Comments on: 700 lumen LED bike lamp

By: TalkingJazz

TalkingJazz — Sun, 06 Sep 2009 16:50:22 +0000

Quite nicely put together, although i’m not sure that using a heatsink is anything new with high power LED’s. I’e been seeing cheep 20w modules floating around on ebay quite a lot recently. Has anyone had any luck with these?

By: Wwhat

Wwhat — Sun, 06 Sep 2009 15:02:53 +0000

Intructables has really gone down in my view with all their forcing people to sign up and log in for more and more functions (although I understand the PDF being users only).
I used to have that site in my quicklinks but no more, you can’t even see the secondary small pictures without logging in.
It’s a pity, and an affront to people that submitted articles when he were more reasonable, but it shows that you should never put too much money on a single horse eh.

By: JD

JD — Fri, 04 Sep 2009 15:52:03 +0000

If one was to take a microcontroller and create a stobing circuit with this set up, one could find out the frequency of the stop lights around town with a few adjustments. :-) However, I hear it’s not highly suggested.

By: Xiejol

Xiejol — Fri, 04 Sep 2009 15:36:31 +0000

I’ve wondered why I haven’t seen more bright LED projects on hackaday. Check out candlepowerforums.com for some good info.

My light setup for my bike is a Marwi P7 conversion that puts out around 700 lumens. I don’t need an external heatsink, the one inside moves all the heat to the body. While stopped it gets hot quick, I have to dim it until I get moving.

By: pdf

pdf — Fri, 04 Sep 2009 14:43:31 +0000

Looks like Instructables closed down no login pdf link access. You may resume whining.

By: Rob

Rob — Fri, 04 Sep 2009 10:45:49 +0000

@dielectric:
I’m not disagreeing at all with what you’re saying I just wanted to note that with enough output you can actually feel some heat from LEDs out the front as well. I built a custom light a year or so ago that puts out around 800 emitter-lumens and you can feel some heat from that radiating out the front. Nothing even remotely close to an incandescent though (I managed to burn a hole in my TV with a custom incandescent I built which turned itself on when I wasn’t around, whooops)

By: Jason Knight

Jason Knight — Fri, 04 Sep 2009 06:11:13 +0000

With only R2′s, that’s only marginally better than my 3x Q5 setup – but I would suspect that the use of just lenses with no reflector backing means the cast and fullbrights aren’t as useful with much of the energy wasted – especially given the existing lens on the bulbs. Brute force instead of finesse.

Though I’m planning on my next build using R2′s, but I’m going with this reflector:
http://www.dealextreme.com/details.dx/sku.18842

Probably go with the same pucks I did for my existing unit:
http://www.dealextreme.com/details.dx/sku.3256

Just like my existing unit I’ll do one puck per bulb and put copper VGA ramsinks directly on the base of each bulb. I like the 14mm base DX has for the Q5′s.
http://www.dealextreme.com/details.dx/sku.11023

I’ve looked at the R2 on a premium star, but my parkinsons ridden hands aren’t up for cutting things down anymore – and really I don’t consider the 2-3% brightness difference to be worth the 20% price hike.

By: Man On Fire

Man On Fire — Fri, 04 Sep 2009 04:52:42 +0000

that’s not really a potentiometer, looks like he’s using a pre-packaged PWM module.

/at least i hope he is.

By: dielectric

dielectric — Fri, 04 Sep 2009 04:08:53 +0000

@roy:
power leds get really hot, but out the “back” side. some high-power led designs use some thermal feedback to keep the operating point sane, others just throw a big heat sink on it and let ‘em go.

By: roy

roy — Fri, 04 Sep 2009 03:31:40 +0000

i thought leds didnt get hot

By: tony

tony — Fri, 04 Sep 2009 02:33:12 +0000

I used that same LED tz, and built a custom current driver using an lm3401. the thing will project a beam 300 yards. need to get a proper lens on it, but i’m good with electronics, not optics.

http://i533.photobucket.com/albums/ee334/ajm8127/DIY%20Bike%20Light/00001-640×480.jpg

By: tz

tz — Fri, 04 Sep 2009 01:06:37 +0000

http://www.dealextreme.com/details.dx/sku.14413

Brighter and easier. Remove the reflector if you want a flood.

8.4v works, like 2 LiPos, or a Nimh “9v” (1.2 x 7).

Actually anything from just under 5 to 8.4 volts works, but it requires enough current, and will deplete batteries very quickly.

By: PDF

PDF — Fri, 04 Sep 2009 00:11:17 +0000

Before instructables whiners start, here is the direct-NO-LOGIN-REQUIRED-pdf-link;

http://www.instructables.com/pdf/700-Lumen-LED-Bike-Light/700-Lumen-LED-Bike-Light.pdf

I submitted instructions in obtaining PDF URL just from the article URL for any Instructables articles to Hack-a-day, I guess they didn’t like it.

By: epicness

epicness — Fri, 04 Sep 2009 00:06:06 +0000

Meh… Someone built a 2800 lumen light already. http://forums.mtbr.com/showthread.php?t=487467

By: sly

sly — Thu, 03 Sep 2009 23:23:04 +0000

now there’s a bright idea

1st pun :D