where to buy diodes?

[chh]

I'm looking to buy some led's for a light project. Anybody know where I can get some? Regular old .5W would be fine. No need for the 1 or 3 watts, but I might be tempted if I could get my hands on one for a relatively inexpensive price.

[chh]

nevermind. A little free time on the internet answered my questions.

Second question. I want to mount a couple of led's to my helmet with a small power source that will fit inside the helmet. Either a 9 volt, or better, a lithium ion. I'm just now learning about the basics of the wiring and such. I'm not ruling out a 1 watt, but the power source and resistor sizes are a bit daunting. I'd like to keep it as small as possible. If anyone has any cool plans for an integrated led setup in their helmet I'd love to see them.

[Phil Winkler]

I think I wouldn't want to place a power source inside my helmet if there were any possibility it might burn up, etc. How would you like one of those lithium babies to melt down in your helmet while you are on rope?

Still, I want to find out more about these LED lights, too, to replace the lights inside my boat (all 12v.) .

[chh]

after a little reading you may be right. Lithium ion might not be the best source inside the helmet, though I think you could do it safely. 9 volt may be better provided it's sealed with something, and you would get a couple of the .5 bulbs off of it.

[Nico]

chh how about THIS

[chh]

chh how about THIS

That's cool, but I'm kind of set on having the led's placed in the brim of my helmet and the power source located somewhere else. This would point the battery right at my forehead lengthwise. We use something very similar while surveying. A single red led that attaches in the same way to a 9 volt. Pretty easy to see at a distance. I'm very new at this so I'm learning as I go. Probably going to take my Tikka apart later today to see what kind of components it uses and whether or not I'd be able to build/canabalize something like that for my purposes.

I did find a bunch of places to buy led's as well. Up to the 3 watts with the corresponding regulators and such, but I'm trying to keep the assembly as small as possible. Though a 1 watt or 3 watt would be ideal if I could get the power source and resistor and whatever else I need down to a small enough size.

Thanks for your input nico!

[Nico]

perhaps you could place the LEDs in the front of your helmet and run wires to wherever the powersource is.

[NZcaver]

That's cool, but I'm kind of set on having the led's placed in the brim of my helmet and the power source located somewhere else.

Coincidentally, several years ago my back-up light was just like this. I had a pair of 5mm LEDs mounted directly in the front of my helmet, and the wires ran to a small battery pack in the back. The battery was an old NiCAD pack, I think. The light wasn't particularly bright, but it worked. I even had a small switch inside the helmet, waterproof and all. Sorry I can't find any pictures of all this...

Eventually I removed the system, as headlamp technology improved. I now generally use an Apex as my main, and a Gerber Infinity Ultra single LED/single AA light cable-tied to the side of my helmet. I don't usually like that mounting style, but the Gerber is pretty small and bombproof.

Good luck with your idea.

[chh]

NZ caver,

that's pretty much what I want. A backup source. I had originally only planned on using 2 5mm LEDs mounted just like you did, but with the newer led's available at very reasonable prices I'm thinking about updating the project. The problem I'm at now is the power source. (I know nothing about electronics) Did you use any resistors in your setup or did you just make sure your voltage was on par with what you needed for your LEDs? I was also talking over a bike light project with a friend who's making a bike for his girlfriend. He want's to mount some lights inside the frame and we were thinking about a 3 watt there, with a similar kind of space issue.

[NZcaver]

Did you use any resistors in your setup or did you just make sure your voltage was on par with what you needed for your LEDs?

Oops, I forgot to mention that bit! When driving LEDs, the forward current is a critical factor.

To regulate the current, I wired a pair of tiny 1.5V, 25mA incandescent bulbs in series with my (parallel) pair of LEDs, all fed from a 4.5V battery pack. The bulbs do not light up, but are used because they make more efficient current regulators than regular resisters. For protection, I sealed the bulbs in a short length of small clear plastic tubing.

This is a simple, cheap, and effective alternative to conventional current regulation. I got the idea off a local caver, who kindly posted the design on his website.