Brian J. Crepeau (Kevin Austin), 2009
Development of a Miniature Binaural Recording Device for Ultrasonic Vocalizations of Big Brown Bats
The intent of this thesis was to develop a system to store bat vocalizations on a MicroSD media card. The design involves interfacing a MicroSD card and an analog-to-digital converter to a microcontroller. The frequency of a bat’s ultrasonic vocalization may be as high as 80 kHz. Thus, the minimum sampling rate is 160 kilosamples per second (ksps) and the serial data transfer rate (SDTR) for 16-bit samples is 2.56 megabits per second (Mbps). Development proceeded using a prototyping system that provided an SD card socket connected to a microcontroller and a “C” compiler. Initial tests demonstrated that the SD card drivers provided with the compiler achieved 0.74 Mbps. According to the device specification, SD cards support SDTRs up to 25 Mbps. Further investigation showed that the drivers utilized an inefficient write mode that required the driver to delay writing the next block after each 512 byte block was transferred. It was discovered that SD cards support a mode that allows multiple blocks to be written using a single command. Transfer efficiency is improved by separating each 512-byte block with a one-byte start token, instead of waiting and then repeating the 6-byte single-block write command. Replacement drivers developed using the multiple-block write mode achieved an SDTR of 1.92 Mbps, which can be further improved by increasing the microcontroller’s clock speed. This work shows that storing analog samples at 160ksps on an SD card is possible if the microcontroller clock speed is increased and efficient device drivers are provided. Engineers should be prepared to write their own device drivers to meet design specifications as the device drivers delivered with compilers may have performance issues in demanding applications.
James Lang (Natasha Kurtonina), 2006
The Little Networking Helper
Many people use computer networks every day without truly understanding how they work, however a basic knowledge of their functioning would allow people to make better informed decisions about their own home or business networks when purchasing new hardware, connecting to the internet or talking with their information technology staff. To increase people’s understanding of their computer networks, the current paper discuses the basics of how a computer network works from the physical connections to the computer interpretation of the data and the inner workings of the World Wide Web. Accompanying the paper will be an illustrated booklet that will first describe various aspects of computer networks, comparing and contrasting different Information Technologies, followed by a glossary of common computer network terms. With this information readers will have the tools to make more informed decisions about their own computer networks.