Introduction 

      Many people like to listen to music while doing different activities. If we want to control a device playing music we need to be next to it, which may be a problem in some situations. For example, if you are hanging out with some friends in your house and you want to control the music that is being played you would need to stay by the player or keep coming to it to control the music. This is only one case in which you are limited by physical contact to control the player. In order to eliminate this issue i thought of developing a MP3 player controlled by Bluetooth. A cellphone with an Android app that send information through Bluetooth is used to control the MP3 player.

Development Process:

    My first plan was to make an MP3 Player with a simple button interface, 2 intern speakers and a Bluetooth module. For controlling the MP3 Player I wanted to develop an Android app which would be my MP3 interface. Due to the limited amount of time for developing this project I needed to change plans and make a basic MP3 Player with 5 buttons interface, using self powered speakers instead of my inter speakers. I also gave up about developing an Android app and I used one downloaded  from Google Play. 

Materials:

• Bluetooth  module RS232 TTL HC-05
• MP3 decoder ( Breakout Board for VS1053 MP3 and MIDI )
• SD card and SD card adapter  
• Protoboard, wires, sockets, resistors
• 5 buttons
• 3.5mm Audio jack
• Cellphone and Android app to send data via Bluetooth 
• MP3 case 

Verplank Diagram

Verplank_Diagram_LuizLouro.pdf

State Diagram

Android App

     Since I did not have time to build my own Android app I searched for a app that has an interface to communicate with arduino via Bluetooth. The app I found was part of a project on the website instructables. The image below shows the app interface. Fist when you open the app it will ask to connect to the Bluetooth module and then it will go to a second interface that gives the possibility of sending data and showing data received from Bluetooth module. As shown in the image I used this interface to show the MP3 state and the song title.

App Interface:

First :     https://docs.google.com/file/d/0B5J238VnF4PhaFdMXzN3dVRfTFk/edit?usp=sharing

Second : https://docs.google.com/file/d/0B5J238VnF4PheHBUSVBLVmpHQzA/edit?usp=sharing

Ardunino Bluetooth android app link: https://play.google.com/store/apps/details?id=arduino.bluetooth.terminal

Instructables project link: http://www.instructables.com/id/Arduino-AND-Bluetooth-HC-05-Connecting-easily/step4/Connect-arduino-To-android-Device/

Circuit 

    I  Built the circuilt on the breadboard and made sure the MP3 player works. Then added the Bluetooth module and tesedt the communication between the device and the Bluetooth module. 

     After I duplicated the circuit on the ProtoBoard, soldering sockets to hook the components and wires. Tested again and made sure everything is working in the same way before.

Final circuit:

MP3 Player Case

     I chose to make a simple MP3 case. The images below show some ideas.

https://docs.google.com/file/d/0B5J238VnF4PhWDNFS0NDcmRfYlE/edit?usp=sharin

https://docs.google.com/file/d/0B5J238VnF4PhbGszMFZNdHdIUmc/edit?usp=sharing

     I drew my final design on illustrator and used the laser cutter to make the box. My first intention was to make a wood case as a prototype and then make a definitive of acrylic , but I did not have time, so I used the wood box as my final version.

Code: FinalCode_LuizLouro.txt  

Challenges

• Passing the circuit from breadboard to protoboard
• Make the Bluetooth module work with the MP3 player.

Video:  http://youtu.be/BNRGxtKZtfU

For future versions I plan to add:

- Android app with MP3 player interface

- Intern speakers to MP3 Player 

- New software functionalists such as seeking, streaming music from cellphone to MP3 player

- Make a smaller and better looking case