I just want to show, how you can use Opensprinkler with a Raspberry Pi which is currently in use on another service and valves cannot be connected directly to the Raspberry Pi.
My RP is in use for my door ring. My sprinkler valves are on another location outside in the garden.
In this case I´ve took a NodeMCU which is based on a ESP8266, searched a tutorial for a webswitch and added a few outputs (check attached screenshot). This souce code is attached below and can be used and customized.
Wifi SSID and PW must be changed to your own.
On the NodeMCU I connect 4 relais which are connected on Pin Valve 1 (D4), Valve 2 (D5), Valve 3 (D6), Valve 4 (D7) also VCC and GND.
After that i go to OpenSprinkler UI and change the station type to HTTP (check attached screenshot). Enter following fields:
-Servername: internal IP-Adress of the NodeMCU