send data over the 230 phase line :)

Nowadays you have internet comming out the wallplug, so I thought there must be a way to let an arduino talk to an other arduino over the 230V phase line.

As I only have 1 data line available it must be asynchronous. That is why I am thinking to use the Uart of arduino.

I want to connect the Tx pin of one arduino via a high pass filter directly to the fase. If I chose my components that I have cut-off frequency of about 100kHz the 50Hz tranfer is almost nothing, less than 1/1000. While the dataline has less than 6dB transfer loss. On the other side I want to connect the phase via the same high-pass filter to the Rx of an other arduino.

What I am unsure about is how to couple the arduino grounds to the null. I was thinking to use the same capacitors. Is that recommendable or what other components should I place in the black boxes?

I don't think it's that simple.

AC data communication

Google "power line modem" for a reliable way to send data over the AC line.

And be sure your last will and testament is up to date just in case that 230v mains doesn't play nice with you.

I already thought it would be a bit trickier than that :wink: I need to use the 50Hz as carrier wave and modulate it with the 115kHz information using amplitude shift keying.

From what I read on the internet I need to make use of a coupling transformer to get my information on the AC line. I also need to read the ASK part again in my telecom book and talk with my teacher ( ← knows alot about signal modulation). With AM the higher frequency is typically the carrier wave where the lower frequenty carries the information.

I got the basics real quick from this site: Loading...

I hope I can do it without the need of a special IC.

You can't modulate a 50Hz carrier with 115kHz! You are injecting a carrier at 115Hz, the 50Hz is
completely out of band and irrelevant to the communications other than it requires (safely) filtering out
before demodulating due to the large voltages. Even a single pole filter will perform well when the out
of band signal is 1/2000th of the frequency of your signal carrier.

You're assuming your power signal does not contain noise > 50Hz ...
Which I think is a pretty naive assumption. I think noise and high frequency signals generated by devices on your power network will probably be the greatest challenge ...