This is my take on monitoring Sonoff and other ESP8266 devices at home running the ESP Easy firmware in order to determine wifi signal issues, and outages. Spoiler alert, so far I was not able to draw any conclusions.
Node red flow: http://flows.nodered.org/flow/1963bdc5589a68c21ac7587ecc859612
Link to the ESP Easy forum topic mentioned: http://www.letscontrolit.com/forum/viewtopic.php?f=6&t=2623&start=10