Hello Butch.  A friend of mine made me an LED detector that emits a tone
when the nose of the device is placed over an LED or any light source for
that matter.  It runs on a 9V battery, and it works slick as snot.  I can
attempt to get the schematic, assuming that he actually drew one.  I believe
that all of the parts combined came to about $10.

Alan - N7MIT


Alan R. Downing
Phoenix, AZ

-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Butch Bussen
Sent: Monday, April 13, 2015 2:07 PM
To: [log in to unmask]
Subject: Re: light detector

Unfortunately I'm no good at soldering stuff like that.  Some one else 
mentioned a circuit using transisters.  I'd like to have that diagram, 
as I might be able to do that, although the only transister audio 
oscilators I recall used a center tapped audio transformer.
73
Butch
WA0VJR
Node 3148
Wallace, ks.


On Tue, 14 
Apr 2015, Dave Allen wrote:

> Hi Butch!
>
> Many thanks for the design and description.
>
> A couple years ago, I contacted the Blind Foundation's equipment shop and
> told them I wanted to buy a light probe. They had no idea what I was
talking
> about. I sourced one overseas, as that's what local incompetence generally
> promotes, hi hi.
>
> 73,
> Dave
>
>