ECE497 Project - Andriod App to Speaker

Revision as of 23:00, 12 November 2018 by Lewistd (talk | contribs) (Executive Summary)
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thumb‎ Embedded Linux Class by Mark A. Yoder

Team members: Anne Boxeth, Trey Lewis

Grading Template

I'm using the following template to grade. Each slot is 10 points. 0 = Missing, 5=OK, 10=Wow!

00 Executive Summary
00 Installation Instructions 
00 User Instructions
00 Highlights
00 Theory of Operation
00 Work Breakdown
00 Future Work
00 Conclusions
00 Demo
00 Late
Comments: I'm looking forward to seeing this.

Score:  10/100

(Inline Comment)

Executive Summary

The goal of this project is to interface a simple android application with the BeagleBone. Songs will be able to be chosen/downloaded and controlled from the Android App and played through a speaker connected to the bone either via a USB dongle or through Bluetooth. We are working to support possibly having the option to choose either through the dongle or through a Bluetooth speaker. Another feature that would be neat to include is playing songs through YouTube so you can have a wider range of options to play.

During the project, we have run in various roadblocks. The first roadblock was trying to get a Bluetooth speaker to connect. This is a problem we are still investigating. The Bluetooth dongle will connect once to the speaker but after that, it will 'connect' for a second then disconnect. Another roadblock we encounter was the music playback was choppy and skipped at some points. This was solved by manually setting the sampling rate.


If you have hardware, consider Small Build, Big Execuition for ideas on the final packaging.

Installation Instructions

Give step by step instructions on how to install your project.

User Instructions

Once everything is installed, how do you use the program? Give details here, so if you have a long user manual, link to it here.

Use the program by building the Android application onto an Android device. Everything in this program is controlled from the Android device. The bluetooth on the BeagleBone should be set to discoverable mode. To do this, in the command line input "bluetoothctl", then "discoverable yes", then "quit." The BeagleBone must be discoverable for the phone to find it. The BeagleBone should be running the program found in the Git repo under the AppToSpeaker folder. Start by selecting "discover" and then selecting your BeagleBone device to Bluetooth connect to. Select the song to play once the BeagleBone is connected to the device.


Our project lets you control music on the Bone from your phone. This uses a Bluetooth connect to send commands to the Beagle from your phone. You have all the commands of a basic stereo with the additional ability to choose new music to download.

  • Basic screen when you open the app
  • Trying to discover Bluetooth devices
  • Connected to the BeagleBone via Bluetooth
  • Playing a song
  • Playing custom music file
  • Choose file to download

Include a YouTube demo the audio description.

Theory of Operation

Give a high level overview of the structure of your software. Are you using GStreamer? Show a diagram of the pipeline. Are you running multiple tasks? Show what they do and how they interact.

The basic structure of our program is an Android app sends instructions to an application running on the BeagleBone. The app first 'discovers' the BeagleBone and connects to it via Bluetooth. Then, the user can select to play, pause, resume, or stop playing different songs. The BeagleBone controls the music according to the command using mplayer. The audio output plays through the Bluetooth speaker or a headset, whichever one is currently selected by the mplayer audio driver. Below you can see a diagram on the interaction of different parts of the system.

This is the basic flow of the program.

Work Breakdown

  • Phone connect to bone through app via Bluetooth- Trey
  • Wrote App - Trey
  • Using mplayer to play, pause, resume, and stop music, in python script - Anne
  • Ability to download music from online - Trey
  • Using mplayer to play music from online - team effort (in progress)
  • Connecting beaglebone black to bluetooth speaker - Anne (in progress)
  • Solving choppyness of mplayer when playing music - mostly Trey, little help from Anne
  • Documentation - Anne, little help from Trey (in progress)

Future Work

Here are some ideas that could be neat to implement in the future:

  • Have a way to dynamically load music to the Beagle from the app
  • Play music on multiple audio outputs at the same time
  • Have a display change with the music playing


This project presented some interesting challenges. Using mplayer in the Python application cause the output of the audio to initially skip at some points. We tried many different things to solve this but ultimately the issue was the sampling rate used during playback. Overriding this setting caused the audio to sound a lot better. Another issue we had was getting the Bluetooth set up. Initially, we didn't know that we needed to use a Bluetooth dongle, so it was a lot of work before finally realizing we needed to purchase that. After getting the dongle, the work we did initially worked to connect to the speaker. Then, the BeagleBone stopped connecting to the speaker after turning off the Beagle and turning it back on. We tried a different dongle and installing different packages to monitor Bluetooth, but so far no luck.

Besides these two hiccups, creation of the app to outputting sound went smoothly. The project allowed us to experiment with different peripherals that we thought could make an interesting project. Some things that would be interesting to pursue is sending the music files to the BeagleBone so that you could play any song that you had on your phone. There might also be a way to get the music from other apps to play on the Beagle (basically just use the Beagle as the audio out for the phone). Overall, while there were some difficult parts, we are happy with the outcome of the system as it presented us new ways to connect to and use the BeagleBone.

thumb‎ Embedded Linux Class by Mark A. Yoder