S15: MP3 Player with Graphic Equalizer Display - Revision history

146 user2: /* Mp3 Player */ quality control

2015-05-26T05:12:28Z

‎Mp3 Player: quality control

146 user2: /* Hardware Design */ -excess whitespace

2015-05-26T05:09:43Z

‎Hardware Design: -excess whitespace

Preet: /* Grading Criteria */

2015-05-26T04:46:29Z

‎Grading Criteria

146 user2 at 04:02, 26 May 2015

2015-05-26T04:02:24Z

146 user2: /* Schedule */

2015-05-26T01:26:44Z

‎Schedule

146 user2: /* Conclusion */ grammar/less wordy

2015-05-26T00:36:40Z

‎Conclusion: grammar/less wordy

146 user2: /* References */ add link to the 2012 project we referenced

2015-05-25T21:55:13Z

‎References: add link to the 2012 project we referenced

146 user2: /* Design & Implementation */

2015-05-25T21:48:54Z

‎Design & Implementation

146 user2: /* Conclusion */ grammar

2015-05-25T21:46:45Z

‎Conclusion: grammar

146 user2: /* Issue #1: Programming LED matrix */

2015-05-25T21:44:56Z

‎Issue #1: Programming LED matrix

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 ====Mp3 Player====
-Our focus in this project wasn't on the the Mp3 Player but rather on the whole system, a player with LED equalizer display. Therefore our player is rather simple, it run on FreeRTOS and consists of one task will read a song list from a text file then put song names into a vector. After that, it just reads the file in order then sends to the audio decoder to decode and output sound to a speaker and the equalizer analyzing circuit. This has very big room for further development; for example, we originally plan to have a communication between the player and a remote control, however, due to time constraint, we couldn't get it to work. With all that being said, with FreeRTOS, we can schedule and synchronize tasks to do different jobs on realtime. So having other tasks to communicate with a remote control and control the player accordingly is a possible improvement.
+Our focus in this project was on the whole system, an MP3 player with LED equalizer display. The system runs on FreeRTOS, reads a song list from a text file, and adds song names into a vector. Afterwards, the system reads the files in order, then sends to the audio decoder to decode and output sound to a speaker and the equalizer analyzing circuit. This accommodates further development; for example, we originally planned to establish communication between the player and a remote control but were precluded by time constraints. With FreeRTOS, we can schedule and synchronize tasks to do different jobs on realtime. So having other tasks to communicate with a remote control and control the player accordingly is a possible improvement.
 Pseudo code for Mp3_Player task:

← Older revision		Revision as of 05:09, 26 May 2015
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	Initially, we planned on outputting the audio frequency spectrum on a 16-by-32 LED matrix, with connections shown in Figure 3 in which two LPC1758's would be connected by UART, then the LPC1758 interfaced with the matrix via GPIO connections. However, we could not implement this part and decided on an alternative design (see Problem #1 section below).		Initially, we planned on outputting the audio frequency spectrum on a 16-by-32 LED matrix, with connections shown in Figure 3 in which two LPC1758's would be connected by UART, then the LPC1758 interfaced with the matrix via GPIO connections. However, we could not implement this part and decided on an alternative design (see Problem #1 section below).
−
−

	=== Hardware Interface ===		=== Hardware Interface ===

← Older revision		Revision as of 04:46, 26 May 2015
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−	~~== 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>~~
−
	== Abstract ==		== Abstract ==
	The [[SJ One Board]], which contains an LPC1758 microcontroller, will play MP3 audio files from an SD card and display the audio frequencies on a graphic equalizer simulated by LED's, an MP3 audio decoder integrated circuit (VS1053), and equalizer analyzing IC (MSGQE7).		The [[SJ One Board]], which contains an LPC1758 microcontroller, will play MP3 audio files from an SD card and display the audio frequencies on a graphic equalizer simulated by LED's, an MP3 audio decoder integrated circuit (VS1053), and equalizer analyzing IC (MSGQE7).

← Older revision		Revision as of 04:02, 26 May 2015
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	== Conclusion ==		== Conclusion ==
		+	[[File:S15_146_Gr2_Final.png\|thumb\|center\|650px\|Figure 6. Final Design of the mp3 circuit]]
	An MP3 player is an embedded system because within a greater electrical system, the player has the express purpose of opening MP3 audio files and outputting the audio frequency via LED's, through a graphic equalizer circuit. The LPC1758 microcontroller uses SPI bus to communicate with the MicroSD card to read the audio file and VS1053 audio decoder, which then outputs to a seven-band graphic equalizer MSGEQ7 that splits the audio into several bands of varying frequencies, as well as to a speaker system. Rows of LED's display the filter levels of each band. Programming the audio decoder involves resetting the hardware, then setting proper registers (mode, bass/treble, clock, etc.) for sound levels and data. Sending a song to the decoder sends the title and other relevant metadata to a vector.		An MP3 player is an embedded system because within a greater electrical system, the player has the express purpose of opening MP3 audio files and outputting the audio frequency via LED's, through a graphic equalizer circuit. The LPC1758 microcontroller uses SPI bus to communicate with the MicroSD card to read the audio file and VS1053 audio decoder, which then outputs to a seven-band graphic equalizer MSGEQ7 that splits the audio into several bands of varying frequencies, as well as to a speaker system. Rows of LED's display the filter levels of each band. Programming the audio decoder involves resetting the hardware, then setting proper registers (mode, bass/treble, clock, etc.) for sound levels and data. Sending a song to the decoder sends the title and other relevant metadata to a vector.

@@ Line 49: / Line 49: @@
 ! scope="row"| 1
 | 4/18
-| Order all hardware
+| Order all hardware.
 | Completed.
 |-
 ! scope="row"| 2
 | 4/25
-| Interface LED matrix with LP1758.
+| Interface LED matrix with LPC1758.
-Play a single MP3/Audio file
+Play a single MP3/Audio file.
-| Completed
+| Completed.
 |-
 ! scope="row" | 3
 | 5/1
 | Finish MP3 driver.
-| Completed
+| Completed.
 |-
 ! scope="row" | 4

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 == Conclusion ==
-An MP3 player is an embedded system because within a greater electrical system, the player has the express purpose of opening MP3 audio files and outputting the audio frequency via LED's, through a graphic equalizer circuit. The LPC1758 microcontroller uses SPI bus to communicate with the MicroSD card to read the audio file and VS1053 audio decoder, which then outputs to a seven-band graphic equalizer MSGEQ7 that splits the audio into several bands of varying frequencies, as well as to a speaker system. Rows of LED's display the filter levels of each band.
+An MP3 player is an embedded system because within a greater electrical system, the player has the express purpose of opening MP3 audio files and outputting the audio frequency via LED's, through a graphic equalizer circuit. The LPC1758 microcontroller uses SPI bus to communicate with the MicroSD card to read the audio file and VS1053 audio decoder, which then outputs to a seven-band graphic equalizer MSGEQ7 that splits the audio into several bands of varying frequencies, as well as to a speaker system. Rows of LED's display the filter levels of each band. Programming the audio decoder involves resetting the hardware, then setting proper registers (mode, bass/treble, clock, etc.) for sound levels and data. Sending a song to the decoder sends the title and other relevant metadata to a vector.
 With this project, we developed skills in communication, division of labor, and time management. We have gained experience in using FreeRTOS as a platform for our further development in realtime system. Especially with this project, we learned more about using SPI bus to communicate between devices.
-One of the advice for future students those go into this type of project is learn how to do the basic things first; we must always try to learn and build things from scratches, not to depend on existing libraries. So that when an issue emerges, we will always be able to trace back to the root of the problem and troubleshoot it. Especially, controlling an LED matrix will take some effort to learn how to control each and every row, column, and the colors of it. When one can fully know how to do it, it shouldn't be too much of a problem to display anything on the LED. As for the MP3 Player, using FreeRTOS to implement the player is a very good and efficient way to do, further implementation of this project could be creating tasks that will perform different jobs; for example, read a file, send data to the audio decoder, read data from the equalizer circuit, display through the LED, communicate with a remote control through the IR receiver... We just need to learn to FreeRTOS to schedule and synchronize tasks.
+Future students who wish to pursue this type of project should learn the basics first; we must always try to learn and build things from scratch, not depend on existing libraries. This is because when an issue emerges, we will always be able to trace back to the root of the problem and troubleshoot it, from original work. Controlling an LED matrix will take some effort to learn how to control each and every row, column, and the colors of it. Using FreeRTOS to implement the MP3 player is a highly efficient method; further implementation of this project could be creating tasks that will perform different jobs like reading a file, sending data to the audio decoder, or reading data from the equalizer circuit.
 === Project Video ===

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 === References ===
-*A. Dumbre, C. Vaidya, and K. Beadle. (2014). [[S14: Spectrum Analyzer for Audio Frequency Signals]].
+*A. Dumbre, C. Vaidya, and K. Beadle. (2014). ''[[S14: Spectrum Analyzer for Audio Frequency Signals]]'' [Online].
 *R. Huisinga. (1996). ''Equalizer'' [Online]. Available: http://web.archive.org/web/20100112045434/http://www.soundinstitute.com/article_detail.cfm/ID/110
 *Mixed Signal Integration. (2004). ''Seven Band Graphic Equalizer Data Sheet'' [Online]. Available: http://www.keil.com/dd/docs/datashts/philips/lpc17xx_um.pdf
 *NXP. (2010). ''UM10360 LPC17xx User Manual'' [Online]. Available: https://www.sparkfun.com/datasheets/Components/General/MSGEQ7.pdf
 *VLSI Solution. (2014). ''VS1053b Datasheet'' [Online]. Available: http://www.vlsi.fi/fileadmin/datasheets/vs1053.pdf

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 The two main components of the equalizer circuit were the audio jack and MSGEQ7 chip. The audio jack divides the audio into two audio channel, left and right. The left and right audio each go into the audio input of two seperate MSGEQ7. The MSGEQ7 is an audio spectrum analyzer chip with seven band-pass filters from 63 Hz to 16,000 Hz. Two MSGEQ7 chips were used to drive 2x5 LEDs. The MSGEQ7 is controlled with two digital signals, RESET and STROBE. A positive RESET signal is needed in order to start operation. The values of each of the bands can be read whenever seven negative pulses are inputted into STROBE. The values of the seven bands are analog values that are fed into an analog-to-digital converter (ADC) of two LPC1768. The ADC provides an us with a value between 0-4096 since the ADC resolution is 12-bit. The values from the ADC were divided by 40.96 in order to produce a value between 0 and 100. This new value is used in the pulse-width modulation in order to control the brightness of the 2x5 LEDs.
-[[File:S15 146 G2 LEDMatrixSchematic.png|thumb|450px|Figure 3. Schematic of proposed LPC1758/LED matrix interface.]]
+[[File:S15 146 G2 LEDMatrixSchematic.png|thumb|450px|Figure 3. Schematic of proposed LPC1758/LED matrix interface. (Source: Dumbre, Vaidya, and Beadle)]]
 Initially, we planned on outputting the audio frequency spectrum on a 16-by-32 LED matrix, with connections shown in Figure 3 in which two LPC1758's would be connected by UART, then the LPC1758 interfaced with the matrix via GPIO connections. However, we could not implement this part and decided on an alternative design (see Problem #1 section below).

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 === Issue #1: Programming LED matrix ===
-Our original plan was to output graphic equalizer via a 16-by-32 LED matrix. However, the matrix's library [https://learn.adafruit.com/32x16-32x32-rgb-led-matrix/library was intended for Arduino], and we could not find a way to port the library to the LPC1758. In the end, we decided to output the graphic equalizer via five LED's on a breadboard, instead. We advise future aspiring engineers to research about available libraries or ask an expert before attempting to interface hardware with a microcontroller.
+Our original plan was to output graphic equalizer via a 16-by-32 LED matrix. However, with the method we used to connect the matrix to the SJ Board GPIO pins, we could not light up the matrix interfaced with the board. In the end, we decided to output the graphic equalizer via five LED's on a breadboard, instead. We advise future aspiring engineers to research about available libraries or ask an expert before attempting to interface hardware with a microcontroller.
 === Issue #2: Additional PWM signal ===