
Voice Activated Calculator Shuab Khan Siddharth Yereddi
Outline • Objectives • Design • Tests • Challenges • Conclusions
Why Voice Activated? • Convenient • Marketable Consumer Device • Way of the Future • Applications
Project Objectives • Speaker Independent • Performs Basic Calculations • Works in Natural Environment
Design • Pre-filter and Preamplifier • Speech analysis on Digital Signal Processor (DSP) • Calculations on PIC microcontroller • Output displayed on LCD
Microphone (Input) Analog Filter (90Hz – 5 kHz) Amplifier Gain Factor: 450 V/V Speech Detection and Recognition (DSP) Digital Filter (300Hz – 5kHz) (DSP) PIC Microcontroller LCD Display Realtime System
Preamplifier Test Measured Gain = 450 V/V
Prefilter Simulated Frequency Response 6 kHz [cutoff]
Anagrams • Spectrum ------> Cepstrum • Filtered ------> Liftered • Frequency ------> Quefrency
Issues on DSP • Memory limit • Overflow handling • Quantization Errors • Processing Time • Environment Noise Level
Future Developments • Floating Point DSP • External Memory Chip • Larger Training Data