2 R2s in series directly off a 7.2v - worked fine ; 700mA & looked just as bright as from a driver . I'll try 4 soon. So - am I going to stuff these LEDs ? Are drivers just an expensive on/off switch ? Obviously there is no multi-mode, & maybe as the battery runs down the LEDs will go out earlier. Am I missing something else obvious?


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## znomit (Dec 27, 2007)

sean newell said:


> I was fascinated by your simple build Phil & immediately rushed off & copied it - worked a treat. So I got to thinking - why not 2,3 or 4 in series direct drive? I use radio control 7.2v Nimh for my lights [ 2 in series = 14.4 v], so I ran 2 R2s in series directly off a 7.2v - worked fine ; 700mA & looked just as bright as from a driver . I'll try 4 soon. So - am I going to stuff these LEDs ? Are drivers just an expensive on/off switch ? Obviously there is no multi-mode, & maybe as the battery runs down the LEDs will go out earlier. Am I missing something else obvious?


Yeah it can work though its usually frowned upon. :nono:

You need to be careful about max battery voltage, so you don't cook the LEDs, and minimum voltage so your lights don't go out. In general a few more volts and a series resistor is a good idea. Batteries with a flat discharge curve are good too.
3 LEDs off 14.4v with a resistor to limit current and a pot to vary brightness would work well (I made a similar double running 8AAs). The aussie AYUP lights just use a resistor.

Drivers aren't on/off. They feed the correct current regardless of battery voltage(within limits). 
DX drivers are a few bucks and taskled are around 30. The price and the quality are both an order of magnitude different.


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## fre3ud (Apr 29, 2008)

Yes, this direct drive is not conventional but this thread is about best bang for buck so extras like buck, boost, or boost/buck don't come into it - or switches either.

As above, overvoltage can destroy the led - see the steepness of the Vf vs If curve here 
http://www.cree.com/products/pdf/XLamp7090XR-E.pdf
but the destruction is mainly because of local heat build-up and it the led is on a decent area of metal it can take quite a lot of current.
Most of the improvements from the early Luxeons to the recent CREE and SSC led are to do with reduction in the internal electrical resistance to produce less heat (or at least produce it evenly across the led profile to avoid hot-spots) and in the package thermal resistance to transfer away the heat from the junctions quickly.

NiMH and Li-ion both have quite flat discharge curves with steep knees at the end so even using a boost drive the lamp will go dark quite abruptly at the voltage drop. I don't think this will affect the argument as much as znomit implies. Just carry a spare battery pack - as you would anyway if you were venturing far after dark.

As to losing led life - hey take away 90% of the expected 50,000 hour life (to 70% illuminance) and you are left with only 5,000 hours - that's 208 days constant running!! Assume you use it only 4 hours *every *day - its gonna last 3 or 4 years. There will be newer and brighter and more efficient chips to move to well before then.
In the halogen days we happily over-volted our lamps - I still quite cheerfully push mine and if I blow one every month or two - they're all cheap these days.

My real driver is based around a microchip 12C675 with a check on the voltage every 60 secs or so and a little beeper plus a light pulse to warn of end of battery immanence. But that costs a few dollars more and is, again, not where this thread is going.


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## sean newell (Aug 15, 2006)

I like the idea of 3 LEDs off 14.4v . Can you help me work out the resistor? 3 LEDs by 3.6v =10.8v , subtract from the battery = 3.6 volt , divide by the total current [ ~ 1.05 amp ] , about 3.5 ohms ?! That's not much of a resistor , I must be wrong....


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## znomit (Dec 27, 2007)

sean newell said:


> I like the idea of 3 LEDs off 14.4v . Can you help me work out the resistor? 3 LEDs by 3.6v =10.8v , subtract from the battery = 3.6 volt , divide by the total current [ ~ 1.05 amp ] , about 3.5 ohms ?! That's not much of a resistor , I must be wrong....


yeah, thats right, but fresh NiMh cells are 1.4V each meaning you've got 16.8V and 1.7A :madmax: 
And when discharged they are 1.1V so you get 650mA :skep:

And the batteries droop under load but how much? :crazy:

Best to be conservative and measure your setup.
Resistors are cheap so grab a range from 6.7ohms down to 3.5 (5W). Hook em up to fresh cells and LEDs and see what you get.... either ammeter or measure the voltage across the resistor. After that is in put a 10ohm pot in series to give good dimming, you'll be surprised how seldom you need 700lm! Other solution is wire a resistor across a switch to give high/low.


