Semester

Summer

Date of Graduation

2011

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

David W. Graham.

Abstract

The applications of Wireless Sensor Networks have grown exponentially over the last several years. These networks help to monitor environmental parameters such as temperature, humidity, pollution, motion, acoustics, and vibration in a variety of different ways. Each node (mote) in the network typically contains the following: a microprocessor, sensors, circuits that interface sensors with the mote, a radio transceiver, and a power source; typically a battery.;These sensor networks typically work by having the mote's Analog-to-Digital Converter (ADC) convert raw analog sensor data into digital, so processing can be done by the mote's microprocessor. If an event of interest has occurred, the mote transmits relevant data using its radio. However, if the data being read by the sensors are not of interest, the power consumed by the processor and ADC is wasted. This valuable energy is being used because of the mote's need to operate off of battery power.;Presented in this work are several analog systems with the ability to use Analog Signal Processing (ASP) prior to sending an interrupt to a higher level system. The first system is modeled on work previously conducted by Brandon Rumberg, and is used as a spectral analysis wake-up system. This system is used to detect programmable frequency content. If the content matches a predetermined template, an interrupt is given and the mote is awakened from its sleep state. The second system discussed is a biologically inspired vision system. This system uses ASP to detect objects moving. If the object is moving in a programmable speed range, an interrupt is given and the mote will awaken from its sleep state. The third system is a redesigned version of the biologically inspired vision system. The new system detects motion similarly to the previous system, however it has the ability to detect object speed as well as direction.;The ability to use ASP to pre-process the event before mote wake-up makes these two systems extremely important. By doing such, energy is saved and higher level processing is still possible once the information is converted into its digital form by the mote.

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