AUDIO SPECTRUM ANALYZER
Transcript of AUDIO SPECTRUM ANALYZER
AUDIO SPECTRUM ANALYZER
Tuna ŞAHİN
Undergraduate Project Report Submitted in partial fulfillment of
The requirements for theDegree of Bachelor of Science (B.S.)
In
Electrical and Electronic Engineering DepartmentEastern Mediterranean University
January 2014
ABSTRACT
AUDIO FREQUENCY ANALYZER
By
Tuna ŞAHİN
Electrical and Electronic Engineering DepartmentEastern Mediterranean University
Supervisor: Prof. Dr. Runyi YUSupervisor: Assoc. Prof. Dr. Erhan A. İNCE
Keywords: Audio Frequency, Frequency Analyzer, Leds, Filter,
An audio frequency analyzer is a type of animated light for entertainment purposes that creates an aesthetic design. These leds are lighting with respect to sound frequencies. These leds can be chosen any numbers and any colors as our wish also audio frequency sensivities can be expanded much more.
In this project, design and construction an audio frequency analyser with
microcontroller.
Acknowledgments
This study is a final year project proposal for Department of Electrical and Electronic
Engineering, Eastern Mediterranean University. The project is about design and
construction of audio frequency analyzer. We mainly thank to Prof. Dr. Runyi Yu and
Assoc.Prof. Dr. Erhan A. İNCE for sharing his knowledge and experiences with me in the
process of completing my project.
Table of Contents
ABSTRACT..........................................................................................................................I
ACKNOWLEDGMENTS...................................................................................................II
TABLE OF CONTENTS...................................................................................................III
LIST OF FIGURES...........................................................................................................IV
LIST OF TABLES..............................................................................................................V
1. INTRODUCTION............................................................................................................1
2. .DESIGN FREQUENCY ANALYZER WITH MICROCONTROLLER......................2
2.1 METHODOLOGY.................................................................................................2
2.1.1 ARDUINO MICROCONTROLLER.............................................................2
2.1.2 LM3915 VU METER.............................................................................3
2.1.3 MSGQE7............................................................................................4
2.1.4 NARROW BANDPASS FILTER............................................................6
2.1.5. HIGH LEVEL DESIGN.........................................................................7
2.2 ENGINEERING STANDARDS..........................................................................8
3. TIME PLAN...................................................................................................................10
4. COST ANALYSIS.........................................................................................................11
5. CONCLUSION..............................................................................................................12
List of Figures
Figure 1: Arduino Uno R3 microcontroller for time delay……………………………….2
Figure 2: Circuit of LM3915 Vu meter…………………………………………………...3
Figure 3 : Block diagram of MSGQE7................................................................................4
Figure 4 : Narrow Bandpass Filter.....................………………………………………….5
Figure 5 : High Level Design..............................................................................................6
List of Tables
Table 1 : Time Plan…………………………………………………………………..10
Table 2 : Cost Analysis……………………………………………………………….11
1. Introduction
This project is about design a circuit for lighting leds which sensitive to audio with
frequency detection and db level of audio.
Our final project is a musical lighting for visual feast to use in the entertainment
industry. The basic idea of the project is to take an input from an iPod (or any sound source),
sample the sound and break it down to different frequencies, and then use the output to
turn on leds. We will first use a seven-stage bandpass filter or integrated circuit (msqeq7), on
the sound source to split the sounds into different frequency ranges. Each different range will
correspond to a different db levels and we will detect it using circuit (Lm3915) and after
detection, provide synchronization with ardunio microcontroller.
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2. Design Frequency Analyzer with Microcontroller
2.1 Methodology
2.1.1 Arduino Microcontroller
Arduino is a tool for making computers that can sense and control more of the physical
world than your desktop computer. It's an open-source physical computing platform based on
a simple microcontroller board, and a development environment for writing software for the
board.
Arduino can be used to develop interactive objects, taking inputs from a variety of
switches or sensors, and controlling a variety of lights, motors, and other physical outputs.
Arduino projects can be stand-alone, or they can be communicating with software running on
your computer (e.g. Flash, Processing, MaxMSP.) The boards can be assembled by hand or
purchased preassembled; the open-source IDE can be downloaded for free. The Arduino
programming language is an implementation of Wiring, a similar physical computing
platform, which is based on the Processing multimedia programming environment.
Why do we use Arduino?
First of all I have chosen Arduino Uno R3. Because it has maximum output per
channel. Also Arduino is the smartest card from the others. I use the Arduino Uno R3 for
time delay operation with musical lighting leds.
Figure 1 : Arduino Uno R3 microcontroller for time delay
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2.1.2 LM3915 Vu Meter
The LM3915 is a monolithic integrated circuit that senses analog voltage levels and
drives ten LEDs, LCDs or vacuum fluorescent displays, providing a logarithmic 3 dB/step
analog display. One pin changes the display from a bar graph to a moving dot display. LED
current drive is regulated and programmable, eliminating the need for current limiting
resistors. The whole display system can operate from a single supply as low as 3V or as high
as 25V. The IC contains an adjustable voltage reference and an accurate ten-step voltage
divider. The high impedance input buffer accepts signals down to ground and up to within
1.5V of the positive supply. Further, it needs no protection against inputs of ±35V.The input
buffer drives 10 individual comparators referenced to the precision divider. Accuracy is
typically better than 1 dB. The LM3915's 3 dB/step display is suited for signals with wide
dynamic range, such as audio level, power, light intensity or vibration. Audio applications
include average or peak level indicators, power meters and RF signal strength meters.
