Apologies for taking ages to figure out how to post this lot - hail photobucket - here goes:
[FONT=Arial, sans-serif]Hi, [/FONT]
[FONT=Arial, sans-serif]Got rained off this afternoon so managed some time on starting light 2: [/FONT]
[FONT=Arial, sans-serif]Step 1: HEATSINK[/FONT][FONT=Arial, sans-serif] [/FONT]
[FONT=Arial, sans-serif]Salvaged a piece of aluminium heatsink from an old PII processor and cut a disk from it [/FONT]
[FONT=Arial, sans-serif]using a hole saw. Approx 50mm outside diameter. The central hole will eventually carry [/FONT]
[FONT=Arial, sans-serif]the LED +&- wires [/FONT]
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[FONT=Arial, sans-serif]The remaining bits from the alu plate [/FONT]
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[FONT=Arial, sans-serif]The housing for the light on this occasion is an aluminium tow-ball cover 1.75ukp. Ok [/FONT]
[FONT=Arial, sans-serif]I know this is not the most beautiful thing on the planet, but without a lathe (mine will [/FONT]
[FONT=Arial, sans-serif]be here in time to fabricate light 3 though) it is a quick simple solution. The disk above [/FONT]
[FONT=Arial, sans-serif]had its edges tidied a little until it became a good tolerance fit. The housing will act [/FONT]
[FONT=Arial, sans-serif]as a heat sink also. Personally I think this light when completed looks pretty ok too [/FONT]
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[FONT=Arial, sans-serif]STEP 2: Seating the LEDs[/FONT][FONT=Arial, sans-serif] [/FONT]
[FONT=Arial, sans-serif]Here are the three I will be using in this light, Cree R2s, WG fresh from DX. As you [/FONT]
[FONT=Arial, sans-serif]can see, they are really small even when mounted on stars. Hats off to you guys [/FONT]
[FONT=Arial, sans-serif]who work and solder with the bare emitters. On stars though, they are about the same [/FONT]
[FONT=Arial, sans-serif]size as a 1P coin. At this point, I used two AA 1.5v batteries and a little wire to [/FONT]
[FONT=Arial, sans-serif]check all three emitters lit up individually, just to ensure none were defective before [/FONT]
[FONT=Arial, sans-serif]progressing, happily each one lit up brightly. [/FONT]
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[FONT=Arial, sans-serif]This product I picked up from Maplin, comes in 80mm x 80mm sheet and is [/FONT]
[FONT=Arial, sans-serif]double-sided Thermal Adhesive Tape, this will be used to mount the LEDs to the [/FONT]
[FONT=Arial, sans-serif]heatsink [/FONT]
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[FONT=Arial, sans-serif]Here is one LED mounted to the adhesive tape, soon the reverse peel will be [/FONT]
[FONT=Arial, sans-serif]removed. [/FONT]
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[FONT=Arial, sans-serif]Here is the triple 30 degree optic (DX again) this thing is fantastically clear and looks [/FONT]
[FONT=Arial, sans-serif]and feels pretty scratch resistant. Of course I need to align the three emitters with [/FONT]
[FONT=Arial, sans-serif]the lens before I finally mount them [/FONT]
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[FONT=Arial, sans-serif]I upended the lens. You will notice I did not lay it face down on the bare chipboard [/FONT]
[FONT=Arial, sans-serif]surface, just in case it is not as scratch resistant as it looks, and laid the emitters [/FONT]
[FONT=Arial, sans-serif]into the aperture of each optic. The reverse side of the adhesive pad is uppermost [/FONT]
[FONT=Arial, sans-serif]now. Carefully I aligned the heat sink with the lens and gently pressed it onto the [/FONT]
[FONT=Arial, sans-serif]sticky.pads. [/FONT]
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[FONT=Arial, sans-serif]Here is the unit righted, bear in mind the lens legs are not fixed yet so the entire lens [/FONT]
[FONT=Arial, sans-serif]will simply lift off. But the objective of correctly centering the emitters is done. [/FONT]
[FONT=Arial, sans-serif]As you can see it looks good. Apologies for that bloody penny, I wish I had removed [/FONT]
[FONT=Arial, sans-serif]it as it seems to have crept onto nearly every picture so far [/FONT]
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[FONT=Arial, sans-serif]STEP 3: Soldering the Crees[/FONT][FONT=Arial, sans-serif] [/FONT]
[FONT=Arial, sans-serif]I was able to clamp the heat sink to the board for stability. Using a cheap 30w [/FONT]
[FONT=Arial, sans-serif]soldering iron I started wiring the stars together. If you are new to soldering, I politely [/FONT]
[FONT=Arial, sans-serif]advise that you first review some of the "soldering" videos on youtube. Cleanliness [/FONT]
[FONT=Arial, sans-serif]here is really important, solder simply refuses to stick to tarnished surfaces. If you [/FONT]
[FONT=Arial, sans-serif]get this part wrong, you will end up applying enough heat to melt rock and the likely [/FONT]
[FONT=Arial, sans-serif]outcome is damage to the emitters. Soldering is really not hard for this project. [/FONT]
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[FONT=Arial, sans-serif]You will note there are four contact pads on each star, two positive (+) and two [/FONT]
[FONT=Arial, sans-serif]negative (-) in this wiring scheme, I will choose blue cable to join negs and Brown [/FONT]
[FONT=Arial, sans-serif]to join positives. [/FONT]
[FONT=Arial, sans-serif]Here is a pic of the Buckpuck I will be using. [/FONT]
[FONT=Arial, sans-serif]I sourced these from ledsupplies. I ordered on a Saturday, they were on my mat by [/FONT]
[FONT=Arial, sans-serif]the following Tuesday - excellent. [/FONT]
Thiis the wiring almost complete, just the LED + (White) & - (blue) from the buckpuck to connect.
