SCR info needed for sound activated light Morse Code

I need to transform audio morse code into flashing light morse code.

My goal is to drive a light bulb to flash morse code from an audio speaker
level source output. (cassette player).

My grasp of the use of SCR's is very limited, but I was thinking of using a
12.6v
filament transformer in series with an SCR and a light bulb, then use the
audio output (external speaker) from a small cassette player to drive the
gate of the SCR. I am assuming the gate will detect the audio and drive the
scr junction into conduction to light the bulb visually displaying the dots
and dashes as flashing light.
What general use SCR available at Radio Shack might work in this
application.

Any help appreciated.

thanks,

Vin Collins

On Wed, 22 Feb 2006 21:31:57 GMT, "Vin Collins" <(E-Mail Removed)>
wrote:

>I need to transform audio morse code into flashing light morse code.
>
>My goal is to drive a light bulb to flash morse code from an audio speaker
>level source output. (cassette player).
>
>My grasp of the use of SCR's is very limited, but I was thinking of using a
>12.6v
>filament transformer in series with an SCR and a light bulb, then use the
>audio output (external speaker) from a small cassette player to drive the
>gate of the SCR. I am assuming the gate will detect the audio and drive the
>scr junction into conduction to light the bulb visually displaying the dots
>and dashes as flashing light.
>What general use SCR available at Radio Shack might work in this
>application.

---
Excellent description of what you want to do, and I can't see any
reason why it won't work, but I'd go for a TRIAC instead of an SCR
in order to get both halves of the 60Hz to drive the lamp.

Unfortunately, I can't help you with what RS has in stock, since a
search for "TRIAC" on their site goes basically nowhere.

The good news is you should be able to use pretty much any TRIAC you
can find as long as it can handle the lamp current and your cassette
player can supply the current to turn it on.

The bad news is...
Oh, wait... there isn't any bad news.

Your filament transformer will provide isolation from the mains, and
as long as your cassette player's got the guts and the TRIAC can be
fired in all four quadrants, you're home, free.

:-)

--
John Fields
Professional Circuit Designer

Vin Collins wrote:
> I need to transform audio morse code into flashing light morse code.
>
> My goal is to drive a light bulb to flash morse code from an audio speaker
> level source output. (cassette player).
>
> My grasp of the use of SCR's is very limited, but I was thinking of using a
> 12.6v
> filament transformer in series with an SCR and a light bulb, then use the
> audio output (external speaker) from a small cassette player to drive the
> gate of the SCR. I am assuming the gate will detect the audio and drive the
> scr junction into conduction to light the bulb visually displaying the dots
> and dashes as flashing light.
> What general use SCR available at Radio Shack might work in this
> application.
>
> Any help appreciated.
>
> thanks,
>
> Vin Collins
>
>
Look for a VOX circuit, normally used for such functions as operating a
transmitter PTT upon audio being present. Use it's output instead to
drive a relay (solid-state or not) and then a light bulb.

Here's a starter, but by no means the only circuit around:
http://www.rason.org/Projects/basicvox/basicvox.htm

Cheers.

Ken

On Wed, 22 Feb 2006 16:29:42 -0600 in sci.electronics.basics, John
Fields <(E-Mail Removed)> wrote,
>Excellent description of what you want to do, and I can't see any
>reason why it won't work, but I'd go for a TRIAC instead of an SCR
>in order to get both halves of the 60Hz to drive the lamp.
>
>Unfortunately, I can't help you with what RS has in stock, since a
>search for "TRIAC" on their site goes basically nowhere.

Radio Shack has some Solid State Relay modules that I'd prefer for
the isolation.

On Thu, 23 Feb 2006 12:39:05 +1300, Ken Taylor
<(E-Mail Removed)> wrote:


>Look for a VOX circuit, normally used for such functions as operating a
>transmitter PTT upon audio being present. Use it's output instead to
>drive a relay (solid-state or not) and then a light bulb.
>
>Here's a starter, but by no means the only circuit around:
>http://www.rason.org/Projects/basicvox/basicvox.htm

---
The problem with that, and most other VOX circuits, is that they
decay too slowly and, consequently, dah-di-dah gets smeared into
dahhhhhhhhhh.

