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  1. #1
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    4x xpg road light and 2x xrc tail light ($100 build)

    Just got done with my new headlight and I figured since this forum was where almost all my research for this light took place I'd post the results (also I'm so happy with it I felt I had to show it off a little ).


    Headlight Parts (and approximate prices):

    4 Cree XPG Leds ($24, dealextreme)
    4 Regina Reflectors ($10, digikey)
    2 Dealextreme Drivers ($7 for 4 drivers, dealextreme)
    3/4 inch aluminum tubing ($8 for enough to make about 4 lights, local hardware store)
    1 power switch and boot ($4)
    1 toggle switch (free - had on hand)
    1 XT60 battery connector ($3 for a 5 pack, hobbyking)
    1 optical plastic sheet for lens ($6 for enough to do at least 30 lights, home depot)
    1 adhesives - silicone and jb-weld ($5, home depot)

    Taillight Parts:

    2 Cree Red Led (I believe XR-C) ($7.5, dealextreme)
    2 FA10306_CRS-O oval lenses ($6, digikey)
    1 555 flasher circuit (free - had parts on hand)
    1" aluminum tubing ($8, local hardware store)
    1 XT60 connector (no cost - extra from headlight)

    With shipping the total for all this would be about 100 dollars, which is exactly what I was aiming for since being a college student precludes spending a lot of money. In reality I did spend a bit more to take advantage of bulk discounts both on digikey and dealextreme but for the purposes of this build I consider its cost at about $100. Not bad for a 1000+ lumen headlight and 200ish lumen taillight.





    The mounts pictured are spring loaded and are about halfway done in that picture. They have since been finished and are in the anodizing tank as I write this. They make removing the light really easy and are surprisingly strong (the light doesn't shake on bumpy roads/potholes). This would also be a good place to mention I learned to anodize just for this light, the setup to do it surprisingly only cost about 60 dollars in parts, but that's a project that deserves its own post.

    Unfortunately I don't have many pictures of the tail light as I made it several weeks before the headlight and wasn't thinking about documenting anything at the time...

    Installed permanently under the seat:


    Tail light sitting next to a light that was the prototype for my new headlight:





    I guess I'll write a bit about how I made it as that seems to be the norm around here I'm sure many of you have spotted that the amoeba light was a big inspiration in what housing materials to use (Thanks Scar!).

    Here is a pic of my very modest machine shop, this is pretty much all i used to make them (plus a couple measuring/marking tools):


    I started by measuring and marking the aluminum out, and then cutting it just a hair large with the dremel, I used the hand files and a square to file everything to exactly where I needed it (man do I wish I had access to a mill):


    Then I drilled holes for the wires and switches:


    Unfortunately the camera was broken for a while so I missed the anodizing and jb-welding process but it's easy to imagine. I jb welded the front 4 squares together and wired and thermal pasted the leds to the back tube. After that I jb welded the front 4 square assembly, the leds, and the back tube together. The 16mm stars I used fit absolutely perfectly inside the 3/4 aluminum so centering wasn't an issue:


    I had to do some thinking to figure out how to cut the regina reflectors to size as they were far too large to fit in the 3/4 tubing. I measured how much I would need to remove from the front of the regina and found a couple pieces of scrap aluminum which when placed under a hacksaw blade made a cutter the height of what I needed to remove. This is all on a very flat surface so I then just placed the regina face down on the table and slid it across the face of the clamped down hacksaw blade. This made a nice clean cut:



    I surrounded the edges of the opening with a silicone adhesive (put a lot in the corners) and pushed the regina in. This causes the silicone to surround the regina and also fill in the corners so you can't see the empty pocket behind. There was enough silicon left that I could just drop the squares of "Optix Acrylic Sheet" (found at home depot) I had made on top and everything sealed up nicely:


    Here was by far the most difficult part of the project; fitting two drivers, a large battery connector, two switches and a whole lot of wiring inside a little more than an inch and a half of 3/4 inch tubing. The drivers, connector, and toggle switch took some modifying to make them fit:


    The XT60 connectors are a very nice, snug fitting unit that feels tight enough I don't think rain will be an issue. The main reason I started using them was because I wanted to use the 3s lipos from my rc airplane. I think you'd be very hard pressed to find a better connector for about a dollar a pair. The only issue is that they are a little over 3/4 inch long so I had to do some careful cutting on the back of them with my dremel. Also while having the connector inside looks great it blocks almost all of the 3/4" tube making wiring and placing the other stuff in the tube incredibly difficult. You'll need some amazing soldering and wire management skills if you want to pull it off.