STEP 4: Connecting the Buckpuck driver:
Feed the blue and white wires through the heatsink and solder the white to a remaining positive
and blue to a remaining negative contact. IMPORTANT NOTE: Really you should first insert a rubber grommet
to isolate the wires from the raw-metal edge of the hole through which they pass, I didn't because I had none
handy, but I will at some stage open the thing up and correct this, you may as well do it properly first time around
Here I joined the blue and brown wires that will be the main feed from my battery, approx one meter long,
to the black and red wires from the buckpuck (red-brown, black to blue) I simply twisted them tightly
together then soldered them, and insulated them. though you may prefer to use cable connectors or blocks.
STEP 5: Installing the potentiometer (for dimming)
The potentiometer acts as a variable resistor, the one I chose from Maplin is a 4k 7 pot with a 50mm rotary shaft
I noticed that when installing this into the unit, the solder prongs sat very close to the metal edge of the housing.
To prevent any problems, I used long-nosed pliers to curl them and crimped them onto my wires before soldering
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It is important to temporarily make a test connection to determine the correct orientation of the yellow and grey[/FONT]
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wires before soldering. In my case, the yellow went to one outer prong and the grey to the centre. I found that by [/FONT]
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moving the yellow to the opposite prong reversed the action of the pot E.G. rotating the pot clockwise caused the[/FONT]
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lamp to dim (you may prefer this) but I made sure to wire so that clockwise rotation reduced resistance and made[/FONT]
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the light brighter. And hellish bright it is, usually after tests I had to wait a minute before my vision returned to normal 
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Using a 10mm bit, I drilled through the rear centre of the housing to accomodate the pot[/FONT]
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STEP 6: FITTING A BIKE MOUNT:[/FONT]
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I was lucky to have a few old bike lights hanging around from which I was able to liberate the mounts[/FONT]
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these worked perfectly, but I know you can source just the mounts from places on the net[/FONT]
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I drilled a .5mm hole so the self-tapper screw would bite, applied some clear adhesive and fixed the mount[/FONT]
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What you can't see in these pictures is the other part of the mount which is attached to the handlebars[/FONT]
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At this point, I also drilled a 3mm hole for the main battery cable to pass through, again, a grommet must be used[/FONT]
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here to protect the cable[/FONT]
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STEP 7 ASSEMBLY:[/FONT]
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I measured the depth of the lens from the face to the end of the legs[/FONT]
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I cemented the buckpuck driver into the housing so it would be stable, not good to have this rattling loose[/FONT]
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in there. I then applied a ring of clear sealant at an appropriate depth to hold the heatsink correctly,[/FONT]
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please note, this sealant only forms a ring BEHIND the heatsink, it is important that the heatsink is a good[/FONT]
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tolerance (tight) fit to the metal housing to help dissipate heat.[/FONT]
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I then applied model adhesive to the lense legs and carefully installed the heatsink and lens.[/FONT]
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I then applied a neat clear silicone bead around the lens to provide a watertight seal[/FONT]
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STEP 8: WATERPROOFING:[/FONT]
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No piccies for this bit, sorry, but simple all the same. I bought from Maplins a rubber switch boot[/FONT]
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cut the 50mm shaft from the pot down to about 15mm, removed the nut from the pot and installed the [/FONT]
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rubber boot and refixed the pot using this waterproof boot. (you will see this in final pics) now I was [/FONT]
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unable to find anywhere a rotary rubber boot, but you will find that you can grip the rubber, twist and [/FONT]
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release and the pot shaft turns and the rubber springs back to its normal position, I was suprised how well[/FONT]
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this thing worked. I also put a dab of clear silicone around the grommet where the battery cable leaves the[/FONT]
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housing. I am confident this thing could be used underwater without any fear of leaks - Having said that though[/FONT]
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I hope I never fall into water on the bike, but for riding in the rain, I know this thing will be spot on.[/FONT]
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STEP 8: NOTHING TO DO BUT ADMIRE YOUR WORK AND TAKE IT FOR A SPIN[/FONT]
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I am fortunate in so much as I own the amazing Makita battery tools for my day-to-day work[/FONT]
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this gives me access to three of these brilliant batteries[/FONT]
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For connection to my batteries I have fashioned a connector that slips in great and fitted an inline fuse to protect it.[/FONT]
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as you may have read above, runtime on full power was in excess of 10.5 hours so I can't give you a figure here[/FONT]
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as I dare not leave it on unnatended. I know draining Li-ion batteries fully is not good but I am more than happy[/FONT]
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with the runtime.[/FONT]
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I will post some beam shots soon (just waiting for the rain to stop here in UK) but I can confirm the light is very bright[/FONT]
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and when testing the runtime, after several hours running, in a centrally heated room, the casing was only mildly warm[/FONT]
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and certainly not hot so I think I got the heatsinking right. Making this light has been immense fun and the end result[/FONT]
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far beats my expectations. Of course, I cannot accept any liability for any problems or unpleasant suprises you may face[/FONT]
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if you attempt to build something similar, I only post this information to show what I did.[/FONT]
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Final note: This is my first ever build of anything electrical or illuminated and I express thanks to all at CPF for their[/FONT]
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experience which gave me the confidence to try stuff for myself.[/FONT]
