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Homeowner baffled after washing machine uses 3.6GB of internet data a day
(www.newsweek.com)
This is a most excellent place for technology news and articles.
I2C is very short range, it's meant for connecting parts on the same board. You want something like RS-485. The Modbus protocol, which runs over RS-485 would be perfect for this.
Yes, from quick googling seems exactly what I want.