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## fre3ud (Apr 29, 2008)

If you are going to go to all that trouble you might as well do the right thing as use a basic buck smps board like:
http://www.cutter.com.au/proddetail.php?prod=cut762


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## glowinthedark (Jul 8, 2008)

fre3ud said:


> Direct driving a warm-white R2 off three AA NiMH using a low profile 9° Fraen Collimator seems to work fine. It draws about 680mA initially, dropping to about 500mA at two hours. It doesn't have quite the same total light as my 35W 10° halogen but runs for nearly 3 hours off only a few grams of batteries vs having 1½ kg of SLA in the back pack for the halogen, plus no cost or weight for the driver and case. The light head is just a short piece of 25mm od 1.6mm wall thickness ally tube - sold in 2400mm lengths as closet rail.


This sounds like a really nice cheap easy solution to getting into LED bike lighting. My homebrew SLA halogen setup recently bit the dust (battery and/or charger rooted). I already have a NiMH Charger + batteries for all the electronic gizmos.

I reckon I can start with something like you describe and always upgrade to all manner of fancy drivers if the mood takes me.

I am thinking of these parts from cutter:

Cree XR-E Optic Part Number XLSL-7090-247 : $4.22 Inc. GST

(they have the fraen optic but without a holder and the light efficiency of the other optic is better)

Cree XR-E R2 Flux (WH Tint) Cold White mounted on 20mm round MCPCB : $11.89 Inc. GST

So for $16.11 (inc GST) I have a very nice bright light.

Add in a switched 4xAA box from Jaycar for $2.25 and it's all sweet (obviously I'd have to short one of the AA slots in the box).

The holder for the CREE optic is 23.5mm at the front, so I might have to do some shaving to fit it into tubing like yours, or go on the scrounge for something more appropriate.

I wasn't going to put this on my helmet. I figured it is small enough I could almost get away with velcro'ing it to the front of the handlebar stem ... 

Edit: *grumble* The arctic silver costs as much as the all the rest put together! *grumble*


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## fre3ud (Apr 29, 2008)

That Optic may be able to be set flush on the front of the alloy tube - just have to make sure the end is cut/filed square so the lamp sits well.

Maybe look at this battery box instead to avoid the missing battery:
http://www.dse.com.au/cgi-bin/dse.storefront/4875dacb01010f48273fc0a87f3b067b/Product/View/S6153

You may find 3 freshly charged NiMH AA are over 4V - but measure them again under this load and they drop immediately to 3.8V and then gradually to about 3.6V, where they sit for most of the rest of their discharge.

High capacity AA seem to offer the best charge for weight compared to 4/3AA, c or D NiMH. LiIon are lighter but more expensive and fiddlier to charge etc etc.


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## znomit (Dec 27, 2007)

fre3ud said:


> You may find 3 freshly charged NiMH AA are over 4V - but measure them again under this load and they drop immediately to 3.8V and then gradually to about 3.6V, where they sit for most of the rest of their discharge.


Yeah, lots of AA NiMH discharge data here.


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## glowinthedark (Jul 8, 2008)

fre3ud said:


> That Optic may be able to be set flush on the front of the alloy tube - just have to make sure the end is cut/filed square so the lamp sits well.