Replacing conventional meters with an LED bar graph results in a faster responding, more
rugged display with high visibility that retains the ease of interpretation of an analog display.
The LM3915 is extremely easy to apply. A 1.2V full-scale meter requires only one resistor in
addition to the ten LEDs. One more resistor programs the full-scale anywhere from 1.2V to
12V independent of supply voltage. LED brightness is easily controlled with a single pot. The
LM3915 is very versatile. The outputs can drive LCDs, vacuum fluorescents and
incandescent bulbs as well as LEDs of any color. Multiple devices can be cascaded for a dot
or bar mode display with a range of 60 or 90 dB. LM3915s can also be cascaded with
LM3914s for a linear/log display or with LM3916s for an extended-range VU meter.
Figure 2 : Circuit of LM3915 Vu meter
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2.1.3 MSGQE7
Description: The seven band graphic equalizer IC is a CMOS chip that divides the
audio spectrum into seven bands. 63Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6.25kHz and 16kHz.
The seven frequencies are peak detected and multiplexed to the output to provide a DC
representation of the amplitude of each band. No external components are needed to select
the filter responses. Only an off chip resistor and capacitor are needed to select the on chip
clock oscillator frequency. The filter center frequencies track this frequency.
Other than coupling and decoupling capacitors, no other external components are
needed. The chip supply can be between 2.7 and 5.5 volts with 5 volts providing the best
performance. The device has very low quiescent current (less than 1ma typical) for portable
audio devices. the multiplexer is controlled by a reset and a strobe, permitting multiplexer
readout with only two pins. The multiplexer readout rate also controls the decay time (10%
decay per read), so no external pins are needed for this f
Features:
Low Power Consumption
Only Two External Components
On Chip Ground Reference
Switched - Capacitor Filters
3.3 or 5 Volts Operation
20 dB of Gain
On Chip Oscillator
Output Multiplexer
Variable Decay Time
8 Pin DIP Package
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Block diagram
2.1.4 NARROW BANDPASS FILTER
Narrow bandpass filters are designed to isolate a narrow region of the infrared
spectrum. This is accomplished using a complex process of constructive and destructive
interference.
Narrow band pass filters have bandwidths (measured at half-peak transmittance
levels) less than 6% of the center of wavelength value. When ordering, the bandwidth can be
expressed as a percentage of the center wavelength, or can be given in microns.The filters
exhibit high peak transmission (typically greater than 60%) combined with high attenuation
levels outside the passband (typically less than 0.1%)
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2.1.4 High Level Design
Currently, there are several ways to design this project but first, I want to
mention the most critical section of the project. As you see in the above figure there
are 7 levels leds on the x- axis and 3 levels leds on y-axis but we can put up to 10
levels on y-axis. On the horizontal axis we will use msqe7 or we will design 7 narrow
bandpass filter to detect and divide frequency 7 level .If we use filter we can increase
this level but on msgqe7 ,we have max 7 level. On the vertical axis we will use
Lm3915 to detect power of the source (db). Design of this project is that how to
synchronize after detect db and frequency, get a correct flow according to random
source. We will use Arduino microcontroller and pic programming to synchronize
them. Mainly we have 2 different designs on this project one of them designing filter
other one is design the circuit and synchronize them.
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2.2. Engineering Standards
IEEE Code of Ethics:
1. To accept responsibility in making decisions consistent with the safety, health and
welfare of the public, and to disclose promptly factors that might endanger the public or
the environment;
Given that my project involves electricity, I will take very careful concern on safety
and health issues. I make sure anyone working near or on my project realize the risks
associated with it, and are extremely careful when standing near my project during actual
execution.
.
2. To reject bribery in all its forms;
I accepted no bribes.
3. To improve the understanding of technology, its appropriate application, and
potential consequences;
I specifically chose this project despite a lack of knowledge in how to design a circuit
to get our aim. Using the internet and expert resources, I will learn everything I need to know,
and sometimes even applied the knowledge in a different way to complete my project. I
purpose fully stepped out of our comfort zone in order to complete this project.
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TIME PLAN
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4. COST ANALYSIS
The expected cost for all of the materials used in the study is given below
TYPE OF MATERIAL NUMBER MATERIAL COST
Arduino Uno R3 Microcontroller 1 65 TL
MSQEQ7 2 50 TL
Vu meter (LM3915) 2 8 TL
LM741 Operational Amplifier 4 2 TL
12 V Power Supply 1 10 TL
5 V Power Supply 1 10 TL
Plastic Box 1 5 TL
CD407 2 8 TL
Led Lights 100 175 TL
Resistance 10 15 TL
With information of price ranges above, total expected cost will be about 348 TL.
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5. CONCLUSION
In this project, design and construction audio frequency analyzer with using a
microcontroller explained. First, importance of audio frequency analyzer is described. Then,
design step and methodology are mentioned. Moreover, I gave some information about and
working principle of audio frequency analyzer. The required time plan and cost analysis are
performed for design of audio frequency analyzer with using a microcontroller. During the study
period of project, sufficient experience has been gained for the implementation of the audio
frequency analyzer with using a microcontroller.
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6. REFERENCES
[1] Arduino Official Web Page. (January 03, 2010). Arduino RV3. Retrieved (Dec 09, 2013), from the World Wide Web: http://arduino.cc/en/Guide/Introduction
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