Arduino adventures: triggering MP3 files with distance sensor

Finally got the circuit built to be able to read the distance sensor and the MP3 board, so now I can trigger a selected MP3 to play when something passes the sensor. What I built previously was overly-complicated and was most likely shorting out.

The videos show the sensor working from 1ocm distance, but this is easy to vary. They also show the sound looping if the object sensed stays in range, and also two separate pieces of audio being triggered. This was changed in the code before being uploaded. The code used is below.

Next to make it play a random one of the MP3 files each time the sensor is triggered!

//code rearranged by Javier Muñoz 10/11/2016 ask me at
#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(
static int8_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 DEV_TF 0X02 //HELLO,IM THE DATA REQUIRED


#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);


void loop()
sendCommand(CMD_PLAY_WITHFOLDER, 0X0203);//play the third song of the second folder
delay(1000);//wait to avoid errors

void sendCommand(int8_t command, int16_t dat)
 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

long measureDistance(int trigger,int echo){
   long duration, distance;
  digitalWrite(trigger, LOW);  //PULSE ___|---|___
  digitalWrite(trigger, HIGH);
  digitalWrite(trigger, LOW);
  duration = pulseIn(echo, HIGH);
  distance = (duration/2) / 29.1;
  return distance;


Aperture – initial sketches for musical visualisation projection

Some initial sketches for projecting light through apertures. The apertures will be based on a visualisation of a song or piece of audio. These are the shapes that will make up the apertures.

Aperture - initial sketches for musical visualisation projection
Aperture – initial sketches for musical visualisation projection
Aperture - initial sketches for musical visualisation projection - version 2
Aperture – initial sketches for musical visualisation projection – version 2

Inspiration for the ‘Space Rock’ audio player

I want to make one of these. Imagining them as a limited edition for a band or artist, loaded with samples of their work, so the user can create their own soundscapes. Could be a version using the Voyager Sounds collection?

And also a nod to the interactive tilt radio by Luka Or, whose shape initially inspired the ‘Space Rock’.