Hi I’m trying to make a plugin for this 8-relay board available in the UK:
http://www.robot-electronics.co.uk/htm/eth_rly16tech.htm
It is IP-controlled, being connected by ethernet.
Would someone be able to suggest where I should start? The “IORelay” plugin by Guessed looks like a possibility, but on the complicated side, and I’m worried that it’s a couple of years old.
So far I managed to hack the on/off buttons on the plugin for the “Sharp Aquos TV” IP remote control so that they turned one of my relays on/off. Unfortunately though this plugin doesn’t seem to support being used in a scene - the scene doesn’t seem to remember pressing the buttons.
Controlling the relays is really simple, just sending a single byte to turn them on/off.
I’m hoping to control them from one of the Android apps, eg Vera Mobile (doesn’t seem to recognise my Everspring temp/humidity sensor, or the Virtual Switch), or Home Buddy (doesn’t seem to recognise my scenes)
I had managed to drive them from luup code in scenes, but I couldn’t see how to drive a scene from the other devices, eg Richard Schaefer’s plugins. I guess a proper plugin would be neater in that I should be able to see their states from vera (whereas the scenes just send the command and forget).
Incidentally they’re reasonably cheap, being about ?70 for 8 x 16A, mains voltage relays; this is cheaper than buying z-wave devices eg Fibaro light switch relays. Although the time burnt on wondering how to start on a plugin seems to have swallowed this advantage 
Looking forward to any advice.