[Laser] off topic

[riese-k3djc at juno.com]

I was looking to mount several of the H Power diodes on /in a piece of
PVC
and fix that to the handle bar,, I need a wide band of light with lots of
spill
over so reusing an existing head lamp housing,, which I dont have ,, isnt
going to work. With my night vision not so great just a bright spot
on the trail is exhausting to use,, with the NMHD and better batteries
at good prices i figure several hours if use should be avaible so I need
a wide
spill of light
 
Bob K3DJC
On Mon, 2 Jun 2008 13:51:18 -0500 "James Whitfield" <n5gui at cox.net>
writes:
> Bob
> 
> You did not say if you were trying to mount an LED ( presumably a 1 
> Watt or
> 3 Watt version ) in a standard bicycle headlamp fixture, or if you 
> are
> "starting sorta' from scratch".
> 
> If you are trying to put an LED into an existing fixture that will 
> take a
> standard size flashlight bulb, then you might look into the 
> "replacement"
> versions that are sold in hardware stores.  That may just drop in.
> 
> If you can tolerate a rather mechanically awkward solution, mount a
> three-"C" or three-"D" cell flashlight, such as the Mag-Lite, which 
> has an
> adjustable focus by twisting the head.  The reflector in the head is 
> a
> paraboloid which will focus parallel rays to a point, or conversly 
> direct
> rays from a point source into parallel rays ( seen as a "spot" ).  
> The
> filiment of a flashlight bulb is usually smaller than an LED 
> emitter, thus
> closer to a point source, and therefore procduces a tighter spot of 
> light.
> By moving the source forward or aft of the focus, the minimum spot 
> size gets
> bigger.
> 
> This may be closer to what you have in mind for a bicycle headlamp:  
> I have
> tried to mount an LED from a string of Christmas Tree lights in the 
> focus of
> a 6V lantern flashlight.  The LEDs that I am using have a inverted 
> conical
> tip to make a more spherical pattern than other LEDs.  What you 
> might try is
> mounting the high power LED just aft of the focus.  You probably 
> will have
> to cut off the back of the reflector because the hole for a 
> flashlight bulb
> isn't big enough.  The reflector was designed for flashlight bulbs 
> with the
> filament ( point source ) forward and having some light emitted at 
> a
> rearward angle.  That "rearward" part of the reflector can be cut 
> off if
> necessary to accomodate the larger LED assembly, which will emit 
> only
> forward.
> 
> Let us know how your project works out.  It seems like it might be
> applicable to "searchlight" beam for light communication.  Maybe not 
> so far
> off topic as you think.
> 
> James
>  n5gui
> ----- Original Message -----
> From: <riese-k3djc at juno.com>
> To: <Laser at mailman.qth.net>
> Sent: Monday, June 02, 2008 11:27 AM
> Subject: [Laser] off topic
> 
> 
> > any thoughts on how to use the higher powered leds as a bike 
> headlamp
> > would like to be able to broaden the ilumination to make it less 
> of a
> > spot light
> >
> > bob k3djc
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