Yeah, I had a similar thought -- I could go with a smaller id tube if need be. I have some ex-curtain tubing in the shed, so I'll start by rifling around in there to see if I can find what I need.



fre3ud said:


> Maybe look at this battery box instead to avoid the missing battery:
> http://www.dse.com.au/cgi-bin/dse.storefront/4875dacb01010f48273fc0a87f3b067b/Product/View/S6153


Thanks for the heads up. I was taken with znomit's suggestion of a switch with a resistor wired across it to give high/low. I did think this would fit quite nicely in the space left by the missing battery, but a smaller box seems very appealing. I take your point about using a proper current regulation circuit, but the cheap ones don't have the ability to change output and the nice ones cost more than the rest of the setup put together. I like the high/low thing mainly from a heat regulation POV. I can switch to low when stopped and have less chance of cooking the LED.



fre3ud said:


> High capacity AA seem to offer the best charge for weight compared to 4/3AA, c or D NiMH. LiIon are lighter but more expensive and fiddlier to charge etc etc.


I like NiMH. For a setup like this the weight difference is negligible, I already have a nice NiMH AA charger and pulling 3 cells out and charging them is no real hassle. Sweet!

In your design I noticed the lead you wired on to the light had a nicely moulded plug on the end. Did you scavenge that from another piece of grear, or can you buy moulded plugs with leads already attached? (this will save me soldering, and I am crap at soldering and plugs seem to be the thing I am crappest at).

Now all I have to do is push the "Checkout" button at cutter.com.au .... :yikes:

EDIT: DONE!


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## fre3ud (Apr 29, 2008)

glowinthedark said:


> I like the high/low thing mainly from a heat regulation POV. I can switch to low when stopped and have less chance of cooking the LED.


The resistor method continues to draw current - but just wastes it as heat - better to switch off and use an auxilliary light for stationary conversations etc



glowinthedark said:


> In your design I noticed the lead you wired on to the light had a nicely moulded plug on the end. Did you scavenge that from another piece of grear, or can you buy moulded plugs with leads already attached? (this will save me soldering, and I am crap at soldering and plugs seem to be the thing I am crappest at).
> EDIT: DONE!


Just hacked it off an old plug-pack - for a desk-top calculator I think. I literally have boxes of old power packs scavenged after each generation of office equipment is dumped.

Phil


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## glowinthedark (Jul 8, 2008)

fre3ud said:


> The resistor method continues to draw current - but just wastes it as heat - better to switch off and use an auxilliary light for stationary conversations etc


Yeah, point taken. Might still be useful for dimming, but it makes it more complicated than it needs to be.



fre3ud said:


> Just hacked it off an old plug-pack - for a claculator I think. I literally have boxes of old power packs scavenged after each generation of office equipment is dumped.


Yeah I guessed as much, so I had already done the same thing. Saves one lot of soldering. I also managed to find some Al tubing in my shed with pretty much the same specs as you described. Bonus. It is all I can do to stop myself from hacking bits off it already. It is painted white however. Sandpaper ... hmmmm.

The only other major bit to source is a solid bit to shove in as a heat sink. I am not mounting it in the same way as you did, so I need something inside to mount the star to.

Thanks for the help


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## glowinthedark (Jul 8, 2008)

*Mounting idea*

My idea for mounting this small light is shown in this crappy drawing:










Basically the idea would be to cut a slit in the top and bottom of the tube and run a hose clamp through the slits. I would shape the tube (and heatsink?) where it buts up against the handle bar to make it grip nicely. Some rubber could be put between the tube to make it grip better, but I doubt it would be required.


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## fre3ud (Apr 29, 2008)

Mine was just zip-tied to the head tube of the bike and the 3 x AA NiMH goes in a small feed pouch.


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## glowinthedark (Jul 8, 2008)

*Finished light*



fre3ud said:


> Mine was just zip-tied to the head tube of the bike and the 3 x AA NiMH goes in a small feed pouch.


Nice and simple. This is what I was thinking:










That size hose clamp is total overkill. A smaller one would be easier to fit and wrap around the bars more easily. As it was it took 15 minutes to make. I cut the two slits top and bottom with a hack saw (at the end of the tube) and then cut through the tube to leave about 25mm total length. Easy as. I shaped grooves into the tube where it sits on the bar handles, but did a little more after I took these shots. The hose clamp put enough pressure on that it bent the Al tube a little where it went through. Still strong though, and this would happen less with a smaller hose clamp and if I'd shaped the tube more where it mates to the handle bar.

