Have you seen the responses to your other thread - on ALMOST the same topic?
Have you looked here: Learn→PV Diversion→Introduction ?
You can buy a hardware kit for Robin Emley’s Mk2 PV Diverter from his website mk2pvrouter.co.uk. You don’t need to use the measuring side, and the software for that is published there - so it’s completely free, both in accessibility and in cost - and you can modify it to accept control input, which is likely to be a digital input, serial or radio, from whatever you wish however you wish, subject of course to the limitations of the kit.
Or you could build your own, maybe with an Ethernet or Wi-Fi equipped Arduino and a commercial solid-state relay. If you do go down this route, make sure you get the SSR from a reputable supplier, as there are dangerous clones on sale.
