Can you please advice which Onion? and which interface kits? I require to control a USB Relay board with 8 relays (e.g. https://www.sainsmart.com/sainsmart-4-channel-5v-usb-relay-board-module-controller-for-automation-robotics.html)
Also, I prefer to have ethernet, if possible.
The reason I am looking into a USB relay board and not a direct connection, is because of this site that says it's dangerous to conect it directly? https://coderwall.com/p/izzsig/driving-a-sainsmart-relay-with-raspberry-pi
Is my assumption incorrect?
Thanks in advance!