Scratch-built TriLux III (Bike Light) finished!

[nightrider]

Well I finally finished this build. 3x Lux III, 20mm reflectors, 3021 BuckPuck (1Amp) driver packaged in 1" square aluminum tubing. Powered by a 14.4v 2500mA NiMH battery pack.



See all build pics at: http://myfwyc.org/Timberlake/BikeLighting

Additional info (edited 11/26). I also clarified that this is a bike light in the post title.
- It's a bike helmet light (in the above configuration)
- The LuxIIIs are being driven at 1A by the 3021
- The LuxIIIs are TV1J bin
- The reflectors are 20mm IMS brand
- LEDs are "continuouly" dimmable via 5k pot.
- Weight 150g (without batteries)

Ok, it doesn't look as good as the CatEye Triple Shot, but hey, it was fun to build!
Link to CatEye: http://www.cateye.com/en/products/vi...d=7&subCatId=1

[greg_in_canada]

Cool. Is it rain-proof?

Greg

[nightrider]

Cool. Is it rain-proof?

Greg

Good question!
At this point I would say it could handle a light rain. The front lens is well-sealed (epoxy/plexiglass). Where the front cover fits onto the main body, it could use a better seal, so I'm glad you mentioned this. I was thinking of making a rubber gasket or running a light bead of silicone caulk at the seams.

[nemul]

very cool! .. JB Weld is some bad stuff! lol

[shiftd]

looks neat.

i like the finning

[bbaker22]

Good work. I like the comparison photos between the Lux V and TriLuxIII. The TriLuxIII looks much much brighter, which will probably affect the decision for my next build.

baker

[nightrider]

Good work. I like the comparison photos between the Lux V and TriLuxIII. The TriLuxIII looks much much brighter, which will probably affect the decision for my next build.

baker

Thanks for the kind words. It's my first scratch-built light. Lots of Dremel tooling and filing!

Yes the 3xLuxIII is about twice as bright as the LuxV. It's worth mentioning that the Lux V light in the photo has an NX05 optical lense, whereas the TriLuxIII uses 3, 20mm reflectors. They are powered from the same 14.4v power source in the photos (not at the same time). The Lux V is driven by a 700mA PowerPuck and the TriLuxIII a 1A 3021 BuckPuck.
-Allen

[andrewwynn]

This is exactly what CPF is for.. five stars.

-awr

[nightrider]

Thanks for the five star rating!

Anyone familiar with using the 3021 BuckPuck know why the 220uF cap is recommended across the DC input voltage if the wires to the power source are greater than 18" in length?

I'm using a 36" power wire between the battery and the 3021/light, and I did not put a cap across the input voltage. Seems to work OK, but will something get damaged by not having the cap in place. It's mentioned in the last page of this spec for the 3021 Buckpuck.

http://www.luxeonstar.com/3021-buckpuck.pdf

[DUQ]

Man thats awsome. Can the light be staged, 1, 2 , 3 all on?

[nightrider]

Man thats awsome. Can the light be staged, 1, 2 , 3 all on?

Thanks!
No. It just has continuous dimming for all 3 at once. The dimming is provided via 5k pot combined with the 3021 BuckPuck. http://www.luxeonstar.com/3021-buckpuck.pdf

I'm building a dual Luxeon V light that will allow one or both on but will not have dimming capability. (Next project)
-Allen

[andrewwynn]

i think the cap is for RF control.. run it near a car radio it'll probably knock it right out.. had problems with my megasonic doing that.. the light is a wonderful show of CPF ingenuity.. deserves the rating.

-awr

[nightrider]

i think the cap is for RF control.. run it near a car radio it'll probably knock it right out.. had problems with my megasonic doing that.. the light is a wonderful show of CPF ingenuity.. deserves the rating.

-awr

OK. So it's just to keep me from causing RF interference.
Thanks again. Great forum!

[Pinter]

Nice light!
Some words on the 12xAA battery pack. Check the voltage drop on the battery holder at full power. Before my LiIon pack I used the same NiMH setup but the holder itself consumed a lot of power. Contact resistance of 24 battery contacts results in huge loss. Measure the voltage of a single cell directly under load, then measure the same battery after their contacts (e.g. on the next cells).

