Re: Low spec 'scope.

Jan Panteltje <alien@comet.invalid> wrote:

On a sunny day (Wed, 28 Aug 2024 08:39:25 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qyzrl3.ocj6lm4e4yaN%liz@poppyrecords.invalid.invalid>:
 

The recent thread on high-end oscilloscopes has reminded me of a project
that I shelved some years ago and might be due for resurrection:  I am
looking for a real-time display about 3" x 4" that can behave as an X-Y
oscilloscope with a bandwidth of about 100 Kc/s; a flat panel would be
ideal.
>
Currently I am using an actual X-Y oscillocsope to monitor the output
from a stereo gramophone cartridge, which allows me to check historic
discs for damage or faulty recording geometry.  The tube is about 14"
long, which means it has to be a standalone shelf unit and I can't build
anything like it into portable equipment.
>
I've not come across anything like this, but I'm sure such things either
exist or can be made by adapting something that is readily available.  I
have never been down the digital route, so anything that would need a lot
of programming from scratch will never get built.

This was an experiment:
 https://panteltje.nl/panteltje/pic/scope_pic/
works for audio, has spectral display too,
can also send screendump as text file to Usenet.
Control via RS232 or some buttons if you can code.

Thanks very much for that.  It has most of the reatures I need and the
sampling rate is just about adequate.  It 'remembers' its last settings,
which is essential for this application.

I have coded in the past but it was a most frustrating exercise and
something I would like to avoid if possible.  Also, I don't have any way
of connecting to the chip and uploading the code.

 

Cost? Maybe the LCD is the most expensive part, 5 dollars?

Very reasonable

Display has low resolution, so I did a shift right a couple of times to
divide the output. A better display will give better resolution.

The detail is extemenly important in this application - the minimum
resolution being 200 dpi.

There are plenty of single chip cheap digital scopes on ebay.
 https://www.ebay.nl/itm/315279795435
  have not tried that one :-)

I'll have to work through them and see which ones can be used as X-Y
scopes, with good enough resolution and the ability to start fully
functional from power-up.

Failing that, I have an oscilloscope tube and driver chassis, so I could
mount it horizontally in the bottom of the box with a 45-degree mirror,
so I can look down on it through a hole in the horizontal control panel.


--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk