View source for S16: Sound Buddy

=== Grading Criteria ===
<font color="green">
*  How well is Software & Hardware Design described?
*  How well can this report be used to reproduce this project?
*  Code Quality
*  Overall Report Quality:
**  Software Block Diagrams
**  Hardware Block Diagrams
**:  Schematic Quality
**  Quality of technical challenges and solutions adopted.
</font>

== Project Title ==
[[File:SP16_Sound_Buddy_Logo_1.jpg|350px]]

== Abstract ==
You turn up your music to rock out to but you forget your dancing shades in the other room so you run to the other room to look for it and by the time you find it your favorite part has already passed. Now, you have to start the song all over again.

What a bummer!

Sound Buddy is an affordable wireless speaker system designed to play your favorite music in any room you are walking into or every room. Load your favorite MP3 songs onto a micro SD card and plug it into Sound Buddy. Place the Sound Buddy speakers in any room, and you are ready. You can jam out to your favorite song and if you forget your favorite dancing shades again, Sound Buddy will switch the speaker in another room to blast your song. You will never miss your favorite part again!

Developed with amazing technologies such as the Nordic transceiver device, MP3 decoder, SJOne board, and the powerful FreeRTOS, Sound Buddy comes to life!

== Objectives ==
The implementation of Sound Buddy can be broken down into four main efforts.

'''Reading the MP3 File'''
The MP3 file is read from a loaded mircoSD card to the SJSU-ONE board's flash memory. 

'''Converting and Sending MP3 over Nordic Wireless'''
The MP3 is wirelessly sent from the Sender-board's flash memory to the Receiver-boards' flash memory. 

'''Receiving MP3 Files'''
The Receiver-boards receive the MP3 file and prepare the MP3 file for transmission over an I2C communication bus to the MP3 decoder board.

'''Decoding MP3 to Audio'''
The decoder board receives the file over the SPI communication bus and reformats the file to send raw data to the DAC where the speakers will be connected.

=== Team Members - Responsibilities ===
*  Brigitte De Leon - Tell everyone what to do
*  Catherine Gamboa - Be early to all the meetings
*  Hudo Assenco     - Wake up
*  Yang Thao        - Buy everything

The team members worked closely together every weekend of their hectic lives in the spring semester of 2016 to produce a beating heart for this project. Brigitte and Hudo worked on the Nordic wireless device code to get the data sent from one board to another in a streaming fashion. Catherine and Yang worked on the MP3 decoder circuit to be able to properly decode the MP3 file from the SJ-One board. Hudo and Catherine designed the PCB board that houses the MP3 decoder circuit. Yang made sure to supply the team with all of the material and then some. Brigitte brought the team together and kept the vision alive. Everyone put in time and effort to keep the Wiki document up-to-date through the duration of the project. Each sub team ran their own tests to assure that the subsystems were working as designed. The integration tests and debugging were tackled by all the members.

== Schedule ==
{| class="wikitable" style="width: 90%; height: 40%;"
|-
! scope="col" style="width: 75px"| Week#
! scope="col" style="width: 75px"| Date
! scope="col"| Task
! scope="col"| Actual
|-
! scope="row"| 1
! style="text-align: center;"| 03.14
| <li>Finalize Schedule <li>Determine PCB board circuit<li>Order Parts<li>Update Wiki
| <li>Completed
|-
! scope="row"| 2
! style="text-align: center;"| 03.21
| <li>Design PCB schematic on Eagle<li>Review Nordic Wireless component on SJOne Board<li>Update Wiki
| <li>Completed
|-
! scope="row"| 3
! style="text-align: center;"| 03.28
| <li>Order PCB<li>Develop Nordic communication protocol<li>Write code to allow Nordic wireless communication between two boards<li>Update Wiki
| <li>PCBs received <li>Completed
|-
! scope="row"| 4
! style="text-align: center;"| 04.04
| <li>Build MP3 decoder prototype circuit and verify its functionality<li>Verify the Nordic wireless data transfer code works<li>Update Wiki
| <li>Completed
|-
! scope="row"| 5
! style="text-align: center;"| 04.11
| <li>Load small MP3 into SD card and send out to MP3 decoder to hear audio<li>Update Wiki
| <li>Completed.<li>Debugging MP3 Decoder prototype<li>Test Nordic wireless mesh commands<li>Solder ICs onto the PCBs
|-
! scope="row"| 6
! style="text-align: center;"| 04.18
| <li>Integrate the system (SD from Master -> Nordic Wireless -> Flash -> MP3 decoder circuit -> Speakers)<li>Update Wiki
| <li>Delayed progress...<li>Debugging MP3 Decoder prototype<li>Updating Nordic wireless class to remove delays<li>Send a file from one board to another with Nordic<li>Continue to solder ICs onto the PCBs
|-
! scope="row"| 7
! style="text-align: center;"| 04.25
| <li>Solder parts onto PCB<li>Integrate into test system<li>Update Wiki
| <li>Completed<li>Debugging MP3 Decoder prototype<li>Updating Nordic wireless class to send single byte
|-
! scope="row"| 8
! style="text-align: center;"| 05.02
| <li>Integration test<li>Update Wiki
| <li>Delayed progress...<li>Developed Nordic code to send a file to another board<li>Debugging MP3 Decoder prototype
|-
! scope="row"| 9
! style="text-align: center;"| 05.09
| <li>System test<li>Update Wiki
| <li>Delayed progress...<li>Optimizing Nordic code to send a file to another board<li>Debugging MP3 Decoder prototype
|-
! scope="row"| 10
! style="text-align: center;"| 05.16
| <li>Run final tests<li>Prepare for DEMO --> 05.24
| <li>Integration<li>PANIC!...JK<li>Completion of project's phase one
|}

