https://medium.com/jungletronics/ifr-520-mos-module-dorobot-4a3dd45ba2b7

_60_IFR520_02.ino

#define control1 8                  // pin that controls the MOSFET
#define control2 9                  // pin that controls the MOSFET

void setup() {
                                    
  pinMode(control1, OUTPUT);        // define control pin as output
  pinMode(control2, OUTPUT);        // define control pin as output
  Serial.begin(9600);

}

void loop() {
                                    

  digitalWrite(control1, HIGH);     // turn the MOSFET Switch ON
  digitalWrite(control2, HIGH);     // turn the MOSFET Switch ON
  delay(2000);                      // Wait for 2000 ms or 2 second

  digitalWrite(control1, LOW);      // Turn the MOSFET Switch OFF
  digitalWrite(control2, LOW);      // Turn the MOSFET Switch OFF
  delay(2000);                      // Wait for 2000 ms or 2 second


}