Button-Controlled Nokia Ringtone using a Passive Buzzer

Figure 1. Button-controlled passive buzzer circuit created in Tinkercad. The circuit along with the code can be tried and tested through this simulation.

Introduction

I have started to play around with a new electronic component: the passive buzzer. I chose this instead of its active counterpart because it offers more flexibility, such as choosing the tone (cite or reference because not sure).

Methodology

Figure 2. Electrical connections for the button-controlled passive buzzer circuit created using Tinkercad. I used a pullup configuration for the button switch using a 220-Ω resistor.

• Passive Buzzer
• Push Button
• (1) 220-Ω resistor
• Arduino UNO microcontroller
• Connector wires
• (Optional) Breadboard power supply module

Code Breakdown

⚠IMPORTANT: This section is a detailed description of the code and can be skipped to the overall code here.

To make a sound, a square wave must be passed into the passive buzzer. The frequency and duration of the passive buzzer can easily be defined using tone() function, which accepts three arguments in the following order: pin number, frequency (in Hz) and duration (in ms). Below we will go step-by-step with the code. We subdivide the code into three parts: parameter initialization, void setup(), and void loop().

Parameter Initialization

We should define first the pin that will feed signal into the passive buzzer:

int buzzpin = 7;

Above is the most basic defined parameter. If we would like to add other settings such as ringing the buzzer after pressing a button, then define the pin that detects a pressed button:

int on_switch = 4;

The following is just optional but adds an exciting feature. I decided that I would like the buzzer to play the Nokia ringtone whenever the button was pressed. I just googled the key frequencies used and their duration. I was not sure of the exact duration of each note so I just listed a whole number equivalent to the type of musical note used. Then I defined a multiplier (mult), which I adjusted while modifying the code to see what value yields the realistic ringtone sound.

int mult = 200; // Multiplier
int freq[13] = {1319, 1175, 740, 831, 1109, 988, 587, 659, 988, 880, 554, 659, 880}; // Key/Note frequencies
int time[13] = {1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 4}; // Key/Note relative duration

void setup()

void setup() is also an initialization part, but the the previous one is more about defining the variables. In this part, we define whether the pins are input or output.

buzzpin is an OUTPUT while on_switch is INPUT because it reads when the switch is pressed:

void setup() {
  // put your setup code here, to run once:
  pinMode(buzzpin, OUTPUT);
  pinMode(on_switch, INPUT);
}

void loop()

This is the main part of the code where the electronic circuit operation is executed. The operational lines of code are written inside the void loop()'s environment:

void loop() {
  // put your main code here, to run repeatedly:
}

For a simple buzzer ringing, we can write the following using tone() function:

tone(buzzpin, frequency, duration);

With the button, we first read its state:

int val = digitalRead(on_switch);

If it is pressed, I put two possible options. First option is just the template below:

tone(buzzpin, 250, 1000);

The second one is where the Nokia ringtone is played:

for (int i = 0; i < 13; i++) {
  tone(buzzpin, freq[i], time[i]*mult);
  delay(time[i]*mult);
}

I am not particularly sure why do I have to add a delay() after each note since in principle, its duration must be taken into account by tone() function. However, without, the ringtone sounds a little weird, so I had to add that delay. I am just leaving this as an open question which I will try to understand later on.

Since these possibilities only play if the button is pressed, do not forget to put these codes inside a conditional environment because otherwise, it will continue to play:

if (val == 1) {
  // // Option 1
  // tone(buzzpin, 250, 1000);

  // Option 2
  for (int i = 0; i < 13; i++) {
    tone(buzzpin, freq[i], time[i]*mult);
    delay(time[i]*mult);
  }
}

Overall Code

int buzzpin = 7;
int on_switch = 4;
int mult = 200;
int freq[13] = {1319, 1175, 740, 831, 1109, 988, 587, 659, 988, 880, 554, 659, 880};
int time[13] = {1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 4};
void setup() {
  // put your setup code here, to run once:
  pinMode(buzzpin, OUTPUT);
  pinMode(on_switch, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  // tone(buzzpin, 250);
  
  // For fun
  int val = digitalRead(on_switch);
  if (val == 1) {
    // // Option 1
    // tone(buzzpin, 250, 1000);

    // Option 2
    for (int i = 0; i < 13; i++) {
      tone(buzzpin, freq[i], time[i]*mult);
      delay(time[i]*mult);
    }
  }
}

Problems

One of the problems I think I have with this electronic circuit is that there is interrupt option. Even though I push the button again, the sound is not interrupted or will not restart. I think I should consider an interrupt next time.