== Parts List & Cost ==
The parts tabulated below is used to keep track of what was purchased but does not represent what is needed in the project. Refer to the circuit drawings below to determine what is needed. During testing, extra devices were used to test and debug and replace burnt devices. Those dead components lay peacesully in our project graveyard.
{| class="wikitable"
|-
! scope="col"| Item#
! scope="col"| Part Desciption
! scope="col"| Qty
! scope="col"| Cost per Item
! scope="col"| Cost
|-
! scope="row"| 1
| STA013 MP3 Decoder Chip
| 2
| $11.67
| $23.34
|-
! scope="row"| 2
| CS4334 DAC
| 2
| $2.97
| $5.94
|-
! scope="row"| 3
| Audio Jack 3.5mm
| 3
| $1.50
| $4.50
|-
! scope="row"| 4
| Crystal 14.7456MHz
| 2
| $0.95
| $1.90
|-
! scope="row"| 5
| Printed Circuit Boards
| 2
| $-.--
| $32.05
|-
! scope="row"| 6
| SparkFun SOIC to Dip Adapter 8-pin
| 1
| $2.95
| $2.95
|-
! scope="row"| 7
| SparkFun SOIC to Dip Adapter 28-pin
| 1
| $7.90
| $7.90
|-
! scope="row"| 8
| Breakaway headers
| 2
| $1.50
| $3.00
|-
! scope="row"| 9
| Screw Terminals 3.5mm Pitch(2-Pin)
| 3
| $0.95
| $2.85
|-
! scope="row"| 10
| Antennas
| 3
| $4.20
| $12.60
|-
! scope="row"| 11
| Resistors
| 10
| $0.19
| $1.92
|-
! scope="row"| 12
| Capacitors
| 120
| $---
| $20.11
|-
! scope="row"| 13
|Inductors
| 2
| $0.19
| $0.38
|-
! scope="row"| 14
| Voltage Regulators
| 2
| $0.62
| $1.24
|-
! scope="row"| 15
| SJOne Board
| 3
| $80.00
| $240.00
|-
! scope="row"| 
| Total Cost
|  
| $-.--
| $-.--
|-
|}

== Design & Implementation ==
The following sections will walk you through the system design and dive into the implementation of Sound Buddy. 

After reading through the sections, you'll be able to understand what makes up Sound Buddy's beating heart.

=== Hardware Design ===

The hardware design was limited by the pins that the SJOne board provided. Luckily, this was not an issue for Sound Buddy. The protocols used were SPI/SSP and I2C so the number of pins were already availble for use of communication. A PCB was designed to house the MP3 decoder circuit. This PCB is mounted right on top of the SJOne board enclosing the unit as one functional device.

==== System Design ====
{|
|-
| [[File:S16 Sound Buddy System Design.jpg|400px|left|thumb]]
| Sound Buddy's core component is the SJOne board. For more information about the SJOne board click this link <span class="plainlinks">[http://www.socialledge.com/sjsu/index.php?title=SJ_One_Board SJOne board]</span> or visit the main page of this Wiki. 

Its system is composed of a sender device and one or more receiver devices. An MP3 file will be stored on the micro SD card which will be inserted into the sender's SD slot. The sender device will read and send out the raw MP3 data over the Nordic wireless protocol. Each device uses the built-in Nordic wireless transceiver which allows for one-way communication from the sender to the receiver(s). 

