Bluetooth Controlled High Power Audio Amplifier- Final Presentaion
Post on 02-Dec-2014
DESCRIPTIONFinal presentation for Minor Project completed by BEX Third year students of Thapathali Campus, IOE.
- 1. BLUETOOTH CONTROLLED HIGH POWER AUDIO AMPLIFIER Thapathali Campus Final Presentation 2013 PRESENTED BY: BIJAY RAJ PAUDEL (ROLL NO: 067/BEX/105)SAGAR MALI (ROLL NO: 067/BEX/133) SUJAN SHRESTHA (ROLL NO: 067/BEX/140)
2. INTRODUCTION Decent quality High Power Audio Amplifier 8051 Microcontroller based control Digital control over tone, effects & volume Wireless Bluetooth Interface Control via Computer Software/ Android software and/or Keypad 3. OBJECTIVES To construct cost effective high power audio amplifier. To implement 8051 c along with its interfacing. To control the system via wireless Bluetooth module. To program c & develop GUI based PC application. To improve our programming & practical skills. 4. PROJECT IN BLOCK DIAGRAM MAIN BOARD Audio Input 5. PROJECT IN BLOCK DIAGRAM CONTROLLING UNIT 6. BRIEF EXPLANATION OF EACH BLOCKBLOCK REPRESENTAION OF POWER SUPPLY 7. BRIEF EXPLANATION OF EACH BLOCK1. POWER SUPPLY 1.1. RECTIFIER 6A capacity bridge rectifier with +43 and -43 volt output With Electrolytic and Ceramic capacitor filer 5A fuse for protection 8. BRIEF EXPLANATION OF EACH BLOCK 1.2. VOLTAGE REGULATOR Based on LM337 (negative voltage regulator) and LM137 (positive voltage regulator) Conduction through Power transistors for increased current capacity. 9. BRIEF EXPLANATION OF EACH BLOCK 2. PRE AMPLIFIER 3 active filters( for bass, mid, treble) 2 op-amp amplifiers first before filter & next after filter for larger gain. Variable Gain controller In-built Distortion effect (achieved by diode clipping) 10. BRIEF EXPLANATION OF EACH BLOCK 3. DIGITAL VOLUME & TONE CONTROL Based on analogue multiplexers. (8x1 for bass, mid, treble and 16x1 for volume control) 11. BRIEF EXPLANATION OF EACH BLOCK 4. POWER AMPLIFIER Simulated for 80Watt output in Proteus, (power supply of +-30 V) 3 stage amplifierDifferential amplifier input (for gain) Voltage amplifier Power amplifier Output short circuit protection 12. BRIEF EXPLANATION OF EACH BLOCK 5. Bluetooth ModuleUses class C Bluetooth radio Uses SPP (Serial Port Protocol) for interface 4 pins for Vcc, Gnd, Txd and RxD Works at default baud rate of 9600 bauds Interface with 8051 microcontroller using UART Works at CMOS voltage level (3.3V, 0V) 13. BRIEF EXPLANATION OF EACH BLOCK 6. TTL CMOS level ConverterBluetooth works on CMOS level and microcontroller on TTL level so voltage level conversion is required.Achieved by using N-Channel Enhancement mode MOSFET Bidirectional operation (3.3V to 5V and 5V to 3.3V) Two similar circuits for TxD and RxD 14. COMPUTER GUI Codes in C# .NET Uses serial port class provided by .NET library User interface in WPF 15. BRIEF EXPLANATION OF EACH BLOCK 4. Main Controller Board8051 microcontroller based Interface with LCD in 8 bit mode Interface with EEPROM Interface with three 8x1 analogue multiplexers for bass, mid, and treble control and one 16x1 multiplexer for volume controlInterface with Bluetooth module 16. ALGORITHM FOR MAIN CONTROLLER 17. START Initialize LCDShow Welcome bass, mid, Volume & treble status Initialize Serial Port in mode1 and Set Timer 1 for 9600 baud in mode 2Set Timer 0 value and enable timer 0 interrupt Enable timer 0 and timer 1 While (1)Timer 0 Interrupt Update LCD with Bass, mid, treble and volumes current valueCheck interruptCSerial InterruptSI 18. SIYes CTI=0Is TI set?Check Keypad Pins No Increase/Decrease volume, bass, mid and treble Send data corresponding pins attached to multiplexers Send updated values to serial port(SBUF)No Is RI set?RI=0Yes Read SBUF serial port RI 0Update Vol, Bass, Mid Treble value as command received in SBUF Send data to corresponding pins attached to multiplexers 19. BRIEF EXPLANATION OF EACH BLOCK 4. KEYPAD 4*4 matrix keypad. 