Dorcy 4AA conversion, step-up dimmer LED light

[jeff1500]

Here's an LED conversion with a dimmer.

http://edusite10.tripod.com/led3/max757/max757.html

It has 4 leds, 2AA batteries and a Max757 step-up circuit.

Nice diffuse light.
Lights up dim for use in the middle of the night.
Fits in a jacket pocket.
Parallel leds (not the best, but okay)
Regulates voltage.
Uses Nimh or alkaline batteries.
Big parts for easy assembly.

[lambda]

jeff1500,

Nice mod; I like the dimmer function. Not too many projects include 'extra' functions like that. This would make a handy all purpose light without breaking the bank in the process.

Good work!

And thanks for keeping the info up on your web site for everyone.

[Daniel Ramsey]

Sell it, its a doggone good idea! [img]images/icons/smile.gif[/img]

[jeff1500]

I just added a beam photo.

http://edusite10.tripod.com/led3/max757/max757.html

I really like this light. I'm kind of driving it. I keep adjusting the brightness as I walk around with it to get just the right intensity.

I'm starting to think that a flashlight without a dimmer is like a car without a gas pedal.

[lambda]

That's a nice looking beam, and I like your targets.

Constantly adjusting the brightness eh? Sounds like an afliction connected somehow to the desire to illuminate things in the perfect light.

Have to try this mod and see if it affects me in the same way.......

Seriously, I've got the perfect light; it's a Dorcy Boss 4AA light. And of all things, my wife bought it at the Dollar store for me for $3.00 with batteries. I think she's getting the light bug too. [img]images/icons/smile.gif[/img]

[remuen]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jeff1500:

I'm starting to think that a flashlight without a dimmer is like a car without a gas pedal.<HR></BLOCKQUOTE>

Good job, Jeff! One argument more for using a DC-DC converter.

Btw, the LT1932 chip has a build in dimming control function. Could be of interest for you to modify some smaller flashlights.

[jeff1500]

Now that I've got it working with big pieces, I'll probably start thinking about making things smaller with surface mount parts.

One of these days I want to try to solder a small chip to a SurfBoard adapter.

And I also wonder if two chips can be hooked up in parallel for higher current flows?

[lambda]

Yes, two chips can be hooked together under the right conditions. If the output of both pass thru diodes, then there would be no feedback. I've done it with two Motorola MC34063 chips without any problems; though it didn't deliver 'twice' the current, it did significantly increase it; though that may have been because of the weak batteries I was using at the time.

[jeff1500]

I made a couple more modifications just to see what would happen.

1. I ground the leds flat and polished them with toothpaste. Big change in light pattern. No more hot spot. Now it's really even light like a fluorescent bulb.

2. I made a filter out of a piece of plastic from a paint tray liner (49 cents at Walmart) It's almost clear but it has a green tint. The light is still white but now it's much softer.

Here's an interesting web site about color theory:

http://www.beer.org/~tpark/color.html