Plugged onto each on the other receivers is the MP3 decoder circuit. The receiver device will be waiting for the MP3 data. Once it detects data has been sent over, it begins to process the data by sending it out to the MP3 decoder. The MP3 decoder translates the raw data and sends it out to the on-board DAC. The DAC converts the raw data into audible signals that get pushed out to the audio0 jack where the speakers play the music. 

Now, that was a mouthful. Let's dive deeper into each of the component design. 
|}

<br><br>
==== Sender Board ====
{|
|-
| The sender board uses the SD card and the [https://www.sparkfun.com/datasheets/Components/SMD/nRF24L01Pluss_Preliminary_Product_Specification_v1_0.pdf Nordic wireless transceiver] onboard. Using the SPI protocol, the SD card will be enabled for I/O purposes. There is a total of four wires utilized namely the SCK, MOSI, MISO, and CS. These wires are connected internally and the data transfer and chip select are handled by the driver and application code. 

Similar to the SD card, the Nordic transceiver uses SPI protocol to send and receive data. This, too, is hooked up internally and the initialization and function are done through coding. The additional hardware part attached to the SJOne board is the 2.4GHz Duck Antenna RP-SMA to support the Nordic wireless data transfer. The Nordic data transfer can be sent on an on-air data rate of 250 kbps, 1Mbs, or 2Mbps depending on configuration. It has a maximum speed of 10Mbps on the SPI line and 3 separate 32 bytes TX and RX FIFO. On page 21 of the Nordic nrf24l01+ datasheet, the state diagram fro communication can be found. Standby-II mode was used because it was determined to produce the fastest data transfer speed. If the TX FIFO detects a data packet uploaded, then the PLL starts and transmits immediately after PLL delay. To drive the Nordic device, the nrf24L01Plus class (included in the SJOne FreeRTOS project) was used to build a driver class. The driver simply checked if whether the TX FIFO is full and if it's not, data will be sent. It uses a polling method to achieve this.

And, that is it for the sender device! Let's move on to the receiver device.
| [[File:S16 Sound Buddy Master Board.png|350px|right|thumb]]
|}

==== Receiver Board ====
{|
|-
| [[File:S16 Sound Buddy Receiver Board.png|600px|left|thumb]]
| The design of the receiver board is very similar to the sender board. Since its microcontroller is also the SJOne board, the onboard Nordic wireless transceiver and SD card slot were used for data transfer and storage. The pins on the board for the SPI protocol are the same as those indicated in the sender board. A chip select pin was needed to enable the MP3 decoder. A GPIO pin from the SJOne board was configured for that purpose. The MP3 decoder board is connected on top of the SJOne board. The MP3 decoder shares the same SSP1 lines as the SD card. The software controls where the data transfer occurs. The MP3 decoder, also, utilizes the I2C protocol for initialization. The MP3 decoder circuit will be dissected later. Lastly, a speaker with an AUX port is attached to the MP3 decoder.
|}

==== MP3 Decoder ====
This circuit is based on the [https://www.pjrc.com/mp3/sta013.html#config tutorial] that details how to use the STA013 chip. The MP3 decoder circuit uses an STA013 MP3 decoder chip to translate raw MP3 data to audible data. A detailed data sheet can be found at [https://www.pjrc.com/mp3/sta013.html STA013 MP3 Decoder].
We used the standard configuration suggested by the manufacturer which recommends that all of the voltage sources higher than 3.3V be brought down to 3.3V to safely operate the device. Since the voltage supply from the SJOne board is 3.3V, this was not an issue. 

For the data coming out of the MP3 decoder to produce music through speakers, the [https://www.cirrus.com/en/pubs/proDatasheet/CS4334-5-8-9_F6.pdf CS4334 DAC] is used. This chip operates on a 5V supply so the SJOne board could not be used as a source. Instead, a 9V battery is used to supply the power. A 5V regulator circuit using a [https://www.sparkfun.com/datasheets/Components/LM7805.pdf 7805 voltage regulator] was built to step down the voltage level supply to prevent damage to the DAC device. 

An audio jack is tied to the output of the DAC device to send music out to speakers with an auxiliary port. The speakers are powered internally with a rechargeable baterry. Any off-the-shelf speaker can be transformed into a Sound Buddy receiver. 


