Description

The simpliest project with a photoresistor and a DFPlayer Mini. When the photoresistor receives light, starts the first mp3 of the SD card. Therefore, in the dark the mp3 stops.

Library dependencies

This sketch has the following dependencies:

• SoftwareSerial.h: for the serial communication with the DFPlayer. Already installed with the Arduino IDE.
• DFRobotDFPlayerMini.h: to interact with the DFPlayer. You will need to download and install it in your Arduino libraries folder.

Requisites and parts

• 1 x Arduino Uno
• 1 x Photoresistor
• 1 x 10K Ohm resistor
• 1 x 1K Ohm resistor
• 1 x DFPlayer Mini
• 1 x SD card formatted as fat16 or fat32
• 1 x mp3 file on the SD card

Diagram

The code

// Initializing
boolean isPlaying = false;
boolean isStopped = true;

SoftwareSerial mp3Serial(RXPin, TXPin);
DFRobotDFPlayerMini mp3Player;

// Logic
void loop()
{
  int PRValue = digitalRead(PRPin);

  if ((PRValue == HIGH) && !(isPlaying) ){
    Serial.println(F("Photoresistor high, play."));
    isPlaying = !isPlaying;
    isStopped = !isStopped;
    mp3Player.play(1);
  } else if ((PRValue == LOW) && !(isStopped)) {
    Serial.println(F("Photoresistor low, stop."));
    isPlaying = !isPlaying;
    isStopped = !isStopped;
    mp3Player.stop();
  }
  delay(500);
}