This tutorial shows how two things can communicated by NETPIE
Requirement : 1.Raspberry PI with nodejs, 2.4-channel relay
I have connected First relay with GPIO Pin 2, Second relay with GPIO Pin 3, Third relay with GPIO Pin 17 and Fourth relay with GPIO Pin 27
##Don't forget to install node modules with "npm install onoff microgear --save"
##You can get your APPID, KEYID and SECRETID from https://netpie.io