[[File:S16 Sound Buddy MP3 Decoder Board.png|800px|left|thumb]]
Some assumptions are made about the usage of the STA013 device according to the tutorial. To summarize, for "normal" usage, its assumed that the STA013 will run off multimedia mode. The device will detect the MP3 data's bitrate and will send a signal that requesting for data. Data is fed to the STA013 up to 20Mbit/sec. The correct clock and data out to the DAC is also handled by the device. The STA013 will be driving the DAC and the output clock to synchronize with it. Since the tutorial uses a Cs4334 DAC chip in conjunction with a 14.7456 MHz crystal, those devices were used in the MP3 decoder as well. The DAC was chose due to it being inexpensive and its ability to output audio without noise.
<br>
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The following is an illustration of the circuit described in the STA013 tutorial. Each significant portion of the circuit is boxed and labeled.
[[File:S16 Sound Buddy MP3 Decoder Schematic.png]]
<br>
<br>
<br>
To package the MP3 decoder circuit nicely, a PCB was designed and printed to house the circuit. [https://learn.sparkfun.com/tutorials/how-to-install-and-setup-eagle EAGLE PCB] software was used to design the board layout. [https://oshpark.com/ OSH Park] was used to print the boards since the supply location was location locally in the Silicon Valley and the cost was affordable.

LEDs were added in pins for enable and data signals to assist with debugging to assure that the MP3 was functioning as designed.
<br>
{|
|-
| [[File:S16 SoundBuddy PCB layers.png|500px|left]]
| The illustration on the left is the layout the devices and interconnections on the board. It showcases both the top and bottom layers. The components were positioned with the thought of ease during the soldering of the devices and accessiblitity of the pins and ports.
<br>
<br>
To the right are the images of the top and bottom of the expected layouts of the board. The PCB was designed to fit snuggly on top of the SJOne board. The pins on the right of the board align right on top the SJOne board's I/O pins to allow for accessibility.
| [[File:S16 SoundBuddy PCB Top Bottom.png|300px|right]]
|}

=== Software Design ===
...ADD FLOWCHARTS HERE...

<BR/>

=== Hardware Implementation ===
==== Sender Board ====
==== Receiver Board ====
==== MP3 Decoder ====
[[File:S16 Sound Buddy PCB Top1.jpg|300px]]
<br>
[[File:S16 Sound Buddy PCB Bottom1.jpg|300px]]

=== Software Implementation ===
==== Sender Board ====
<syntaxhighlight lang="cpp">

Put code here!!!

</syntaxhighlight>
==== Receiver Board ====
<syntaxhighlight lang="cpp">

Put code here!!!

</syntaxhighlight>
==== MP3 Decoder ====
<syntaxhighlight lang="cpp">

Put code here!!!

</syntaxhighlight>

<br>
.............................................................................................NOTES..................................................................................................

=== Hardware Interface ===
In this section, you can describe how your hardware communicates, such as which BUSes used.  You can discuss your driver implementation here, such that the '''Software Design''' section is isolated to talk about high level workings rather than inner working of your project.

There are four hardware communication interfaces in the Sound Buddy: SD card reading; Nordic wireless transmission; I2C bus communication between the Receiver board and the Decode board.

'''SD Card Reading'''
The Sound Buddy reads the SD card using an SPI bus interface. The Sound Buddy will assume MP3 standard files are on the SD card. The rate at which the SD card is read is ???, this allows for reformatting of the data for transfer over the Nordic wireless communication link. 

'''Nordic Wireless'''
The maximum data transfer rate for the Nordic wireless is 250 Kbps. The Sound Buddy operates near this maximum. 

'''I2C Bus Communication'''
The I2C communication delivers, at minimum, 128 Kbps to the decode board. This means the Sound Buddy is capable of delivering radio quality sound.  Sound Buddy is capable of reading ITunes MP3 standard (256 Kbps) but play quality is limited to 128 Kbps.

=== Software Design ===
Show your software design.  For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level.  Do not show the details of the code.  For example, do not show exact code, but you may show psuedocode and fragments of code.  Keep in mind that you are showing DESIGN of your software, not the inner workings of it.






'''Writing to the Decode Board'''


[[File:S16_STA013_Software_Tasks.jpg‎ ]]

=== Implementation ===
This section includes implementation, but again, not the details, just the high level.  For example, you can list the steps it takes to communicate over a sensor, or the steps needed to write a page of memory onto SPI Flash.  You can include sub-sections for each of your component implementation.

