230 likes | 537 Views
Spectrum Analyzer. Ray Mathes, Nirav Patel, Sagar Savant, Richard Wunderlich Group 8, ECE4006D Georgia Institute of Technology School of Electrical and Computer Engineering. Project Overview.
E N D
Spectrum Analyzer Ray Mathes, Nirav Patel, Sagar Savant, Richard Wunderlich Group 8, ECE4006D Georgia Institute of Technology School of Electrical and Computer Engineering
Project Overview A Spectrum Analyzer that synthesizes audio input from the computer and outputs it as a physical spectrum. • Input: MP3, Wave-Input, Microphone • Output: Water Jets representing spectral frequencies. • Features • Tunable to frequency ranges to increase bin resolution • Real-Time Response Group 8 - Spectrum Analyzer, 2
Design Layout Computer Pump Array Power Supply Audio P1 Winamp Altera Board P2 UP2 Input MAX7000 Chip PWM Logic Switching Circuit … FFT Plugin P15 P16 Paralell Port Group 8 - Spectrum Analyzer, 3
Software • Winamp • Generates signal vector from MP3, Wav, etc. • Creates a 256 bit amplitude stored in an array according to frequency channel. Group 8 - Spectrum Analyzer, 4
Computer Audio Winamp FFT Plugin Paralell Port Software (cont.) • Winamp Plugin • Convert the amplitude into 3 bits by chopping off the lower 253 bits. • Divide up the frequencies into usable bins of 16 for each pump address, 4 Bits. • Allow for variation of frequency range • Use API Calls for the Parallel Port to send pump address and data bits to the Altera board. Group 8 - Spectrum Analyzer, 5
Altera Board UP2 Input MAX7000 Chip PWM Logic Hardware • Want a visually variable amplitude • Varying speed of pump varies flow rate • Flow rate determines height of water jet • Solution • DC Motors vary speed with input voltage • Easiest way to achieve this digitally is through Pulse Width Modulation (PWM) Group 8 - Spectrum Analyzer, 6
Pulse Width Modulation • A PWM signal is a pulse train with varying duty cycles If the frequency of the input voltage is too high, the motor cannot turn on and off fast enough. By modifying the duty cycle, PWM reduces the voltage to the pump. Group 8 - Spectrum Analyzer, 7
7 Bit Input • Want 8 steps of resolution in the height • Sending 3 bits of amplitude data per pump: 3*16 = 48 bits • Requires too large of a bus for parallel interface • Solved through Addressing • Send 3 bits for amplitude and 4 bits address data (7 bits total). Requires 16 calls from the Parallel Port to update every pump • Logic continues generating PWM on each output channel until updated again. Group 8 - Spectrum Analyzer, 8
Logic • 16 channels of PWM generation logic • Amplitude and address decoding logic Would require a large quantity of ICs and discrete logic to implement. Solution: FPGA Group 8 - Spectrum Analyzer, 9
FPGA • Altera UP-2 Board • FLEX10K70 FPGA, 70,000 gates. Loses memory when powered off. • MAX7000 CPLD, 2,000 gates. Maintains chip logic and memory. Group 8 - Spectrum Analyzer, 10
UP2 Board Output • 16 output pins produce controllable PWM signals for each pump • An output of 5V at 10 mA of current is insufficient. Group 8 - Spectrum Analyzer, 11
Switching Circuit Chopper Circuit • Purpose: Turn pumps on/off (Variable amp.) • Components • Darlington Transistor: Cascaded BJTs for current amplification • Diode: Assist motor to discharge stored current • Benefits: High current amplification Group 8 - Spectrum Analyzer, 12
Pump Array P1 P2 … P15 P16 Attwood V500 Water Pumps • Characteristics • DC powered, low power consumption (1.2A, 12V) • Benefits • DC pumps reduce cost, powerful, amplitude control • Shoots water up to 3 feet in the air without a nozzle, 350GPH Group 8 - Spectrum Analyzer, 13
Attwood V500 Water Pumps (cont.) • Problems with solenoids • Too Expensive • Don’t move very far (5 inches) • Overheating problems • Water Pump Array • 16 pumps at maximum flow rate require a lot of current Group 8 - Spectrum Analyzer, 14
Power Supply Power Supply Specifications • High Current Supply • ~ 240 Watts (12V 20A) • 16 pumps; each pump draws 1.2A max • I = 16*1.2 = 19.2A • Ferroresonant Transformer • PWM used to obtain correct voltages • Using a 10,000uF 80V filter capacitor Group 8 - Spectrum Analyzer, 15
Power Supply Design 12V/20A/240W AC to DC converting Power Supply. Group 8 - Spectrum Analyzer, 16
Design Challenges • Research absorbed a great deal of time • Ordering parts is too slow of a process • Need for power supply • Incapable of testing pumps safely in any lab Group 8 - Spectrum Analyzer, 17
Future Development • Pumps • Greater number of pumps to increase resolution • More powerful pumps for higher amplitudes • Remove the computer element • Input an audio jack • Use a DSP processor to do frequency tuning similar to the Winamp plugin • Design a structure to allow for indoor use Group 8 - Spectrum Analyzer, 18
Final Timeline • April 18 • Finish power supply • April 22 • Finish Winamp plugin and fine tune the characteristics • Build encasement for Altera board, power supply, and switching circuit • April 27 • Complete webpage: http://4006.iceglow.com • April 29 • Present Final Demo Group 8 - Spectrum Analyzer, 19
Questions? Group 8 - Spectrum Analyzer, 20