[georges80]

Thanks for the five star rating!

Anyone familiar with using the 3021 BuckPuck know why the 220uF cap is recommended across the DC input voltage if the wires to the power source are greater than 18" in length?

I'm using a 36" power wire between the battery and the 3021/light, and I did not put a cap across the input voltage. Seems to work OK, but will something get damaged by not having the cap in place. It's mentioned in the last page of this spec for the 3021 Buckpuck.

http://www.luxeonstar.com/3021-buckpuck.pdf

Input bypass/bulk capacitor. The buckpuck is a switching supply, it draws current from the input in large spikes. If you have long leads between it and the battery - during the large current spikes you will get largish voltage drops along the long leads. Putting a large cap close to the input pins of the circuit will improve efficiency and generally make the circuit "happier"...

Presumably they have an input capacitor already on board - but probably not big enough to deal with longer leads.

george.

[IsaacHayes]

Looks cool!

Here's a tip when bending aluminum: (notice the stress cracks at the edges of the bracket), heat it up first!

[nightrider]

Some words on the 12xAA battery pack. Check the voltage drop on the battery holder at full power. Before my LiIon pack I used the same NiMH setup but the holder itself consumed a lot of power. Contact resistance of 24 battery contacts results in huge loss. Measure the voltage of a single cell directly under load, then measure the same battery after their contacts (e.g. on the next cells).

The pack measures 16.2v at the connector (no load) and 14.25v under full load of the light. I'll have to check the single cell method you suggested. The light draws about 770mA from the battery pack under full load of the 3021 buckpuck + 3x LuxIIIs. I'm using 2500 mA NiMh AAs.

I'd rather have a nice solder-tab, shrink-wrapped pack, but these cheapo AA holders seem to work for now. I've actually been using them for 3 years, driving 10w halogens. I just recently replaced one pack because the AAs were becoming loose and rattling around in the packs, causing my lights to ocassionally blink. Additionally, I can use the AAs for other purposes (digicam, flashlights, etc) during the summer (when I usually don't night ride).

[nightrider]

Looks cool!

Here's a tip when bending aluminum: (notice the stress cracks at the edges of the bracket), heat it up first!

Thanks. I obviously don't know much about metal working. This my first ever time working with aluminum. I'm not really sure how much to heat it, so I guess I should practice on some scraps huh?

Thanks for the tip!

[nightrider]

Update.

I've just added some photos revealing my reflector fiasco when building this light. It's a little embarrasing here on CPF, but hey, I'm still "unenlightened" so I can make mistakes. You guys will proabaly get a kick out of this.

I originally designed the front cover of the light to fit NX05 optics/holders. At the last minute I decided to go with 20mm IMS reflectors. Now my front cover did not fit, so I proceded to hack on the base of the reflectors to make them shorter. When I fired up the light, the beams were totally hosed! So as a salvage, I glued the reflectors onto the top of the star's pcb and got most (but not all) of the beam back. New reflectors on order.
Confessional Photos Follow:

[IsaacHayes]

I'd say you'd have to use a blow torch. Don't get it too hot or it will crack/tear as well. Aluminum is more brittle than steel is. It doesn't give much before it tears/cracks.

Sounds like you're still tweaking it, but great job on the design of using square tube. It looks much more custom than that!

[BryGuy]

Don't worry about the confessionals...that's how I learn some of what not to do!

BTW, handle your optics as little as possible, mine are all scratched up and I thought I was being careful with them.

How do you think a 3 way switch (off, resistor for low, no resistor for high) would work as a sub for the pot? I'm assuming you have it rigged like fig 9 on the buckpuck data sheet?

Can you compare/contrast between the optics/reflectors in everyday use? Road or trail?

Love these bike light posts!

[nightrider]

How do you think a 3 way switch (off, resistor for low, no resistor for high) would work as a sub for the pot? I'm assuming you have it rigged like fig 9 on the buckpuck data sheet?