===Nordic Wireless Communication===
<br>
[https://mcuoneclipse.com/2013/07/20/tutorial-ultra-low-cost-2-4-ghz-wireless-transceiver-with-the-frdm-board/  Nordic Wireless User Manual]
<br>
<br>

[http://blog.diyembedded.com/ Embedded Tutorials]
<br>

'''Nordic Wireless Transmission'''<br>
'''Step 1:''' Call the init function and set the device as a transmitter. <br>
'''Step 2:'''Check to make sure the FIFO is not full.  Do this using TX FIFO  (it is available in STATUS and FIFO_STATUS registers.)<br>
'''Step 3:'''Call the nrf2401_write_tx_payload() function. <br>
'''Step 4:'''Wait for the TX_DS interrupt to go active before sending another packet. <br>

*The transmitter should allow a 130usec delay if in Enhanced Shockburst mode, It may not be necessary in standard Shockburst. <br>

We use the nrf2401_power_up() and nrf2401_power_down() functions to conserve power. <br>

For debugging we use the nrf240`_get_all_registers() function. We pass it a 36 byte array and we can read every register in the 24L01. <br>
<br>
<br>
'''Nordic Wireless Receiver Mode - Using Interrupts and One Pipe'''<br>
'''Step 1:''' Call the init function and set the device as a transmitter. <br>
'''Step 2:'''CE must be high, after having been low. <br>
'''Step 3:'''Start monitoring packets 140 usec after the CE pin is set. <br>
'''Step 4:'''Using interrupt mode: call nrf2401_read_tx_payload() in the interrupt service routine. <br>
'''Step 5:'''After receiving the packet, clear the interrupts by calling one of these functions:<br>
 - nrf2401_irq_clear_rx_ds()<br>
 - nrf2401_irq_clear_all()<br>

<br>

===Data Packet  Configuration===
<br>
Since we are doing audio files and using the MP3 Decoder, we have a need for increased data transmission speeds and can accept high error rates.  Therefore the Sound Buddy uses the Shocburst data packet. 
<br>



<br>

===Nordic Wireless Instructions===
<br>
===STA013 Decoder Tasks===
<br><br>
'''Step 0:''' There must be a reset to the STA013 device. For the debug board we did a hard reset, for the final version this is sent from the Receiver board. 
<br>
<br>
'''Step 1:''' Check for the presence of the STA013, read from address 0x01.  There should be an ACK, then the data returned should be 0xAC.  These two data points mean the device is present and communicating properly. 
<br>
<br>Do a hard red of the board
<br>i2c discover -- shows all the i2c devices responding :0x38, 0x40, 0x86, 0x90
<br>i2c read 0x86 0x01 10
<br>We write :i2c read 0x86 0x01 10   -- this returns 0xAC for the first byte.  So we know the board is live. 

'''Step 2:''' Transmit  p02_0609.bin, which is supplied by ST. This file has 2007 address and data pairs. Do this by writing a loop that passes each pair to the sta013_write function. Each ACK should be checked and the process aborted if a write does not receive any of its ACLs.  If this step is not accomplished the STA013 may not operate properly. 
We may need to include a 0.6 ms delay after sta013_write if the address is 16. 

<br>i2c write 0x86 0x72 01
<br>


'''Step 3:''' Once the config file is sent, the board specific settings are sent. For a 14.7456 MHz crystal and a CS4334 DAC.  The easiest way to send these settings is by attaching them to the end of the bin file. (The bin file is actually an ASCII file with a .bin extension)

'''The Settings'''
<br> i2c write 0x86 54   1
<br>i2c write 0x86 55   21
<br>i2c write 0x86 7  0
<br>i2c write 0x86 6  c
<br>i2c write 0x86 b  3
<br>i2c write 0x86 50 10
<br>i2c write 0x86 51 0
<br>i2c write 0x86 52  4
<br>i2c write 0x86 61  F
<br>i2c write 0x86 64 55
<br>i2c write 0x86 65  55
<br>i2c write 0x86 5  A1
<br>i2c write 0x86 18  4

<br>RUN command  -- i2c write 0x86 0x72 01
<br>START PLAYING command -- i2c write 0x86 0x13 01



'''Step 4:''' Tell the STA013 to start operating. 
Do this by writing a ‘1’ to the address 114 (or 0x72) to tell the STA013 to start running, 
then a 1 to address 19 (or 0x13) to tell it to start playing. 
The  DATA_REQ pin should be asserted

When you start feeding in valid MP3 data, the chip detects the MP3 sample rate and creates the correct clock for the DAC and starts pushing data into it. 
The STA013 will ignore non-MP3 data so it is safe to send the entire file without needing to strip out ID3 tags, etc.
The STA013 expects the most significant bit first, which corresponds to the SPI standard.