Here is another shot from the front:










and the back:










The CREE optic plus LED plus metal star PCB is about 15mm deep, so there should be plenty of room for a disc of Al as a heatsink. The optic I chose was too wide to fit in the tube (the fraen would be a better choice I guess) but it could be sanded/trimmed if required. If I was going to finish this light, I would look at using the end of a Berocca tube with a circle cut out as an end cap to keep water and crap off the lense. According to this site  it should fit fairly well.

BUT .. I don't have to finish it, as an engineer at work (with loads of creativity and some spare time when I asked him for scrap Al for the heatsink) machined this for me:










Sweet eh? The barrel that the led and heatsink sit in screws into the mounting bracket and there is a hole in the inside of that threaded screw that the power leads run through. He even machined a threaded cap with nice finger grip.

I have put some overhead projecter film inside the end cap to protect the lense from dirt and dust and am very happy. I haven't even epoxy'ed the LED heatsink to the Al body. Not sure I have to either. I am driving it straight from 3xAA (2500 mAh NiMH jaycar cells). So far I have used it 7 times for my commute home (25 minutes at a time) without recharging and it is still bright as.

This is my battery mounting:










It is an old sunglasses bag, doubled over. It is soft enough that I can operate the switch on the DSE 3xAA box (referred to earlier on the thread) through the bag. I got the velcro stuff from Bunnings, I can't recall what they called it but it was expensive ($7 for 2m) and it had a picture of it being used to hold a bike pump to a top tube as an example use. It is very good and strong and I highly recommend it.

I had to buy a female in-line DC plug to match the one I cut off a power pack. I am such a crappy solderer that I melted the inside pin on the female plug so that it drooped to one side. I had to heat it up again and try and straighten out the pin. In the end it is still a bit wonky but this makes the plug connection nice and tight! :thumbsup:

If someone else was trying this, I might suggest they buy this 5m DC extension cable from jaycar. Then you could cut it and join the female end on to the leads coming out of the 3xAA box and the male end to the light unit. Soldering wires is ALOT easier than soldering plugs I reckon.

Here is the finished product, beaming out at ya! WOO HOO! 










I can't recommend highly enough this direct driving method for cheap commuting lights like this one. This is $18 worth of parts (+$12 for AA cells) and $10 worth of postage. I wouldn't bother with the arctic silver next time (I have some, unopened, still in the bubble wrap from Cutters, anyone in NZ/Aus want to take it off my hands for, say, $10-12 + postage?)

By the way, thanks to the folks at Cutters. I ordered on a Friday and it was delivered by the next Wednesday. Couldn't be happier. :thumbsup:

Thanks for the advice from those on this forum.


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## znomit (Dec 27, 2007)

glowinthedark said:


> I can't recommend highly enough this direct driving method for cheap commuting lights like this one. This is $18 worth of parts
> .


Nice job. Would have liked to see the cheapo one finished!
You haven't coated the inside of your light with glow in the dark paint?

For a few dollars more the 500mA micropucks give regulated light for 2.5-3hrs of 2AAs. Also means you can run off standard AAs as well an NiMH. They about 12$


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## glowinthedark (Jul 8, 2008)

znomit said:


> Nice job. Would have liked to see the cheapo one finished!


I hope to finish it at some stage, but there is no real urgency now. I just have to source a Berocca tube and some scrap Aluminium.



znomit said:


> You haven't coated the inside of your light with glow in the dark paint?


The lens holder pretty much completely blocks the inside of the light .. unless you mean paint the lens holder?



znomit said:


> For a few dollars more the 500mA micropucks give regulated light for 2.5-3hrs of 2AAs. Also means you can run off standard AAs as well an NiMH. They about 12$


I was keen on the lack of complication of directly powering the LED.I would have to wire the puck in somewhere. I did think it would be possible to wire a micropuck into some wire with DC plugs on either end, so you could use the micropuck just by putting it in between the battery box and the leads to the light.

As it is I can power a second LED off the same battery box just by putting it in parallel. Run time would take a hit, but I'd be using it mainly as a "high beam" option for particularly dark bits of my commute. I would have to purchase another driver to do this.


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