Postby Tojja on Fri 16/Mar/07 1:08pm

To quote myself:

I warn you, there will be some LED anorak-ness. I will give practical recommendations, but this will be woven into a tapestry of lumenous efficiency and thermal management :P


If this is too hard, go to Nightlightning or make a halogen based light
Tojja
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Postby porschenut on Fri 16/Mar/07 1:09pm

Tojja wrote:
I warn you, there will be some LED anorak-ness. I will give practical recommendations, but this will be woven into a tapestry of lumenous efficiency and thermal management :P


If this is too hard, go to Nightlightning or make a halogen based light.
[/quote]


How bout you make it and I pay you to do it? ;)
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Postby Tojja on Fri 16/Mar/07 1:12pm

Now you're talking. We'll cross that bridge in the next week or two however.

I will edit the info over the weekend so make it easier to understand and fill out the empty sections
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Postby JoeMarshall on Fri 16/Mar/07 1:28pm

porschenut wrote:
Tojja wrote:
How bout you make it and I pay you to do it? ;)


D'you have access to a soldering iron, at uni or at home (or know some elec engineers who'll let you use theirs)?

I'm a software person myself so don't mess with hardware if I can help it, and I had no problems making a set of 3 LED lights as my first ever soldering project, and a 1 LED light as my second. (using 'how to solder' instructions off google).

Once you've worked out what to buy (which should be pretty straightforward once that post is finished), the hard bit isn't the electronics, the hard bit is working out how to mount it on your bars nicely.

Joe
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RE: Building And Led Bike Light

Postby JoeMarshall on Fri 16/Mar/07 1:51pm

Tojja wrote:... lots of stuff ...


That looks fantastic, be interested to see the rest of it.

Only things I'd say is I'd still be careful about recommending Seoul LEDs until you're sure there's a decent 3 LED optic or reflector easily available for them.

As far as number of LEDs goes, there's two things I'd note - firstly that you can run a single LED setup, for emergency and road use (and to make a really tiny tiny light that will run off AA batteries, using the cutter kit). Also, that if you want to use a single optic for all LEDs, currently only the 3 LED ones suit stars, so 4 LED lights need to use individual optics.

Oh yeah, when you're writing about heat and casings and stuff, I'd say assuming like you said, you're running at 700ma, special heatsinks are generally not worth bothering with. If you're having to use a heatsink, that's quite likely a sign you've designed the casing poorly. If there's any chance you can use the casing directly as a heatsink, that's so the way to go, both in terms of weight, and heat efficiency. Also, that if you're testing for heat issues, don't worry about trying indoors, do it outside in the dark, as overwise you'll end up over-building and making a heavy lump that will work fab if you're nightriding without moving in 28 degrees C and completely still air. What testing inside is good for is testing heat transfer. If you run it inside, and the outside of your lamp unit doesn't get warm or hot, then you're probably not getting any heat transferred out, this is probably a bad thing.

Oh and another common heatsink thing that people seem to do all the time with these lights, putting a heatsink inside a tube, but not touching the exterior casing, so there is no heat transfer to the outside, what a random idea.

The TaskLED boards - one of my mates back in the UK has one of these, apparently you set up which of a number of dimming / flashing etc. levels you want to use once when you build the light, and that's it, once you've done that, it's great to use, the same as any other clever light.

Joe
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Postby Tojja on Fri 16/Mar/07 2:39pm

I am aware of the seperate versus cluster optics considerations (and impact on the number of LED you choose).

You know about the quad-LED Cree optics available though eh?

http://www.cutter.com.au/proddetail.php?prod=cut559

When I write that section, will show all the options.

