Here’s a breakdown of each line in the code and what it does. This should be helpful for novices trying to understand and write this program.
Line 1: void setup() { This function is called when a sketch starts. Here, we initialize variables, input and output pin modes. It is executed only once when the program starts or the microcontroller is reset.
Line 2: pinMode(8, OUTPUT); This line sets the digital pin 8 as an output pin. This pin will be used for buzzer output. OUTPUT mode allows the pin to emit signals.
Line 3: } This line marks the end of the setup function. All the instructions inside these brackets {} are the body of the setup() function.
Line 4: void loop() { This function does precisely what its name suggests – it loops consecutively, allowing your program to change and respond. It’s used to actively control the Arduino board.
Line 5: buzz(8, 440, 500); This line calls a function named “buzz” that we define later in the program. It sends three values to the function: “8” for the pin number, “440” for the frequency in Hz (this frequency corresponds to the musical note A4), and “500” for the duration in milliseconds.
Line 6: delay(1000); This line causes the program to pause for 1000 milliseconds (or 1 second) before moving to the next line. This creates a pause between each buzz.
Line 7: } End of the loop function.
Line 8: void buzz(int targetPin, long frequency, long length) { This line defines the buzz function, which has three parameters: “targetPin” is the output pin for the buzzer, “frequency” is the frequency of the sound the buzzer will produce, and “length” is how long the sound will last.
Line 9: long delayValue = 1000000/frequency/2; This line calculates the amount of delay between each transition of the sound wave, which determines the frequency of the sound. It’s dividing a second’s worth of microseconds by the frequency to calculate the length of one wave, and then dividing it by two since we need to account for the two phases (high and low) of each cycle.
Line 10: long numCycles = frequency * length/ 1000; This line calculates the number of cycles that the buzzer should produce based on the frequency and the duration of the sound.
Lines 11-17: for (long i=0; i < numCycles; i++){…} These lines create a loop that will run as many times as there are cycles to produce.
Inside this loop:
Line 12: digitalWrite(targetPin,HIGH); This line sends a high signal (electrically ON) to the buzzer, causing it to push out its diaphragm.
Line 13: delayMicroseconds(delayValue); This line causes the program to pause for the calculated delay time. This is half the time of one full wave of the sound.
Line 14: digitalWrite(targetPin,LOW); This line sends a low signal (electrically OFF) to the buzzer, causing it to pull its diaphragm back.
Line 15: delayMicroseconds(delayValue); This line again causes the program to pause for the calculated delay time. This is the second half of one full wave of the sound.
Line 16 and 17: } These lines mark the end of the for loop and the buzz function.
In this way, by alternating pushing and pulling the diaphragm of the buzzer at the specified frequency and for the specified number of cycles, the program creates a sound wave with the desired frequency and duration.
To write and understand this program, a novice programmer should first familiarize themselves with the basic structure of an Arduino program, which consists of the setup() and loop() functions. Then, they can study the syntax of the pinMode(), digitalWrite(), and delayMicroseconds() functions, as well as how to define and call a custom function like the buzz() function in this program.
It’s also important to understand the basics of sound physics, specifically how sound frequency determines the pitch of the sound, and how sound is produced by vibrations, which in this case are caused by pushing and pulling the diaphragm of the buzzer.
Moreover, understanding the logic behind converting frequency into delay value between the transitions and the calculation of the number of cycles will give the novice an idea of how the code is producing the required sound wave.
By mastering these concepts and practices, a novice can not only understand this program but also modify it to produce different sounds or even melodies with the buzzer.