Can you compare/contrast between the optics/reflectors in everyday use? Road or trail?
Love these bike light posts!

3-way switch would work fine, I almost went that way as it was hard to find a 5k pot that would fit into the body of my light. Yep I've got the figure 9 setup (except driving 3 Lux IIIs).

My night riding is trail only. The reflectors provide more intesnse spot beam, with ample spillover. Optics... well I guess it depends on what you use, but potentially more flood at the cost of throw.. I am not an expert in that area. I like more spot beam coming from my helmet, and a little more floody light mounted on the handlebars. Helmet + handlebars is the way to go, in my opinion, for the trails. Handlebar light is lower angle and causes shadows to be cast on the trail, giving you better indication of stumps, bumps, etc. The helmet light has the advantage of casting beam where ever you look. So the combo is great. If I had to have only one, I'd go with helmet mounted light though.

[andrewwynn]

you definitely want to use an audio or log taper pot.. it's really nice with the buckpuck!

you can cut down a 20IMS but need to cut the FRONT off.. another common mistake is to try to take down an optic from the sides vs the front.. cute building up legs to temporarily fix the oops.. so are you going with 17s? you'd probably still get more throw with 20s that are cut off on the front.

Oh.. btw.. there is a tiny 8-level digipot i use in my VIP light.. it's exponential so absolutely perfect for this kind of dimming solution.

-awr

[nightrider]

The buckpuck docs say to use linear taper pot, but I think a log taper would work better too. It's very touchy on the low end with the linear pot.

I'm still going with 20mm reflectors; making new, longer case front. Will not cut these at all.

The 8-level digipot sounds interesting. I'll have to look around for one.

[bbaker22]

So, I'm building a tri-luxIII version of a bike light and wonder: how are the reflectors supposed to fit onto the stars? Do the little feet sit down in the cutouts or are they supposed to sit on top of the board? Also, do I need to glue the reflectors down, or can I just rely on the compression from the lens to hold them in place?

thanks,
baker

[nightrider]

So, I'm building a tri-luxIII version of a bike light and wonder: how are the reflectors supposed to fit onto the stars? Do the little feet sit down in the cutouts or are they supposed to sit on top of the board? Also, do I need to glue the reflectors down, or can I just rely on the compression from the lens to hold them in place?

thanks,
baker

Yes, the little feet are supposed to fit down in the cutouts with the body of the reflector resting flush on the surface of the star. You can either put a drop of adhesive on each foot, or choose to hold them in place with a lens. But for a bike light, I prefer gluing in place because they would rattle around (especially on the trail). Obviously, my photos of the reflectors show how I screwed them up by chopping off at the base (in order to fit) so I ended up having to glue the legs onto the surface of the star.

- Good luck.

[andrewwynn]

you definitely need to use a log pot.. led dynamics will supply the wrong kind if you get it from them.. linear pot is just about useless.

The reflectors' feet fit in the notches if 20 or 27, just on top if 17.

I glue them on with silicone if i want them to stay put.. like in the case of one of my BAM mods.. where the reflectors don't touch the lens.

-awr

[Darell]

Since we're all learning here...

First off - GREAT looking monster you've got there. Secondly, I can tell you from lots of bike-light experience, that the cooling fins are likely not needed. They look cool, but the rush of air over the whole thing will do an amazing job of bleeding the heat to the atmosphere. Long ago when I used an L4 strapped to my handlebars, I realized that the L4 didn't even get warm while I was riding. If I turned it on, and sat it on my bench, it would be too hot to hold in just a few minutes. Passing air does a WONDERFUL job of bleeding heat away. Of course this assumes an ambient air temp of under 110° or so - and some effective way of getting the heat from the LED slug to the outside of the case.

[greenLED]

nice, really, really nice!

Don't worry about those confessions, we all have our little (or, in my case, looooong) list of mods gone bad - or dead- that we won't admit having.

[LightSward]

Looks awesome! I agree with the combination of handlebar mounted light and helmet light. I do a combination or road and trail riding out here in the outskirts of Beaverton, OR.