Before the Raspberry Pi came out, one cheap and easy way to get GPIO on a computer with a real operating system was to manipulate the pins on an old parallel port, then most commonly used for printers ...
Easily connect your Sugar Valley (NeoPool, Hidrolife, Aquascenic, Bionet...) or compatible pool controller to Home Assistant via Modbus TCP. Full local control, real-time sensors, timers, relays, ...