My First Light - Controller?

Hey all.

I've been reading around here for a while and have decided to join up and ask a few questions of my own. I'm a mechanical engineering student with not too much knowledge of circuits, yet. Anyway, im looking to build my own light from the ground up. I've decided on the cree Q5 as my emitter:

http://www.dealextreme.com/details.dx/sku.2394

My questions start here. I'd like to keep the light as cheap as possible (being my first and all). I'm trying to package this all in a pretty small light, but want some serious output. I'd like to use 123a batteries, or simply AA. Here are my questions, give these power options, what controllers should I look at. It sounds like with good heat sinking, I'll be able to run them at 1.0A. I looked at the buckpuck, but it seems to me that there are simpler, cheaper options if I don't need the modes.

2 AA batteries (for a total of 3.0V, correct?)

or

1 123a battery (3.0V)

I would also be open to the idea of using 2 123a batteries if that's better. I'd like to be able to match the output of a fenix T1 Tactical.

Thanks much, forgive my ignorance. I'll keep you updated on the progress, as I intend to design and manufacture the entire body.

A 123a primary cell is 3.0 volts. There are 3.6v rechargeable cells that are a bit exotic and you might want to keep things simple at first.

If you're really trying to get the output of a T1 you should use two cells. Your main problem will be thermal management.

You might get a book like Horowitz and Hill's "Modern Art of Electronics" to learn some practical stuff about circuits. Maybe by now it should be called "Ancient art of electronics" since it's an older book, but it still explains the basics better than anything else I've seen.

Thanks for the input! So, would running 2 123as and a Q5 be a good choice then, for a simple, first light? What type of controller would you suggest?

Two 123a's and a q5 is about the best you can do for a powerful 1-led light. The next step after that is multiple leds. When you say "controller" that sounds like dimmers and flashers, but the first thing you need is voltage/current regulation. If you don't want to build your own, I'd say try the Downboy series from the Sandwich Shoppe (see the Shoppe forum here on CPF).

Welcome to CPF by the way. Do you mind if I ask how you found us?

Thanks! To be honest, I just stumbled upon it while searching google for the answer to a question I had. After reading the answer, I stayed around a while and realized this is just the resource I've been looking for. 5 months later, I joined, haha.

I'll take a look at the downboy series. I suppose I should have chosen my words more carefully, as I'm not looking for a dimmer, etc. Thanks again.

EDIT: Well, it sounds like 2 123as is the way to go. I'm look at the shoppe and it looks as though they've got one type of downboy board. So, if I'm running 6.0V from the batteries, am I look for a board that can take an input of 6V and still allow the LED to draw 1000mA?

It might be easier to buy a light that will do what you want, but what's the fun in that?

The Son Of Buck 1000 might be what you are looking for(I've also seen one post where someone got 1 amp at the LED with a 1 AA NiMh Battery and a special board).

With a Cree XR-E Q5 at 1 amp, you should be getting around 230 lumen at the LED.

Also, what are you going to place everything into?

:welcome:

You probably want to use this board:
http://theledguy.chainreactionweb.com/product_info.php?cPath=48_49_61&products_id=1006

The output on this one is 917ma, which is close enough to 1amp. I wouldn't bother switching out the one resistor to get to 1 amp.

You don't want the minimum input voltage to be 6 volts, because as your batteries run, the voltage drops.

Thanks for the tips.

Gunner, I plan on making my own housing, tailcap and light assembly. That's the main part of the build for me. Here, I'm really just trying to get the internals that will make it a well functioning light.

Gmoney, thanks for the advice on the board. Are there any less expensive alternative? $20 isn't much, but it will be if I mess up the soldering or something.

I've decided that in addition to the cree xr-e Q5, I'm going to use this clicky switch:

http://www.dealextreme.com/details.dx/sku.5632


I've been looking at the cree xr-e lens that cutter offers. Any thoughts? Would it be better to go with a reflector? If so, any suggestions?
http://www.cutter.com.au/prodimages/creexreoptic.gif

Thanks again for all the help, I'll keep you updated.

TickTack said:

I've been looking at the cree xr-e lens that cutter offers. Any thoughts? Would it be better to go with a reflector? If so, any suggestions?

Click to expand...

Thought: They are less expensive at KD. They also have reflectors, which would give a bit more spill.