Re: Water heater eating X-10 signal

[lnh <lnoh@xxxxxxxxxxxx>]

In article <lnoh-5DB9DB.00020603052007@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
 lnh <lnoh@xxxxxxxxxxxx> wrote:

> In article <463877f0.83255828@xxxxxxxxxxxxx>,
>  nobody@xxxxxxxxxxxx (Dave Houston) wrote:
>
> > lnh <lnoh@xxxxxxxxxxxx> wrote:
> >
> > >> Appendix C, FIGURE C-3 (within dashed line rectangle)...
> > >>
> > >>      http://ww1.microchip.com/downloads/en/AppNotes/00236a.pdf
> > >
> > >Off to the parts house. Thanks.
> >
> > While there, grab a 25VAC wall transformer if you're interested in recording
> > lengthy sequences with a soundcard. It will provide isolation while getting
> > the line voltage down to a level that's safe for humanoids before devising a
> > circuit to make the 60Kz and 120kHz levels safe for the soundcard.
> >
> > Alternately, you can open up your ESM1 and use it as the source for input to
> > a soundcard. John Galvin reverse engineered a schematic for the ESM1 shortly
> > after it was introduced.
> >
> >      http://home.pacbell.net/lgalvin/esm1.gif
> >
> > This is so obvious that I should have thought of it years ago as the need
> > for lengthy PLC captures arises frequently. (In my defense, I usually use my
> > DSO 'scope.) Recording them as .WAV files allows for editing and analysis in
> > a Wave editor (e.g. Goldwave) with the length only limited by disk space.
> > Tapping into the ESM1 really simplifies things. You can get 60Hz on PIC pin
> > 13 and the signal on PIC pin 18, it's isolated and all low voltage. If I
> > were ELK, I'd add a 1/8" stereo jack and a few resistors and double the
> > price. ;)
>
> Interesting. I would have thought the wall wart would attenuate the high
> frequencies we were looking for.
>
> By the way, I built the scope circuit in the AppNote above. It seems to
> work, although I won't be able to test it until tomorrow. I also built
> in the 32KHz high pass from the AppNote to play with.
>
> Thanks again to all.

Well, it works. And works well. I found a bad battery backup and a bad
GFCI outlet. It took a lot of breaker flipping, but watching the change
in noise and signal levels was very helpful. One by one the changes made
by bringing a new circuit on line could be monitored visually. Very
helpful.

Thanks.