--
John Fields
Professional Circuit Designer

On Thu, 23 Feb 2006 06:42:26 GMT, David Harmon <(E-Mail Removed)>
wrote:

>On Wed, 22 Feb 2006 16:29:42 -0600 in sci.electronics.basics, John
>Fields <(E-Mail Removed)> wrote,
>>Excellent description of what you want to do, and I can't see any
>>reason why it won't work, but I'd go for a TRIAC instead of an SCR
>>in order to get both halves of the 60Hz to drive the lamp.
>>
>>Unfortunately, I can't help you with what RS has in stock, since a
>>search for "TRIAC" on their site goes basically nowhere.
>
>Radio Shack has some Solid State Relay modules that I'd prefer for
>the isolation.

---
Since he'll be using a filament transformer to drive the lamp he'll
already have adequate isolation from the mains, plus there's (maybe)
the issue of driving the relay with AC.

In any case, I went to their site and couldn't find any solid-state
relays. Got a link?


--
John Fields
Professional Circuit Designer

John Fields <(E-Mail Removed)> wrote in sci.electronics.design:
> On Thu, 23 Feb 2006 12:39:05 +1300, Ken Taylor
> <(E-Mail Removed)> wrote:
>
>
> >Look for a VOX circuit, normally used for such functions as operating a
> >transmitter PTT upon audio being present. Use it's output instead to
> >drive a relay (solid-state or not) and then a light bulb.
> >
> >Here's a starter, but by no means the only circuit around:
> >http://www.rason.org/Projects/basicvox/basicvox.htm
>
> ---
> The problem with that, and most other VOX circuits, is that they
> decay too slowly and, consequently, dah-di-dah gets smeared into
> dahhhhhhhhhh.

Even if it didn't, if the audible signal is anywhere near typical
morse speed, the eye won't be able to follow. Optical morse signalling
is *much* slower than acoustic.

Anno
--
If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers.

John,

Thanks for your input, I was fairly certain I could do it this way. I looked
into VOX ckts and comparators etc,,,
Sometimes really simple ckts are best, and for a simplton such as myself
simple is about the only way to go.

BTW: This project is so I can prepare for a US Coast Guard flashing light
exam. Flashing light requirement for the exam is around 6 WPM.

Thanks again,

Vin Collins


"John Fields" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> On Wed, 22 Feb 2006 21:31:57 GMT, "Vin Collins" <(E-Mail Removed)>
> wrote:
>
>>I need to transform audio morse code into flashing light morse code.
>>
>>My goal is to drive a light bulb to flash morse code from an audio speaker
>>level source output. (cassette player).
>>
>>My grasp of the use of SCR's is very limited, but I was thinking of using
>>a
>>12.6v
>>filament transformer in series with an SCR and a light bulb, then use
>>the
>>audio output (external speaker) from a small cassette player to drive the
>>gate of the SCR. I am assuming the gate will detect the audio and drive
>>the
>>scr junction into conduction to light the bulb visually displaying the
>>dots
>>and dashes as flashing light.
>>What general use SCR available at Radio Shack might work in this
>>application.
>
> ---
> Excellent description of what you want to do, and I can't see any
> reason why it won't work, but I'd go for a TRIAC instead of an SCR
> in order to get both halves of the 60Hz to drive the lamp.
>
> Unfortunately, I can't help you with what RS has in stock, since a
> search for "TRIAC" on their site goes basically nowhere.
>
> The good news is you should be able to use pretty much any TRIAC you
> can find as long as it can handle the lamp current and your cassette
> player can supply the current to turn it on.
>
> The bad news is...
> Oh, wait... there isn't any bad news.
>
> Your filament transformer will provide isolation from the mains, and
> as long as your cassette player's got the guts and the TRIAC can be
> fired in all four quadrants, you're home, free.
>
> :-)
>
> --
> John Fields
> Professional Circuit Designer

Vin Collins wrote:
> I need to transform audio morse code into flashing light morse code.
>
> My goal is to drive a light bulb to flash morse code from an audio speaker
> level source output. (cassette player).

If you were able to use an LED as the flasher, things could become
*much* less complicated...

--
St. John
Your analyst has you mixed up with another patient. Don't believe a
thing he tells you.

On Thu, 23 Feb 2006 06:35:51 -0600 in sci.electronics.basics, John
Fields <(E-Mail Removed)> wrote,
>Since he'll be using a filament transformer to drive the lamp he'll
>already have adequate isolation from the mains, plus there's (maybe)
>the issue of driving the relay with AC.

You're right.

>In any case, I went to their site and couldn't find any solid-state
>relays. Got a link?

I saw them in bubble packs hanging from a hook. But maybe that was
too far in the past. I couldn't find links to the triacs or SCRs
either.