The $6 Luxeon flashlight

[zmoz]

Well...I was bored tonight so I thought I'd make use of the LS I got on ebay for 6 bucks. It was supposedly a "greeny" but mine appears pretty damn white. /ubbthreads/images/graemlins/smile.gif A few peices of duct tape later and we have this:

Beautiful ain't it? /ubbthreads/images/graemlins/grin.gif I'd say it works pretty darn good for 6 bucks. I had a spare 4AA holder from radio shack, filled one of the holes with foil, and am direct driving it with 3 NiMh. Under the LS is a peice of 1/8" steel for a heat sink. Lights up my entire garage...should run about 3 hours. I think I might make a more finished version of it now... /ubbthreads/images/graemlins/cool.gif

 

[Rothrandir]

/ubbthreads/images/graemlins/eek.gif

please find a better thermal conducter than steel!
3 nihm batteries on direct drive with aluminum heatsinks is bad enough!!

other than that, very nice! /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/grin.gif

 

[FalconFX]

Peltier!
/ubbthreads/images/graemlins/ooo.gif
/ubbthreads/images/graemlins/grin.gif

 

[Doug Owen]

[ QUOTE ]
Rothrandir said:
/ubbthreads/images/graemlins/eek.gif

please find a better thermal conducter than steel!
3 nihm batteries on direct drive with aluminum heatsinks is bad enough!!


[/ QUOTE ]

I'm not so sure steel is all that bad, assuming it's thick enough, but putting it flush against the battery pack (no air gap) and covering the other side with duct tape isn't helping...

Heatsinks aren't magic, the heat needs to go someplace else next or things get warmer.....

Doug Owen

 

[zmoz]

Well...as you can tell it's obviously not a permanent solution. /ubbthreads/images/graemlins/wink.gif

 

[Tree]

Is that one of those 4 AA holders from Radio Shack?

 

[zmoz]

[ QUOTE ]
Tree said:
Is that one of those 4 AA holders from Radio Shack?

[/ QUOTE ]

Yep.

 

[Darell]

It is a rare thing of beauty!

 

[hotbeam]

On the topic of cheap/querky/"very home made" Luxeon lights... take a look at this done sometime back.
The heatsink is finned and was obtained from a local electronics store... /ubbthreads/images/graemlins/rolleyes.gif

 

[zmoz]

[ QUOTE ]
hotbeam said:
On the topic of cheap/querky/"very home made" Luxeon lights... take a look at this done sometime back.
The heatsink is finned and was obtained from a local electronics store... /ubbthreads/images/graemlins/rolleyes.gif

[/ QUOTE ]

Beautiful. /ubbthreads/images/graemlins/wink.gif How is it running from what looks like two AAs and a resistor?

 

[hotbeam]

3 AAs and a resistor /ubbthreads/images/graemlins/smile.gif Sorry, should have taken the shot from a higher position.

 

[zmoz]

Damn...I wish you had a secret way of running it with only two and a resistor... /ubbthreads/images/graemlins/wink.gif

 

[hotbeam]

ahhh...... the secret voltage inverter circuit built into the resistor!!! /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/naughty.gif

 

[Rothrandir]

[ QUOTE ]
Doug Owen said:
[ QUOTE ]
Rothrandir said:
/ubbthreads/images/graemlins/eek.gif

please find a better thermal conducter than steel!
3 nihm batteries on direct drive with aluminum heatsinks is bad enough!!


[/ QUOTE ]

I'm not so sure steel is all that bad, assuming it's thick enough, but putting it flush against the battery pack (no air gap) and covering the other side with duct tape isn't helping...

Heatsinks aren't magic, the heat needs to go someplace else next or things get warmer.....

Doug Owen

[/ QUOTE ]

yes, steel is a decent conducter of heat, but not nearly as good as aluminum.
furthermore, he's overdriving it with 3 rechargable batteries...that is much worse than 3 alkalines.

 

[yclo]

You call that a heatsink!?

No resistors here. /ubbthreads/images/graemlins/grin.gif

 

[Ginseng]

Yikes! When you're not using it as a light, you can use it to slice tomatoes. /ubbthreads/images/graemlins/tongue.gif

Wilkey

 

[zmoz]

Got out the duct tape again...taped the light to my hat. /ubbthreads/images/graemlins/grin.gif Makes a GREAT headlight! /ubbthreads/images/graemlins/buttrock.gif

 

[Tree]

I just re-read the first post. Please ignore the stupid question in my previous post. /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/banghead.gif /ubbthreads/images/graemlins/jpshakehead.gif /ubbthreads/images/graemlins/jpshakehead.gif /ubbthreads/images/graemlins/jpshakehead.gif

My attention to detail is sometimes lacking. /ubbthreads/images/graemlins/blush.gif

 

[Doug Owen]

[ QUOTE ]
Rothrandir said:

yes, steel is a decent conductor of heat, but not nearly as good as aluminum.
furthermore, he's overdriving it with 3 rechargeable batteries...that is much worse than 3 alkalines.

[/ QUOTE ]

I agree that steel is not as good as Al (I'm not so sure I'll buy 'not nearly as good') but it's far better than nothing (which the Luxeon will survive under the proper conditions, provided it's not wrapped up in insulation...).

However, I cannot agree that NiMH direct drive is "much worse than alkalines". The differences in internal resistances are minor (despite what popular opinion is here, go look it up), say 40 against 150 miliohms per cell from the Duracell specs. Assuming 1 ohm in the Luxeon makes the NiMH 3.6 Volts less 3.4 (mid range J bin) divided by 1.16 ohms 171 mA. For alkaline we have 4.5 less 3.4 divided by 1.6 ohms, 688 mA, nearly four times.

Even assuming a not so realistic 3.0 Vf, we get 517 mA for NiMH, 938 for alkaline. For sure things drop off for the alkaline version quickly as the cells age, but it's the first bit that destroys the LED.

Or so the number seem to say. And that's what happens when I try it.

Have you done the math or tired it?

Doug Owen

 

[Rothrandir]

what i'm saying, is that most people wouldn't be brave enought to try it with a good aluminum heatsink. steel isn't as good as aluminum.
furthermore, from the picture, i'm not able to determine the extent of his heatsinking.

needless to say, it's a nice little light /ubbthreads/images/graemlins/grin.gif