Pot driven relay toggle

example.ino

// This is a global variable
const int relay1 = 7; // let's call pin 7 relay1

// This is the setup function which gets run once, when the MCU gets reset
void setup() {
  pinMode(relay1, OUTPUT); // set pin 7 to an output pin
  digitalWrite(relay1, HIGH); // set pin 7 high
}

// This is the loop function which gets called repeatedly forever
void loop() {
  int value = 100 + analogRead(A0); // read analog pin 0 and store it in `value` (adding 100 means it won't go below that)
  
  digitalWrite(relay1, LOW); // set pin 7 low
  delay(value); // wait `value` ms
  digitalWrite(relay1, HIGH); // set pin 7 high
  delay(value); // wait `value` ms
}