Question

I’m not interested in a hardware solution, I want to know about software that may “read” modulated signal received trough the power supply – some sort of a low-level driver that would access the power signal in a convenient place and demodulate it.

Is there a way to receive signal from the computer’s power supply? I’m interested in an API or library that would allow the computer to be seen as a node in a Power Line Communication network and receive data directly through the power cable, without the need for a converter. Is there any active research in this field?

Edit:

There is software that reads monitors and displays internal component voltages – DC voltage after being converted and filtered by the power supply – now I need is a method of data encoding that would be invariant to conversion and filtering, the original signal embedded in AC being present in some form within the converted DC signal.

Answer 1

This is highly improbable without adding some hardware.

You see, the power supplies in a regular PC are switching power supplies which effectively decouple the AC input from the supplied DC voltage needed on the PC side. The AC side just basically provides power that fuels the high-speed power switching circuitry.

Also, a DC signal, by definition, doesn’t provide a signal per se: it is a “static” power level (and yes the power level does vary a bit in the time domain but not as an easy to leverage function).

Yes there can be an AD (Analog to Digital) monitoring chip that can be used on the PC side to read the voltage of the DC component supplied to the motherboard etc., but that doesn’t mean there is still a signal that can be harvested: the original power line “signal” might have been through enough filters that there isn’t a “signal” left to be processed.

Lastly, one needs to consider that power supplies design varies from company to company; this fact will undoubtedly affect any possible design of a communication solution.