Maybe hold off on comments until more finalised this weekend.
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Postby JoeMarshall on Fri 16/Mar/07 3:09pm

Tojja wrote:
You know about the quad-LED Cree optics available though eh?
http://www.cutter.com.au/proddetail.php?prod=cut559


Yeah, have seen those, but was told that they wouldn't work with star PCBs and you needed to use a custom PCB for it, don't know if that's true though. The stars do fit perfectly under the 3 lens and I can't see how you'd fit four under though, they just don't tessalate nicely. Have just looked at the luxeon star datasheet (I think are same size/shape as cree stars) and I think they wouldn't fit, 19.9mm on the shortest dimension, about 20.6 on the longest.

Maybe cutter will release a quad LED pcb soon though, they already do 3 LEDs on one PCB for the triple lens.

Joe
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Postby Tojja on Fri 16/Mar/07 3:38pm

Hacksaw
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Postby philstar on Fri 16/Mar/07 4:01pm

Tojja wrote: Hacksaw


the star or the optics?

Tojja wrote: Now you're talking. We'll cross that bridge in the next week or two however.


and you don't cross bridges you burn them. :)
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Postby Tojja on Fri 16/Mar/07 4:03pm

The star, though I was being tongue in cheek...
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Postby Tojja on Mon 19/Mar/07 1:38pm

A few updates to optics section (still work in progress).

JoeMarshall: It seems that some Optics intended for Luxeons work very well with Seoul P4's (such as these: http://www.ledsupply.com/l2-op-015.php).

The main issue is ordering a few of these (mix 5 and 15 degree) to play around with before committing to a larger batch to get prices down...

Following the optics route will cost around NZ$12-15 per 3 LED light. Reflectors are around twice this, but the reflectors I was intending to use (IMS20) need some modifications before they work with SS P4s. So optics looking more attractive
Tojja
Member for: 15 years 6 months

Postby JoeMarshall on Mon 19/Mar/07 2:22pm

Tojja wrote:
JoeMarshall: It seems that some Optics intended for Luxeons work very well with Seoul P4's (such as these: http://www.ledsupply.com/l2-op-015.php).

The main issue is ordering a few of these (mix 5 and 15 degree) to play around with before committing to a larger batch to get prices down...

Following the optics route will cost around NZ$12-15 per 3 LED light. Reflectors are around twice this, but the reflectors I was intending to use (IMS20) need some modifications before they work with SS P4s. So optics looking more attractive


This oval clip on lens looks clever

http://www.ledsupply.com/l2-opk2-1-427s.php

Seems to me you could have a pretty tight forward beam, but with good side visibility, which could be really nice for bar mounted lights?

Cutter do these too, for slightly more money, but might be cheaper/quicker for the postage from Australia?

Joe
JoeMarshall
Member for: 13 years 8 months

Postby nibbler on Mon 19/Mar/07 2:47pm

Your technical banter convinced me to take the plunge...

So far I have 3 Seoul LEDs, some Luxeon optics with a range of diffusers and a 3021 buckpuck running at 700ma. Plan is to install them in the housing shown below, which is made from Jaycar project boxes. It has a solid, almost industrial look, but should do the trick!

Upper mount holds 1 LED, and lower 2, both of these will be made from a cut down aluminium box, while the main box is a sealed ABS plastic one which should keep the circuits water free.
Some LED specific heat sinks mounted on the back should keep it running cool, as I've read that you can't sink it enough.
Assembly is designed for helmet mounting, and will be powered by 10 2500mah AA NiMH cells that can be individually charged.
Am going to use this driver circuit http://nobmob.com/node/981 , as the guy worked out some sweet dimming and low power features that should do the trick quite nicely.
Assembly.jpg
nibbler
Member for: 16 years 6 months

Postby Tojja on Mon 19/Mar/07 3:10pm

Yup, was just looking into Cutter now - rips my gruts to pay NZ$35 for these optics when I can get them from states at a third of that...gaaaargh!!

Note that the optics you linked to are a different range - I am not sure they work with SS P4s

I will get a few 5 degree, a few 15 degree and one of these ovalised and see how they look
Tojja
Member for: 15 years 6 months

Postby ryda on Mon 19/Mar/07 3:11pm

Has anyone managed to buy anything from cutter ?
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