Data on DC power lines?

[boroko]

Hi All,

I have been lurking and absorbing much from all who contribute... Thanks to All.

I have an ap that would require sending commands over the low voltage (existing) power lines.

I have seen it done on some commercial control systems, but couldn't get access to the guts to see how it was done.

Has anyone else seen this done?

Just to make this appropriate, the destination is a 16f628 and the comm is one way.

I have been toying with using the comparator across a shunt on the power line and a healthy cap to hold the micro on while the data comes through.

Thanks
Bo

[Archangel]

Hi boroko,
It is not uncommon to send power and r/f through a common line, each end of the wire has a choke and capacitor attached. The d/c goes through the chokes and the A/C goes through the caps, though I do not think you can send serial data that way unless you first convert it to HF radio type signal. Heck, give it a try, what's the worst case scenario, fry a 3 dollar chip ?

[PJALM]

Yes this is possible but requires you to use an RF modulator to send the data and a RF demodulator to decode it. This is not something you want to attempt unless its absolutely required. These methods are not aproved by the FCC for Commercial use without licensing.

If you still want to attempt it lookup X10, it uses a simular technique but for AC power and there are examples for picbasic.