With excellent assistance from the Arduino forum, I now have a working version of the circuit to play a random MP3 file each time the distance sensor is triggered. It doesn’t play a few of the files when they are triggered, but this has been tested elsewhere and the code works, so I need to investigate the files themselves, it seems.
And here’s the code used.
#include <SoftwareSerial.h>
#define ARDUINO_RX 5 //should connect to TX of the Serial MP3 Player module
#define ARDUINO_TX 6 //connect to RX of the module
#define trigPin 13 //for the distance module
#define echoPin 12
SoftwareSerial mySerial(ARDUINO_RX, ARDUINO_TX);//init the serial protocol, tell to myserial wich pins are TX and RX
////////////////////////////////////////////////////////////////////////////////////
//all the commands needed in the datasheet(http://geekmatic.in.ua/pdf/Catalex_MP3_board.pdf)
uint8_t Send_buf[8] = {0} ;//The MP3 player undestands orders in a 8 int string
//0X7E FF 06 command 00 00 00 EF;(if command =01 next song order)
#define NEXT_SONG 0X01
#define PREV_SONG 0X02
#define CMD_PLAY_W_INDEX 0X03 //DATA IS REQUIRED (number of song)
#define VOLUME_UP_ONE 0X04
#define VOLUME_DOWN_ONE 0X05
#define CMD_SET_VOLUME 0X06//DATA IS REQUIRED (number of volume from 0 up to 30(0x1E))
#define SET_DAC 0X17
#define CMD_PLAY_WITHVOLUME 0X22 //data is needed 0x7E 06 22 00 xx yy EF;(xx volume)(yy number of song)
#define CMD_SEL_DEV 0X09 //SELECT STORAGE DEVICE, DATA IS REQUIRED
#define DEV_TF 0X02 //HELLO,IM THE DATA REQUIRED
#define SLEEP_MODE_START 0X0A
#define SLEEP_MODE_WAKEUP 0X0B
#define CMD_RESET 0X0C//CHIP RESET
#define CMD_PLAY 0X0D //RESUME PLAYBACK
#define CMD_PAUSE 0X0E //PLAYBACK IS PAUSED
#define CMD_PLAY_WITHFOLDER 0X0F//DATA IS NEEDED, 0x7E 06 0F 00 01 02 EF;(play the song with the directory \01\002xxxxxx.mp3
#define STOP_PLAY 0X16
#define PLAY_FOLDER 0X17// data is needed 0x7E 06 17 00 01 XX EF;(play the 01 folder)(value xx we dont care)
#define SET_CYCLEPLAY 0X19//data is needed 00 start; 01 close
#define SET_DAC 0X17//data is needed 00 start DAC OUTPUT;01 DAC no output
////////////////////////////////////////////////////////////////////////////////////
void setup() {
Serial.begin(9600); //Start our Serial coms for serial monitor in our pc
mySerial.begin(9600); //Start our Serial coms for THE MP3
delay(500); //Wait chip initialization is complete
sendCommand(CMD_SEL_DEV, DEV_TF); //select the TF card
delay(200); //wait for 200ms
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
randomSeed(analogRead(A0));
}
void loop() {
if (measureDistance(trigPin, echoPin) < 10) {
int randTrackNo;
randTrackNo = random(1, 9);
sendCommand(0x03, randTrackNo);
Serial.print("Playing track:");
Serial.println(randTrackNo);
delay(1000); //wait to avoid errors
}
delay(300);
}
void sendCommand(int8_t command, int16_t dat) {
delay(20);
Send_buf[0] = 0x7e; //starting byte
Send_buf[1] = 0xff; //version
Send_buf[2] = 0x06; //the number of bytes of the command without starting byte and ending byte
Send_buf[3] = command; //
Send_buf[4] = 0x00; //0x00 = no feedback, 0x01 = feedback
Send_buf[5] = (int8_t)(dat >> 8); //datah
Send_buf[6] = (int8_t)(dat); //datal
Send_buf[7] = 0xef; //ending byte
for (uint8_t i = 0; i < 8; i++) {
mySerial.write(Send_buf[i]) ; //send bit to serial mp3
Serial.print(Send_buf[i], HEX); //send bit to serial monitor in pc
Serial.print(" ");
}
Serial.println();
}
long measureDistance(int trigger, int echo) {
long duration, distance;
digitalWrite(trigger, LOW); //PULSE ___|---|___
delayMicroseconds(2);
digitalWrite(trigger, HIGH);
delayMicroseconds(10);
digitalWrite(trigger, LOW);
duration = pulseIn(echo, HIGH);
distance = (duration / 2) / 29.1;
Serial.print("distance: ");
Serial.println(distance);
return distance;
}