Hope im posting on the right place, if not please except my apology.
I am wondering if anyone can help me out please. I am just about to pull the last bit of my hair out now with a simply relay.
Here is what is currently been used : Single Wemos relay shield, Pcf8574 port expander and a esp8266.
I have done the following to test the pcf8574 uploaded a scanning utility to check the hex address of the pcf (0x20), configure a simple sketch to turn led's on and off the pcf8574. Now the problem is I cant trigger the relay on D1 which works fine connecting it to the Nodemcu. 5v to relay, ground to ground, D1 from nodemcu to D1 to the relay.
What am i doing wrong with the pcf. it turns a LEDS on and off why should it not trigger the relay aswell.