I wanted to connect a rain sensor to my lawn irrigation controller, which was a simple dial system. There were two connections for the rain sensor, which appeared to simply disable the controller on/off abilities when rain is detected.
However, I wanted a wireless sensor and I wanted it connected to my on personal weather station rain gauge.
I went to the local electronics/DIY/maker store where it took some time for the experts to find an AC powered switch. The part itself was pretty cheap. The store clerk tested the unit for me and told me where to install the wires. After getting home, I simply soldered the wires for an AC plug and wire to the controller.
To make it work, I attached the controller and plugged my switch into a Wemo smart switch (which go on sale for as low as $30). Once all wired up, I connected my Wemo to IFTTT. My weather station was already IFTTT enabled, so simply needed to program the IFTTT routine...when rain was detected, disable the Wemo switch for 24 hours (the IFTTT program was a little tricky to figure out). And that was it!