Hi Phil

Possibly it was my message that you were going to reply to?

The reason I used to make light level indicators from bog standard NPN
devices was that for a blind guy they were easier to solder than the tenth
inch pitch of chips.

I seem to recall that there was a circuit around in the 70's using a ne556?
Possibly published by Smith-Kettlewell Foundation.

73

David W Wood 

-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Butch Bussen
Sent: Monday, April 13, 2015 1:21 AM
To: [log in to unmask]
Subject: light detector

I thought I kept the message I wanted to respond to, but I didn't. 
Anyhow, I wrote an article in qst way back in July of 1985 called the 
squawker.  It uses a 555 chip a couple resisters and a photo cell and 
almost anything for a speaker.  We actually used an old cassette recorder 
mlicrophone for the housing and the cartridge as the speaker.  I can put 
up the circuit if anyone wants it.  Will run on 5 volts, not sure how high 
the 555 will go, but I ran mine on a 9v battery.  If you put in a closed 
circuit phone jack as I did, it can become a continuity tester.
Pitch changes with brightness.
73
Butch
WA0VJR
Node 3148
Wallace, ks.