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Welcome

In this project, we will use a PIR sensor to detect human presence and a speaker to simulate a doorbell, similar to the entrance doorbells in convenience stores. When a pedestrian appears within the range of the PIR sensor, the speaker will ring, mimicking a doorbell.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Elite Explorer Kit	300+	Elite Explorer Kit

You can also buy them separately from the links below.

COMPONENT INTRODUCTION	PURCHASE LINK
Arduino Uno R4 WiFi	-
Breadboard	BUY
Jumper Wires	BUY
Resistor	BUY
PIR Motion Sensor Module	BUY
Audio Module and Speaker	-

Wiring

Schematic

Code

Note

• You can open the file 01_welcome.ino under the path of elite-explorer-kit-main\fun_project\01_welcome directly.

• Or copy this code into Arduino IDE.

How it works?

Here is a step-by-step explanation of the code:

1. Include Header Files:

   Include two header files, analogWave.h and pitches.h. The analogWave.h file contains the definition of the analogWave class, while pitches.h contains the definitions of musical notes.

2. Instantiate Objects and Define Constants:

   Create a wave object using the analogWave class and define PIR_PIN as 2, which is the pin connected to the PIR sensor.

3. Melody Array:

   The melody array defines a musical melody, with each note followed by a number representing its duration. Negative numbers represent dotted notes (increasing the duration by 50%).

4. Global Variables:

   Define some global variables for sharing data between functions.

5. setup():

   Initialize PIR_PIN as an input and set the frequency of the sine wave to 10 Hz using wave.sine(10).

6. loop():

   Continuously monitor the value of the PIR sensor. If human presence is detected (pirValue is HIGH), call the playMelody() function to play the melody and wait for 10 seconds to prevent repetitive playback of the melody.

7. playMelody():

   This function calculates the duration of each note based on the data in the melody array and plays the corresponding note. There is a brief pause between notes. The function sets the frequency of the waveform using wave.freq() and controls the duration of the notes and pauses between notes using the delay() function.

   Note: Ensure that the pitches.h header file indeed exists before running this code.