custom LED rear lights first go/prototype

[knighty]

couldn't find a decent rear LED bike light, so figured I'd make my own, and then cast it in resin to waterproof it

bought a few bits to build a small test one, was only planing to test with a few LEDs but them my HD crashed so I had some time last night while I was re-installing

rough plan was, yellow each side for indicators, solid on red for brake lights, and flashing red for normal bike light

bit bodged, just used the stuff I had lying around on my computer desk while I was reinstalling windows/software etc..

all went pretty well, I mostly just bent over the legs of the LEDs to join to the next one, knew I'd run a thin wire down instead for the proper one I'll use, so I did the last couple of lines of leds like that just to test (much tidier)

no idea what resistors I should be using for these, I've used 4 x 120ohm in parallel for now, they're just what I had to hand, not sure what wattage they are, running from 12v right now, they're ok as long as I only power up 1 set up at a time, if I light yellow and red together they all go dim :-o


PHOTOS:
2 lines of yellow LEDs, 2 lines of red LEDs, mixup of flashing RED leds, then 2 lines red and 2 lines yellow again


rear view


clean resin (from ebay)


mixed the first pour, 100ml resin, 1ml hardener, poured into old ice cream tub


wait for it to set, but still be tacky/sticky (like gel), mix and pour another 200ml in, the put the LEDs in face down, pour another 100ml in ontop


I know resin gets hot when it sets... but this got crazy hot, it melted the bottom of the ice cream tub, so I took it out as soon as I could


closer inspection... and most of the LEDs have melted (the crask in the resin was me taking it out too soon)


but... they (mostly) all still work ok



vid of flashing LEDs
http://imageshack.us/clip/my-videos/534/4hsfwkjiispeinfnnsokpw.mp4/

sorry some of the pictures are a bit crappy, it's pretty hard to photograph the LEDs in the resin

things to do differently next time...
I used some 5mm and some 3mm LEDs for the flashing ones, the 3mm ones were pretty naff, and then burnt out (probably needed a bigger resistor for those)
ordered some of the right resistors, and I'll put one on each leg of LEDs to keep them cool
the flashing LEDs are a bit naff, because they don;t flash in time with each other, from a distance it's not a bright light, more of a twinkling light - so I'll just use all normal leds, and then use a flasher relay to flash them

the resin is incredibly clear, like glass, but because the LEDs melted the light is more diffuse now, not as focused, no next time I'll cast it the other way up, I'll put the LEDs in face-up and I won;t cover them, Ill put in just enough to waterproof them (I think if I do small amounts I could keep filling it up a layer at a time to cover them if I need to)

might also spray the protoboard with silver paint, so it's a bit more reflective


that's it for now, I really need to wait for it to get dark so I can test it outside and see what it's like in the dark and at distance

these are 8000mcd LEDs... about the brightest I could find without looking too hard, might try to get some brighter ones for the final version

 

[cal3thousand]

Looks cool.

If you want brighter, more reliable (vibration-resistant) leds, look at the automotive sector and try SuperFlux (lumiled) leds. they are a 4 prong package to be more stable at the solder joint over long term vibration exposure (maybe not a big deal since you potted them) and they also offer a better light spread for taillights.

 

[alsmith]

couldn't find a decent rear LED bike light

It's great fun building your own stuff, but sometimes it's good to ask- often the many members here have a few who have looked for similar things. Strangely just a couple of days ago....

Anyhow, I found some that might have been of interest, with exactly the same lights being sold at much higher prices on other sites. It may be too late for you, but this might help others...

From less than $10 it shows 3 or 4 on page 2 (which it should open at) with loads of different styles on page 3.
Look at the cat-eye one for $7.22 or a 'Honda' one at $8.22. Plus Carriage, but the charges aren't like BMSBattery!

 

[amberwolf]

LumiLEDs are what I used for DayGlo Avenger's first lights and turn signals. Even just a cluster of 8 or 10 of them was pretty bright, daylight visible (barely). Plans were to make larger ones and put htem on CrazyBike2, but plans were delayed a long long time. Now I think all my LEDs are melted in the fire so are now cancelled.

But if you don't mind using household lights, Texaspyro sent me some "12VAC" tracklighting stuff that's all sealed LED that are friggin' bright, and are presently installed in my turn signals in place of the standard automotive bulbs (had to wire to the pins on the LED bulbs as they don't fit the auto bulb sockets). Have worked great ever since he sent them to me.

If you don't mind using red filters over them you can use them for taillights; amber for turn signals (red, too, if you like, but amber stands out better).

Then there are the regular PAR type LED spotlights, which you can power off your battery pack, probably, if it's high enough voltage to kickstart the built in power supply that normally runs off 115VAC. Those are bright enough for headlights, if you like.


But what makes a really good LED taillight is a motorcycle unit. You can buy the OEM ones or the replacements, sometimes pretty cheap, especially if you go to your local motorcycle parts shop and see if they have anything pulled off a bike when customizing it. That's what DGA and my trike both have on htem.

 

[alsmith]

.......
But what makes a really good LED taillight is a motorcycle unit. You can buy the OEM ones or the replacements, sometimes pretty cheap, especially if you go to your local motorcycle parts shop and see if they have anything pulled off a bike when customizing it. That's what DGA and my trike both have on htem.

That link is mainly motorbike leds after the first few inbetween all the other led stuff.

 

[knighty]

I saw some of those before, or some like them anyway.... but they're still not quite what I wanted

new super bright LEDs have turned up now (2400msd) and some more protoboard

I'll try and get a final board done this weekend


I'm going to scrap the flashing LEDs in the middle and use normal LEDs and then a 12v car flasher relay instead, they all need to flash in time with each other to be really effective

also means I can have them all flashing, and then turn them all permanently on as a brake light