Go green, Convert your old TV to an Oscilloscope: Plans $2.

[Christopher]

..
To be donated to a local kids museum for an audio visual affect!

This sounds silly but with all these 32" televisions getting dumped I
wanted to convert one to generate a real time display of the rough
waveform of music or voice on the screen.

I have seen several approaches but they ruin the integrity and safety
of the television in use. Taking advantage of the three independent
red, green, blue CRT guns would also be a nice.


I would like to find a circuit board layout or finished product I can
use to input Audio through the Video jack to display waveforms on an
analog TV screen.


Thank you all,

* * * *

Christopher

Temecula CA.USA
http://www.oldtemecula.com

 

[Jasen Betts]

On 2009-02-11, Christopher <christopher@NOSPAMoldtemecula.com> wrote:

.
To be donated to a local kids museum for an audio visual affect!

This sounds silly but with all these 32" televisions getting dumped I
wanted to convert one to generate a real time display of the rough
waveform of music or voice on the screen.

I have seen several approaches but they ruin the integrity and safety
of the television in use. Taking advantage of the three independent
red, green, blue CRT guns would also be a nice.


I would like to find a circuit board layout or finished product I can
use to input Audio through the Video jack to display waveforms on an
analog TV screen.


Thank you all,

input
||
computer with audio input and composite video output running free scope software
||
used TV


what makes you think the museum wants to maintain
cobbled-together hardware?

 

[Christopher]

On 17 Feb 2009 10:57:55 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

input
||
computer with audio input and composite video output running free scope software
||
used TV


what makes you think the museum wants to maintain
cobbled-together hardware?

Hello Jason,


I really enjoy your many posts at SEB. The original theme of the kids
museum is cobbled together "artistic" electronics.

Visit my photos here:

http://www.oldtemecula.com/pennypickle2/


The problem I see when I visit is, there is nothing interactive!!!

It has the correct idea of capturing the curiosity of kids using the
"Wow" affect which hopefully will ignite a spark in the next
generation of engineers and scientists. They have become a lost
generation here in the USA.

The simplest approach I have come up with for the oscilloscope idea is
the change the vertical yoke connections to the horizonal and then
drive the vertical coil connections with an audio amplifier that has a
18 volt or more voltage swing.

The kids would access this oscilloscope by using a wireless microphone
to yell in for a visual affect, plus this keeps it safe.

My main project in development for the Museum is a concept that uses
the theremin, a musical instrument, to create a nice audio/visual
affect.

All of my projects are donated and now that I am retired I might spend
more time searching and finding inspirational ideas for the museum to
motivate today's youth, if only one!

* * * *

Christopher

Temecula CA.USA
http://www.oldtemecula.com

 

[Jasen Betts]

On 2009-02-18, Christopher <christopher@oldtemecula.com> wrote:

On 17 Feb 2009 10:57:55 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

input
||
computer with audio input and composite video output running free scope software
||
used TV

there exist on the web microcontroller projects that provide an
audio-frequency capable oscilloscope function with a TV compatible
output

first cab off the rank:
http://www.jandspromotions.com/philips2005/Winners/AR1755.htm

another advantage with not modifying the tv is that should it fail
the scope can be connected to a different TV.

what makes you think the museum wants to maintain
cobbled-together hardware?

I really enjoy your many posts at SEB. The original theme of the kids
museum is cobbled together "artistic" electronics.

ah! I was woried you may have been setting yourself up for a dissapointment.

Visit my photos here:

http://www.oldtemecula.com/pennypickle2/


The problem I see when I visit is, there is nothing interactive!!!

does the typewriter (glass teletype?) not work?
perhaps you could put "eliza" or some other AI simulator on the other
end? (or even a cell modem to send/receive SMS - if you can get a
favourable deal)

I like the "long life" remote control.

It has the correct idea of capturing the curiosity of kids using the
"Wow" affect which hopefully will ignite a spark in the next
generation of engineers and scientists. They have become a lost
generation here in the USA.

for somethings simple that's interactive hook a microwave oven
turntable motor up to a bunch of neon indicators.
(or even to a bridge rectifier and a "galloping neons" circuit)

The simplest approach I have come up with for the oscilloscope idea is
the change the vertical yoke connections to the horizonal and then
drive the vertical coil connections with an audio amplifier that has a
18 volt or more voltage swing.

the vertical and horzontal yoke windings may have different
inductances, you could try turning the TV on it's side, it'd not look
out of place.

alternatively you could try this:

horizontal ---|\
| >---> red
audio 1 ---|/

horizontal ---|\
| >---> green
audio 2 ---|/

horizontal ---|\
| >---> blue
audio 3 ---|/

and turn the set sideways again.

the "horizontal" inout should be proportional to the current in the
in the yoke, there will probably be a place somewhere in the
set you can get that from, or use a hall-efect sensor on the yoke.

to get lines instead of a "landscape" use one-shot monostables after
the comparitors.

perhaps provide musical instruments that make nice waveforms too.

a plastic speaking tube provides as much isolation as a wireless mic,
and seems more in keeping with the spirit of the exhibit.