Re: [Phys-l] led flashlights

[Bernard Cleyet <bernardcleyet@redshift.com>]

I'm posting this to PHYS/tap-L as others may be interested.

Chuck!

The removal of the arbor cover is new, Panzer, -- all the rest I've  
done.  50% duty won't maintain the same temp. because the power in  
more than doubles w/ doubling of the current.  However, it's not 4 X  
as expected from an ohmic device.  The diode, if it's a normal  
extrinsic, IIRC, will be exponential so 40% might do it.  I suspect  
intermittent operation, as I did! will be OK, but at $50 I hesitate.   
I have four of them (I rebelled at buying Best Buy * out, five of  
them -- this is my own $;  Gate Keeper puts a limit on subsidizing my  
experiments.)

The ubiquitous clip is, unfortunately Blu-Ray -- typical of Sony the  
construction allows much easier disassembly.  I haven't even found a  
non-destructive method of removal of the Toshiba) platform, not to  
mention the diode from the platform -- have you done it?

*One site advertises other sources also at $49.99

bc must interrupt and finish the French drains below the house eaves.

p.s. I did find a description of the PC XBox playing system.   
However, tho I have a no very old IBM platform, it doesn't appear  
worth my time to do it.  So if the diodes are useful I'l just remove  
them and save the optics, etc.  the detector may be interesting also.
p.p.s.  I'll additionally interleave -- duplicate to some readers.

On 2008, Mar 10, , at 06:32, chuck britton wrote:

> Thanks
>
>
> You can keep the disk securely in place by removing the white  
> plastic 'cap' that did so originally, from the metal lid of the  
> case. Peel back the yellow label.
> This cap has enough steel to firmly latch onto the arbor.
>
> We could see the blue light thru the disk. Also the red light  
> initially.

Yes, this initially encouraged, as the disk appears opaque when  
viewing w/ a lamp.

> If you flip the disk off of the arbor it will continue to shine  
> (and seek and try to focus) for a few seconds.
> A white sheet of  paper then shows the shape and size of the spot.

One may look directly "into" the beam and see the hour glass shape.

> You got a bright beam with 80 mA but worried about overheating.
> The pulsing idea would provide a 50%  duty cycle at 80mA without  
> overheating - but still making a bright (flickering) beam?

Considerable studies have been made on the luminosity of flickering  
sources.  I don't remember the results, but my impression is w/ a 50%  
duty cycle > ~ 15 Hz, it's continuous and the brightness is ~ to the  
average power.  This last is over a limited range, IIRC.  If anyone  
is interested I'll see IMMIC.  It should be in Levi's meta tome.
> On Mar 10, 2008, at 2:34 AM, Bernard Cleyet wrote:
>
> > Chuck!
> >
> > I haven't removed the LASER from the reader -- It appears to still  
> > work -- tho I must press lightly w/ two finger nails to keep the  
> > disk on the arbour 'till it's up to speed.  I soldered leads to  
> > the horizontal pins.  Can only see three, tho, likely a fourth  
> > bottom one.  o'scope doesn't reveal any pulsing.  I don't see any  
> > advantage in pulsing if only for pointer, etc use.
> >
> > bc
> >
> >
> > On 2008, Mar 08, , at 21:00, chuck britton wrote:
> >
> > > Bernie - could you / would you, share your pinout diagram of the  
> > > XBox laser modules?
> > > 3 pin and 5 pin IIRC.
> > >
> > > Some lasers are pulsed - fast enough to appear continuous.
> > > Maybe this blue one could be pulsed at 80 mA without damage?
> > > It seems to be mounted in a pretty chunky metal base/heat sink?
> > >
> > > I really want to make a blue pointer out of mine.
> > >
> > > On Mar 7, 2008, at 1:41 AM, Bernard Cleyet wrote:
> > >
> > > > Speaking of diode LASERs,  I purchased an XBOX 360 external HD DVD
> >
> > cut