Hi E - GREAT FIND on that video, indeed very helpful, thanks so much! However, I started to wire up a test and realized my board does not have a "JD-VCC specific GND" like his board. I would assume I wouldn't use the GND next to VCC as it likely breaks the isolation? See the differences below for what I mean.

 

After some more digging, I found another manufacturer making what looks like the same board, and from this diagram I am assuming that the J2 jumper may be for the GND.

 

ALRIGHT! That was it, it is working as expected now. I appreciate your patience and help E, thank you!

Arduino Sketch Testing Code (if anyone else needs it):

#define relayPin 14 //D5 on ESP8266

void setup() {
  digitalWrite(relayPin, HIGH); //This prevents current from flowing into this pin before hitting the loop
  pinMode(relayPin, OUTPUT); //
}

void loop() {
  digitalWrite(relayPin, HIGH); // NO connects to COM
  delay(2000);
  digitalWrite(relayPin, LOW); // NC connects to COM
  delay(4000);
}

 

One last thing, I also just noticed it seems to work fine WITHOUT the 3v3 of the Microcontroller to VCC (not sure why, based on the video suggesting it is needed).

 

One last thing, I also just noticed it seems to work fine WITHOUT the 3v3 of the Microcontroller to VCC (not sure why, based on the video suggesting it is needed).

Morning h,
Pleased to hear that you have solved the problem, other users of AAC will benefit from your input.

Note:
the IN path of the terminal block has a series Resistor >> Opto >> LED >> Gnd
So the current [ approx 10mA] for that path is from the MCU PORT pin, ie: when set to an output of 3.3V it will power the IN pin via that path to Gnd [ the VCC is not involved]

BTW: on some versions of that module it does use Vcc, the IN pin is pulled LOW by the MCU PORT pin to operate the relay
Thats VCC >>> Resistor >> Opto >> LED >> IN pin

Good Luck with rest of the project.

E

 

ALRIGHT! That was it, it is working as expected now. I appreciate your patience and help E, thank you!
View attachment 198730
Arduino Sketch Testing Code (if anyone else needs it):

#define relayPin 14 //D5 on ESP8266

void setup() {
  digitalWrite(relayPin, HIGH); //This prevents current from flowing into this pin before hitting the loop
  pinMode(relayPin, OUTPUT); //
}

void loop() {
  digitalWrite(relayPin, HIGH); // NO connects to COM
  delay(2000);
  digitalWrite(relayPin, LOW); // NC connects to COM
  delay(4000);
}

I ran into a similar issue and this conversation helped me a lot with understanding what’s going on. Thanks a lot everyone!!

 

Just to say thanks. This helped me!