Raspberry pi, python and robotics
bc at freeuk.com
Fri Sep 5 14:37:00 CEST 2014
"Gregory Ewing" <greg.ewing at canterbury.ac.nz> wrote in message
news:c6nv2hF8q6aU1 at mid.individual.net...
> Rob Gaddi wrote:
>> otherwise getting up and
>> running will cost you a solid $1200 just in gear.
> While having fancy gear certainly helps, it's not
> *strictly* necessary. When I first started dabbling
> in electronics, the most sophisticated piece of
> equipment I had was an analog multimeter.
> It got me through a lot of projects, including a
> couple of homebrew computers. It's surprising how
> much you can deduce about what's happening in a
> digital circuit by watching a needle bouncing
I also used LEDs (even showing complex signals, as they will dim in
different ways, or you could sometimes view them through a flipped mirror to
show the patterns).
Sometimes I fed a digital output to the video input of my TV (it was 5V to
1V, some care was needed), and the waveform became visible, although
unsynchronised to anything. With one line representing about 50us, you could
get a lot of clues about what was going on. (What I never tried with a TV,
because I later had a scope, was to arrange for the line-sync to trigger
some repeatable event I was trying to monitor. By using it as the /reset
signal of a microprocessor for example.)
Anyway, there were all sorts of tricks. I didn't have a proper knowledge of
(analogue) electronics either, just enough to get by, or picked up what I
needed as I went. (You tended to copy or adapt someone else's circuits.)
Besides, a normal non-storage oscilloscope wasn't directly useful for the
complex non-repeating signals you get with computer boards.
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