Acoustic Navigation for Mobile Robots Computer System Design

Acoustic Navigation for Mobile Robots Computer System Design Spring 2003

Current Status • We are currently conducting breadboard testing and circuit analysis with individual subcomponents of the design • We are on schedule but are beginning to run into some unexpected problems.

Current Design

Deviations from Proposal • Addition of an adjustable filter controlled by a microcontroller • Switched microphone sampling control to microprocessor • Now have 8 frequency bands to select from • Went from a 4 -bit to an 8 -bit A/D

Microphone Array • Separate PCB for increased modularity and function • Implementing Plexiglass frame for Sound Dampening and increased directionality. • Have created the circuit/pcb design in Eagle 4. 0, currently investigating etching facilities.

Signal Rectification

Adjustable Filter Addition • Dual Switched Capacitor Filter • In conjunction with an oscillator, counters, and a multiplexor, design offers multiple frequencies to be polled at the microprocessors request. • Allows for more variability of the sensor system for future expansion into the communications realm.

Ideal Transfer Function

Newly Encountered Problems • Oscillator causes drastic noise leaving the microphone signal to be almost indistinguishable • Have not been able to get the filter to function as expected • Original Panasonic microphones do not react to sound sources at distances much greater than 6 -12 inches

Possible Solutions • Working filter ought to clean up the microphone signal noise caused by oscillator • Plan to preamplify the microphone signals for better sensitivity

Schedule