Has anyone had issues with digital pins going high after/during device power shutdown? I have built a garage door opener using Blynk. It’s very simple. I simply have a Blynkapp button directly assigned to my D0 pin (that is initialized in setup as an output:
The pin is tied to the signal pin of relay 1 on a 2 relay module I got from Sunfounder. It works perfectly with output of the relay attached to the “close button” terminals of my opener. However if I pull the USB pwr plug on my Photon somehow the relay closes momentarily and my door will activate (and close or open). I got this project from Make magazine and to avoid this problem (they mentioned it but I ignored cause it makes no sense) they tie 2 digital output pins to the 2 relay modules in series. Somehow this strange behavior does not occur in all pins/relays at the same time.