// Button Entropy Injection for random() and randomSeed()
//https://wokwi.com/projects/421713344617482241
// for https://forum.arduino.cc/t/int-rndseed-analogread-a0-analogread-a0/1349109

const int ButtonPin = 2;

void pauseForButtonEntropy(const int ButtonPin) {
  Serial.println("Press button to start");
  while (digitalRead(ButtonPin) == HIGH) { // wait for button press
    ; //do nothing
  }
  while (digitalRead(ButtonPin) == LOW) { // protect  against button initially being pressed
    ; //do nothing
  }
  // comment this line to inhibit re-seeding:
  randomSeed(micros() + random()); // inject entropy, rather than overwrite entropy -- good for repeated use
}

void setup() {
  Serial.begin(115200);
  pinMode(ButtonPin, INPUT_PULLUP);
}

void loop() {
  pauseForButtonEntropy(ButtonPin);
  Serial.println(random());
  //delay(500); // simple rate-limiting -- need some sort of debouncing for noisy buttons
}