    On a side note I busted the inductor on one of my drivers (dealextreme sku 3256) while trying to stuff it in there. Anyone know what value the inductor is? I don't have an LCR meter and would like to salvage the driver by soldering a new one on.

    After finishing the light I cut up several heatsinks to make one big one for the bottom (which was anodized before being jb welded on):



    Finally finished:



    Some relevant info:
    -I'm running 2 xpg leds per driver (wired in series)
    -The black switch turns off power to both drivers, the toggle switch turns off power to one driver (the high beams)
    -Before installation I upgraded the diodes and current sense resistors on the drivers. The original diode is good for one amp so I replaced it with one that could handle 2 amps just to be safe. The drivers are ax2002 based so by changing the the current sense resistor you can just use the formula (.25/resistor = amperage out). The center two leds are run off a driver with a .47 ohm resistor meaning they run at a little over .5 amps which if I'm reading my datasheets correctly gives about 400 lumens out on my low beams. The outer leds are run off a driver with a .162 ohm resistor giving me 1.5 amps out which I believe equates to around 800 lumens making a total of 1200 when everything is on. This is just a guess as I lack the equipment to measure them properly.

    I don't have much for pictures of the tail light but if anyone is interested in how I made it flash or wiring just let me know.

    Time to go take the spring loaded mounts out of their sealant bath (the anodizing is finished)

  2. #2
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    Very good build with common household tools, thanks for sharing it. Ingenious mounting method too! Do you think there will be any waterproofing issues using JB Weld for the main light construction? I need to do similar construction work and am looking for a suitable method of holding everything together!

    Thanks for the breakdown on how you manufactured everything and put it together.

  3. #3
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    Thats a great build!
    DIY LED Bike Lights:
    A few Dynamo builds and some Small battery lights

  4. #4
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    Quote Originally Posted by mfj197
    Do you think there will be any waterproofing issues using JB Weld for the main light construction?
    Absolutely not. The only weakness I see where water is concerned is the toggle switch but I plan on ordering a rubber boot for it. The JB weld is an epoxy so water wont affect it and when you are putting it together it is somewhat runny so it will flow into any cracks or crevices, just apply it generously. It makes an incredibly good seal and is very strong stuff. Just remember if you are impatient and use JB-kwik weld (which sets in 4 minutes instead of 4 hours) that JB-kwik has half the strength of regular JB-weld.

    Check out posts 39 and 41, if Scar doesn't use JB weld in the amoebas then it is something very similar:
    ~1000 lumens helmet mounted

    Also note when I was putting it together it tended to squeeze out of the parts when clamping. It got all over the bike light and my hands, I found pure alcohol (in my case a splash of Everclear on a rag) will wipe away any excess as long as it hasn't set yet.

  5. #5
    Spanish biker
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    Very good job, congratulations!!!!!!

    Greetings - Saludos

    msxtr
    Warning!!! my english is very very bad, sorry.

    Easy DIY led light1
    Easy DIY led light2

    The Beast!!!

  6. #6
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    beam shots?!

  7. #7
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    Very nice build and write up.

  8. #8
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    Thanks for the compliments guys, just got back from testing the mount out now that it's finished, it performed admirably:





    That last image kind of shows how it works, there are 4 springs on each side. 2 main springs that push the arm inward to hold the light, a smaller tension spring above the main ones that pushes lightly toward the outside so that when no light is in it doesn't rattle or vibrate, and one small spring above the arm that the bolt goes through which keeps downward pressure on the arm to prevent any rattle or vibration when no light is in there.

  9. #9
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    Cool


    ***

  10. #10
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    very neat. Looks like an extremely well thought out project with lots of cool details.

    you should have absolutely buckets of light out the front. What's it going to be used for, randonees? It might be worth thinking about a shroud over the top, so you can get the reach you need for speed without blinding oncoming drivers.

    Interesting to see another build with 3/4in tubing. I can see why people use it over 1in. sq tubing (lighter, less clunky), but it does seem to have it's own compromises, notably fitting stuff inside and having to trim reflectors. Any reason you went with 3/4 for the front instead of the 1in you used for the rear light (which is also very cool)?

  11. #11
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    Quote Originally Posted by mattthemuppet
    very neat. Looks like an extremely well thought out project with lots of cool details.

    you should have absolutely buckets of light out the front. What's it going to be used for, randonees? It might be worth thinking about a shroud over the top, so you can get the reach you need for speed without blinding oncoming drivers.