16 keys produce 16 different combinations to interface with the main controller Extra interrupt signal pin Backlight LEDs for low light operation 20. BRIEF EXPLANATION OF EACH BLOCK 5. KEYPAD CONTROLLER Separate Controller to scan keys to relieve main controller of input reading duties 8051 microcontroller based Accepts the input from keypad Outputs information to microcontroller at main board 21. ALGORITHM FOR KEYPAD CONTROLLER 22. STARTSimilar to other columns & rowsInitialize all ports to zero Output 5 to port 1 Is key pressed?Is R1=0?Yes Initialize all rows to 1 Initialize C2 =0 & other to 1 Initialize C1=0 other to 1 Similar to other rows R2 to R4 Is R1=0?Output 0 to port 1 23. PROBLEMSSOLUTIONS Using transistors in metal cases and larger heat sinksProper shielding of preamplifier and connecting wires Speaker over voltagespikes damaging the speaker under high volumesUse of filter output capacitor and output audio transformer(yet to be implementedUse of analogue mux, with lesser resolution but it does the job Overheating of power transistors Noise induction in preamplifier. Digital potentiometer not available 24. APPLICATIONS Auditorium Hall Seminar Presentation Lecture Theatrical and Concert sound reinforcement Home Theater System Car Audio System Guitar Amplification 25. PROPOSED BUT NOT IMPLEMENTED PARTS Limited effect is only implemented because of unavailability of effect IC and complex design if done using discrete components. Separate independent remote control with LCD Couldnt be implemented because of high cost of Bluetooth module. Making separate controller required another Bluetooth module working in Master mode.Bluetooth of laptop or android set is used as Master (Host). 26. EXTRA PARTS IMPLEMENTED Interface using Android devices (tablets and smart phones) High current capacity voltage regulator TTL-CMOS bidirectional voltage level converter 27. CONCLUSION Our final product is HIGH POWER AUDIO AMPLIFIER.Finally, it has its own GUI BASED CONTROL APPLICATION which can be operated through Bluetooth enabled windows based devices.Control via Android based smart-phones using serial terminal emulator for android (BlueTerm)We have build BLUETOOTH INTERFACE between system & digital control. 28. FURTHER ENHANCEMENT Multichannel audio output (2.0 ch, 5.1ch) Wireless audio input via Bluetooth. Increasing steps for tone and volume control. Development of control applications on other platform (iOS, Mac, Linux ) Other audio effects (Echo, delay, compression, reverb etc.) 29. REFERENCES BOOKS:A.S. Sedra and K.C. Smith, Microelectronics Circuits Theory and Application, 5th edition, Oxford University PressMuhammad Ali Mazidi, 8051 Microcontroller and Embedded Systems, Prentice Hall, 2006Douglas Self, Audio Power Amplifier. Design Handbook, 3rdedition. WEBSITES: http://hackaday.com/2011/06/27/stereo-amplifier-with-digital-volume-control/ http://www.diyaudio.com/forums/solid-state/ http://en.wikipedia.org/wiki/Bluetooth http://www.bluetooth.com/ http://www.aaroncake.net/circuits/volume.asp 30. THANK YOU FOR YOUR INTEREST!