AUDIO SPECTRUM ANALYZER

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  1. 1. AUDIO SPECTRUM ANALYZER Tuna AHN Undergraduate Project Report Submitted in partial fulfillment of The requirements for the Degree of Bachelor of Science (B.S.) In Electrical and Electronic Engineering Department Eastern Mediterranean University January 2014
  2. 2. ABSTRACT AUDIO FREQUENCY ANALYZER By Tuna AHN Electrical and Electronic Engineering Department Eastern Mediterranean University Supervisor: Prof. Dr. Runyi YU Supervisor: Assoc. Prof. Dr. Erhan A. NCE 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.
  3. 3. 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. NCE for sharing his knowledge and experiences with me in the process of completing my project.
  4. 4. 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 ENGINEERINGSTANDARDS............................................................................8 3. TIME PLAN ..................................................................................................................10 4. COST ANALYSIS.........................................................................................................11 5. CONCLUSION..............................................................................................................12
  5. 5. 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
  6. 6. List of Tables Table 1 : Time Plan..10 Table 2 : Cost Analysis.11
  7. 7. 1 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.
  8. 8. 2 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
  9. 9. 3 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
  10. 10. 4 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
  11. 11. 5 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%)
  12. 12. 6 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 lev