Re: Water heater eating X-10 signal

[nobody@xxxxxxxxxxxx (Dave Houston)]

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. ;)