DIY taillight questions
 

To start off, I have no prior experience with electronics or lights. My goal is to make an on/off (aka non-flashing) red light with around the brightness of a superflash (to supplement my current one). I'm planning on not using a lens, since my superflash often shines straight into the ground on (numerous) downhill/uphill transitions on my commute.

Based on other projects I saw here and elsewhere, i thought about using two of these red crees:
http://www.dealextreme.com/details.dx/sku.1776
and possibly this on-off switch (i don't really know how to choose one, but I'm guessing anything that's not momentary would be okay?)
http://www.radioshack.com/product/in...ductId=3159591
with two nimh AA batteries (I don't know if that's compatible with the two "1.9~2.2v" leds either)

I know I also need resistors, but when I searched on radioshack.com I only found a bunch of 1/8w and 1/4w ones along with a few 10w 10ohm 5% (or something) and don't know what would be suitable for this application. Hopefully someone here can help me choose one?

Also, what should the LEDs be housed in? The only tools I'm probably going to have are a drill and some screwdrivers, so I can't really cut metal or anything (unless there's a good way to do that with a drill). And speaking of tools, is it vital to have a soldering iron? And if so, would an entry level $8-10 one work?

Thanks in advance.

(bump) anyone?
or should I just not attempt this given my lack of knowledge?

Well at that rate, possibly a 1AA LED flashlight with a red filter? Common matte-finish invisible tape makes a decent diffuser material too, so a layer of that would de-focus the beam nicely if you want a flood beam. I linked to a Rebel-emitter model since the "warmer" color would probably leave you more red tones than a lot of Cree emitters would give.

I happen to have a Fenix red filter coming from batteryjunction.com tomorrow, if you're curious to hear a report on how they work in real life. The Fenix itself is out on loan, but I can arrange a test with one of my other flashlights.

I feel like shillin' for my DIYs.

Teaser. PB SF on left, DIY using cree on right.
http://i129.photobucket.com/albums/p...s_mr/lite1.jpg

Check out the rest here.
http://www.bikeforums.net/showthread...557&highlight=

^seeing that, it seems I could get by with one LED

And after reading your thread and looking into controllers (mainly for the low-high option), how do you change the mode on one of them? I saw this on dx and didn't see any visible way to change modes or set voltage or anything. And does it replace the role of a resistor? (sorry about all the questions)

I thought you were against high-output taillights? :) But nice work there :beer:

As for housings i used marker lights for trucks. They're cheap(ish) at about $2.50 and the thing i like about them is you can get replacement covers. I find the red covers fade abit over time so the option to change them every couple of years appealed to me. Of course with the red LED you don't need a red lens, you can enclose them in anything that lets the light out and is water tight.

On-off momentary contact switch, I believe the link is somewhere in the thread I provided.

http://i129.photobucket.com/albums/p...r/DSCF4711.jpg

The yellow button is the on-off switch plus mode changing switch.

There's more. I upgraded. http://www.bikeforums.net/showthread...641&highlight=

Two of the same LED.

I still use PB SF regularly. I still maintain my original stance both of these lights are overkill.

Thanks for the replies. So so far here's what I'm thinking:

1. I buy soup from some chinese takeout and don't throw out the clear covered plastic bowl they give out (about 3" tall, 3-5" diameter bottom-top)
2. I cut a pipe holder metal strip (don't know how yet, but it seems pretty thin) and glue the red LED in the middle
3. I wire the2AA battery holder, the controller, and a momentary contact switch together.
4. I secure everything inside the bowl and fashion some kind of backpack clip (or something, haven't decided)

I still don't know if I need a resistor with the controller, nor do I actually know what order to put everything in. And for the switch, $2.69 and 120v for one switch seemed like a bit much. Is there something cheaper from dx or somewhere (like this) that's momentary and would work with a controller?

No resistor needed. I can't help you with the switch, you are on your own for that, check your local electronic supply stores, and 120V switch is overkill, but it is the standard. I go for the clicky momentary instead of plain momentary, you can't turn it off with just momentary switch alone.

FWIW, I used these, just a reminder switch varies on the type of enclosement you are using, I selected what's most suitable for my project. http://www.dealextreme.com/details.dx/sku.5604

YES and yes

2 AA batteries is only 3V, so even a 12V switch is way overkill

What's the point though. A superflash is $12. Without a lens it'll be craptacular.

Firstly, a superflash is more like $17-18

Secondly, I like the idea of having made my own light and being able to fix it (possibly) if something breaks. And finally, the whole point of this is to increase off-angle visibility - I already have my superflash flashing away at people within a 30 degree angle from my bike. What about hill transitions, turns, intersections, etc? It might even be brighter than the superflash from straight behind considering the superflash can run off 2AAAs for a hundred hours.

The red cree hasn't shipped yet (it was backordered for weeks and is still "pending"), but i wanted to know how to wire this thing for when it does come. I tried searching on google for wiring diagrams, but I only found ones for the cheap 20-for-$3 kind of leds, and especially not for ones with a controller. So how should a controller, LED, battery case, and switch be wired?

I think it's going to depend on your controller... do you have a link?

here is a resistor calculator

http://led.linear1.org/led.wiz

http://myfwyc.org/bikeled/images/SeriesWiring.gif

The switch goes in between the cathodes of the battery and driver.

You don't need resistors unless you know what you are doing, repeat, you don't need resistors.

it's this driver:

http://www.dealextreme.com/details.dx/sku.10084

though from the pictures on the page, I only saw two wires coming out of it - how would I connect four?

edit: another thing - the switches have two main prongs on the two sides and one smaller one in the center - what are those for?

Your switch sounds like it's a single pole double throw. That means that the center prong will be connected to either one of the two outer prongs depending on the position of the switch. I would wire the battery to the center prong and then the driver to one of the outer prongs.

Your driver may come with documentation or surely someone here has experience with that particular driver.

Its designed for a flashlight, the rings on the bottom are for power in, central is + outside is -
If you don't need flashing modes a resistor drive off 3AA is perhaps a better/simpler option.

One wire to both outside prong, another to the centre prong. I've done it the way you said before, then you'd have to cycle through it 3 times, it gets old after a while.

Depends, some are on/on others are on/off/on with a center off position.
You probably want a cheap multimeter for this project.

Thanks for the replies - this is what I'm thinking so far (red and black are connected directly to the things, gray wire is just wire).

http://www.bikeforums.net/attachment...5&d=1223433748

Looks good. If you get this to work, I'm going to try it myself. I've been thinking about wiring a red cree led to a driver, witch, and 18650 inside a Dealextreme flashlight shell, in order to make a Dinotte-caliber taillight for Superflash prices.