We’re used to extending our network connections and being no longer constrained in our use of Ethernet by proximity to a switch or hub. Our houses routinely contain wireless networks, and of course powerline-Ethernet units passing data over our mains wiring. [Peter Franck] had a similar problem but without the mains power, for a distributed sprinkler system he needed to send Ethernet over DC cables.
The solution is a surprisingly simple one, taking one of those powerline Ethernet units and converting it by removing its mains power section. These devices contain the Ethernet and powerline modem chip with its associated circuitry, and a small switch-mode power supply. He’s removed the power supply and put in a capacitive coupling to the DC cabling, resulting in a relatively inexpensive DC powerline network device.
Powerline Ethernet devices are not without their own issues, for instance they are not popular with radio amateurs due to their effect on the RF noise floor. We’d therefore be curious to see what the RF emissions are like for this hack, but we still think it’s a useful weapon in the armoury as well as something to do with all those surplus powerline Ethernet bricks.