    Interesting to see another build with 3/4in tubing. I can see why people use it over 1in. sq tubing (lighter, less clunky), but it does seem to have it's own compromises, notably fitting stuff inside and having to trim reflectors. Any reason you went with 3/4 for the front instead of the 1in you used for the rear light (which is also very cool)?
    I wish I could find a design for a shroud that worked well but when I tried a bunch of different shrouds on the smaller prototype light nothing worked well, which is a shame since I hate having a significant portion of my light wasted as it heads toward the sky. It seemed like the shroud had to be at least as large as the light itself to be effective, thereby doubling the size of the unit. I didn't want a huge shroud since I remove the light a lot when I use the bike to commute in town and go shopping. Which also partly answers your question about 3/4 inch tubing. This headlight fits nicely in my pocket which was one of the more important features I was going for. The taillight had to be one inch since I didn't want to try cutting down the 20mm star and the optics fit excellently in 1 inch tubing. Also it is permanently bolted under the seat so I'm not too worried about theft and always leave it on there.

    As far as use, I do most of my riding at night during the summer. The bike trails can get pretty busy with runners and bikers here in Madison in the evenings so when I go at night I never have to worry about slowing down, also when it gets really hot in the summer I'd rather ride at night. I'm not familiar with the term randonee but it sounds kind of like what I do. At least once a year I'll make sure I get a long ride in. Got this light done just in time for Friday when I plan to ride 160 miles north

  12. #12
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    I'd love some more info on your rear light, if you have time?

  13. #13
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    What would you like to know about it? Parts used, wiring, optics?

  14. #14
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    Thanks for the quick reply.

    Info on the wiring and circuitry would be cool.

    I've got a Dinotte rear, that runs on 4xAA batteries, and I find that to be VERY handy when in need of an emergency battery replacement. Would a similar power source be a possibility with the flasher circuit you use?

    Basically, any info that you can provide would be most appreciated thanks.

    Nathan

  15. #15
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    4xAA batteries while possible is pretty low voltage for my circuit, lowest I run is 11v. I use a 555 timer IC which drives a transistor switch to flash my lights. The 555 requires a minimum of 4.5 volts although I'd bet when the AA's get down below 4.5v they are pretty much sucked dry anyways. Assuming the 555 works fine on 4xAA you would then need to find a transistor that saturates at a low voltage for your switch (shouldn't be too hard to find). If you are interested I can try to find the schematic and get it posted sometime tomorrow.

  16. #16
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    Awesome - that would be most helpful, thanks.

  17. #17
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    Photobucket


    The Irfz44n transistor I used has a fairly high saturation voltage and won't work with your 4AA setup, I only used it because I had a bunch laying around. It should be fairly easy to find one with a saturation voltage thats under 4 volts which should be all you need to change. I also replaced the variable resistors with fixed ones once I got it flashing at the speed I want.

    The box labeled "tail light" is the two power leds and deal extreme current limiting driver.

    I'll be on vacation this week so if you have any more questions it might take me a while to respond.

  18. #18
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    The box labeled "tail light" is the two power leds and deal extreme current limiting driver.
    Which driver did you use for the taillight and are you driving two led's with one driver?

  19. #19
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    I am driving both LEDs with one driver, it is a dealextreme driver found here. Those drivers can be modded by changing a resistor to get different amperage. I am actually overdriving my LEDs a bit by leaving the driver stock (900ma driver on 700ma leds) however I didn't have the right resistor to get 700ma and figured since the leds are off most of the time with the flashing that there wouldn't be any risk of overheating.

  20. #20
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    okay, just realized you are using RC battery packs to power it. I am looking to build a taillight with 2 leds but looking to use driver (SKU: 6190) from DE cause I want to have it run off one 3.7V cell. Trying to keep it small. HI, lo, and strobe mode is all i am after. Will it work? Thanks and sorry for the hijack.

  21. #21
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    Ratfink - I've never used 1 cell lipo drivers so while I'm pretty sure I know what I'm talking about, theres always the possibility I am wrong More educated people than myself may need to chime in here.

    With that said I'm fairly certain that 6190 driver will work for your purpose (one cell, 2 leds) however you will probably have to hook your two LEDs up in parallel to keep voltage low enough for one cell (and that driver). I'm guessing each will get 1/2 of the 1000ma that driver puts out. Depending on the led this may be ok however you have to keep in mind that if the 2 leds do not have the same forward voltage one may be getting more power than the other. Normally this is not an issue however if one LED for some reason goes out or gets disconnected all the amperage may then go to other. Again depending on your LEDs this may or may not be a problem.

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