18. Active Buzzer

This lesson uses: Arduino UNO R3 board, TinkerBlock TK36 Active Buzzer module, jumper wires (or breadboard). Learn to control the active buzzer with digitalWrite() and const; outcome: buzzer on 0.5 s, off 0.5 s, repeat.

1. Wiring

Connect TK36 Active Buzzer to Arduino:

• GND → Arduino GND
• VCC → Arduino 5V
• SIGNAL → Arduino D3
• NC leave unconnected

2. New sketch

1. Arduino IDE: File → New (or Ctrl/Cmd + N) to create a blank sketch
2. Confirm board and port are selected (same as Lesson 01)
3. Type the code below into the default setup() and loop() yourself

3. Program structure

Same as last lesson: two fixed blocks setup() and loop().

• setup(): Tell the board “pin 3 for buzzer”; start serial (optional); runs once.
• loop(): Keep repeating “buzzer on → wait → buzzer off → wait → repeat”.

The result is on–off cycles; active buzzer has fixed pitch, no tuning.

4. Code to write

Type the code below line by line into setup() and loop() (do not copy-paste; typing it yourself helps you remember):

#define BUZZER_PIN 3   // Buzzer on D3
const int DURATION = 500;   // Duration in milliseconds

void setup() {
  pinMode(BUZZER_PIN, OUTPUT);   // D3 output for buzzer
  Serial.begin(9600);
  Serial.println("Active buzzer program started");
}

void loop() {
  // Buzzer on
  digitalWrite(BUZZER_PIN, HIGH);
  Serial.println("Buzzer on");
  delay(DURATION);
  
  // Buzzer off
  digitalWrite(BUZZER_PIN, LOW);
  Serial.println("Buzzer off");
  delay(DURATION);
}

Program notes

Overall idea: Active buzzer has internal oscillator; HIGH = on, LOW = off; use digitalWrite. const int DURATION holds on/off time (ms) so you can change it in one place. const is like #define but typed; good for constants.

const vs #define:

• #define DURATION 500: Preprocessor replacement before compile
• const int DURATION = 500: Real variable with type checking, safer. Prefer const for constants

5. Hands-on

1. After entering the code, click Verify (✓) to compile
2. Click Upload (→) to upload to the board
3. Listen to TK36: on 0.5 s, off 0.5 s, repeat
4. Try yourself:
   • Change DURATION to change on/off time
   • Try fast on/off (e.g. delay(100)) for a “beep-beep”

Expected result: As in the figure.

Proceed to Lesson 19.

6. Common issues

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