[https://www.pjrc.com/mp3/sta013.html#doing_config STA013 User Manual]

== Testing & Technical Challenges ==

'''Proto-Type'''

[[File:S16_SoundBuddy_ProtoType.png|600px]]

Describe the challenges of your project.  What advise would you give yourself or someone else if your project can be started from scratch again?
Make a smooth transition to testing section and described what it took to test your project.

Include sub-sections that list out a problem and solution, such as:

=== My Issue #1 ===
Discuss the issue and resolution.

'''Nordic Wireless'''

Nordic Wireless Transmission Rates Too Low:<br>
Due to lower transmission rates, the Sound Buddy cannot use the provided software for the Nordic wireless. The provided software is designed for a Mesh Network, which does error checking in full duplex mode. Unfortunately, the transmission rate for the Enhanced Shockburst mode is too slow for audio file transmission.  Sound Buddy uses the standard Shockburst mode. This will lead to increased transmission speeds at the cost of loss of error checking.  This tradeoff is acceptable when dealing with audio files, as potentially dropping some packets will not greatly affect sound quality. 
<br><br>
'''Receiver Board'''

Testing The Receiver board - MP3 Decoder Communication:<br>
The receiver board is required to test the MP3 decoder. Our initial plan involved loading the SD card with a known MP3 standard file, reading the file byte by byte, then transmitting it to the MP3 decoder.  We had issues with using the same bus to read the SD card and transmit the data. 

Our issue is we believe the STA013 decoder is working properly. It is recognizing the data as MP3, generating the proper clocks, and sending data to the DAC. The DAC for some reason is not  responding to this data.

<br><br>
'''MP3 Decoder'''<br>
- Designing the PCB before checking out the debug board, led to a layout/part inconsistency. The MP3 Decoder was laid out using a different (smaller) foot print than the ordered part.<br>
We corrected this error by gently bending the legs of the IC so that they fit on the PCB.
<br>
Chip Select<br>
This has been a continuing concern -- the bit enable line on the MP3 decoder. We initially pulled it high, which set the chip to always enabled. We found this meant every time we accessed the SD card - data was available on the SDI bus. Since this is the bus on which the MP3 Decoder receives data, we believe this is causes the MP3 decoder to try decode this traffic. 

We have added a chip select to see if this will solve our problems.

Issues
* creating a nordic driver to send data
* buffer during data transfer to get max speed
* getting the mp3 decoder prototype to function

Tests
Nordic driver tests
* sending a byte over nordic to all of the receiver devices
* sending text file over nordic to all of the receiver devices
* sending and 4 MB MP3 file over nordic
* performance test to increase data transfer speed of Nordic
** changed buffer size
** changed data packet size
** changed priority of tasks

MP3 decoder tests
* initialize the decoder
* play sample MP3 file
* play an actual song over MP3

Integration
*Send and play an MP3 via nordic

== Conclusion ==
Conclude your project here.  You can recap your testing and problems.  You should address the "so what" part here to indicate what you ultimately learnt from this project.  How has this project increased your knowledge?

=== Project Video ===
Upload a video of your project and post the link here.

=== Project Source Code ===
*  [https://sourceforge.net/projects/sjsu/files/CmpE_S2016/ Sourceforge Source Code Link]

== References ==
=== Acknowledgement ===
Preet Kang, who taught us what we needed to know to use the SJOne board and FreeRTOS for our project.
<br>
...And humor. For without it, we would not be able to enjoy each other's presence during the completion of this project.
<br>
[[FILE:SP16_Sound_Buddy_Logo_2.jpg|200px]]

=== References ===
List any references used in project.
* Wiki Page Development
** <span class="plainlinks">[https://en.wikipedia.org/wiki/Help:List#Multi-column_bulleted_list Wiki Help List]</span>
** <span class="plainlinks">[https://en.wikipedia.org/wiki/Help:Link Wiki Help Link]</span>

* Project
** Nordic Wireless
***<span class="plainlinks">[http://www.socialledge.com/sjsu/index.php?title=Nordic_Low_Powered_Mesh_Network_stack Nordic Low Powered Mesh Network stack]</span>
** MP3 Decoder
***<span class="plainlinks">[https://www.pjrc.com/mp3/sta013.html How To Use The STA013 MP3 Decoder Chip]</span>