Re: Low spec 'scope.

Jan Panteltje <alien@comet.invalid> wrote:

On a sunny day (Thu, 29 Aug 2024 10:43:29 +0100) it happened
liz@poppyrecords.invalid.invalid (Liz Tuddenham) wrote in
<1qz1rr1.1p7aq3z13xmh1aN%liz@poppyrecords.invalid.invalid>:
 

If the Raspberry Pi could be made to fire itself up without any

 
AFAIK Raspi has no ADC input.
You will have to connect an ADC to the GPIO.
 
 

intervention and accept two analogue inputs, that would work.  (...but
someone would have to program it for me, or at least lead me through how
to program it.)  The 100Kc/s requirement isn't just fanciful
over-specification; this thing works on the signals that are well
outside the audio band and the 'scope needs to display them clearly,
despite all the audio clutter.  The H.F. signals are higher amplitude
than the audio but are in the nature of pulses and occur infrequently.
(The analogue scope has to be Z modulated from rate-of-change to
emphasise the pulses and avoid screen burn, but this wouldn't be a
problem with an LCD display.)

 
1 channel kit: < 7 US dollars:
 https://www.ebay.com/itm/295219906968
 I cannot even buy the parts here for that price.
  LCD 320x240 enough?

That would correspond to a screen 1.6" x 1.2" at 200 dpi, which would be
a bit too small.  I would regard 3" x 4" to be the optimum size. and 600
x 800 pixels to be the absolute minimum.  There is no need for colour.

 

Fast CD4053 or something CMOS switch makes 2 channels?
Trigger channel select from a CD4073 flopflop after each scan?
the possibilitiies are endless

I'm not trying to display 2 channels on 1.  I need an X-Y display so
that I can see the angle of contact of a stereo stylus with the
roughness of the groove wall and the pattern it traces as it plays the
modulation.

Knowing programming is almost a requirement these days (since the

seventies) in electronics.

I have programmed in Z80 machine code, Algol, Basic, Applescript, PHP
and HTML, but have only used the last two recently.  I also don't have
any programming tools as all my designs are analogue.

--
~ Liz Tuddenham ~
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www.poppyrecords.co.uk