Secret Beeper (Prank)

As an April Fools Day prank for my boss I made this little beeper. It's pretty compact, but allows you to either secret it away on its own or attach to anything magnetic through three 8mm disc magnets on its base.

I used an:

• ESP32 Qt-Py board
• LiPo Battery Backpack
• Piezo-buzzer 
• Small lipo-battery 

It's definitely overkill since all this could be done with analog components, but I wanted to do it quickly and therefore code was easier. The code is so simple I've attached the Arduino sketch below. 

Code:

// Simple Annoying Cricket Chirp Prank
// Iain Z - April Fools Day 2024
#include <ArduinoLowPower.h>
const int buzzer = A0; //Analog output pin
const unsigned int sleepTimes[] PROGMEM = {3, 5, 11, 7, 14, 18}; // Random sleep intervals in mins
void setup(){
  pinMode(buzzer, OUTPUT); // Set buzzer - pin 9 as an output
}
void loop(){
  int freq = random(3700, 3800); // random frequency in this range is picked for this chirp
  float duration = random(40, 70); // random duration chosen for this chirp (miliseconds)
  int chirpCount = random(2,5);
  int numCycles = random(3,5);
  delay(2000);
  for (int j=1; j<=chirpCount; j++){
    for (int i=1; i<=numCycles; i++){
    chirpLoud(freq,duration);
    delay(250);
    }
    delay(750);
  }
  int sleepTime = sleepTimes[random(0, 5)]*60000; //includes translation to miliseconds
  LowPower.deepSleep(sleepTime);
}
void chirpLoud(int freq, float duration) {
  for (int i = 3; i >= 0; i--) {
    tone(buzzer,freq,duration);
    delay(duration);
    noTone(buzzer);
  }
  delay(duration/2);
}