BT Consortium

Projects by Sean Breheny and Anish Trivedi



Photo of a test of thrust vectoring for an Aerotech G40 solid-fuel rocket motor. (The loud volume associated with this going off in my backyard brought out the next-door neighbor to see what happened!)

Introduction

Last updated April 14, 2001

I (Sean) have always been interested in science-related projects, especially those related to vehicles and radio or radar. When I went to high school, I met Anish Trivedi, who shared many of the same interests. From then until now (I'm a graduate student in electrical engineering, he's a n electrical engineer for Motorola), we have worked on a number of cool projects focusing on model rocketry and radar. This web site (which is far from being completed) is about these projects. It carries the name we jokingly gave to ourselves (as if we were in charge of a large corporation), BT Consortium, which is a "company" dedicated to producing such little demonstrations of engineering.

Radar Projects

We've currently completed one radar-related project (a small hand-held Doppler radar) and are working on another, the "BT/WSR-2002", an amateur-radio based weather radar operating at 3.5GHz, which will run on my callsign (KA3YXM). You can see the results of the completed one below. You can also see the progress on the BT/WSR-2002 project here.

Small Doppler Radar Experiment

This is a project using an M/A Com 10GHz Gunnplexer and an op-amp based audio amplifier to make a little portable Doppler radar unit. It was quite successful; I can point it at cars up to about 100 feet away and hear a tone which varies with their speed. I also can get some very interesting sounds by pointing it at my PC's power supply fan or the CD drive while it plays a CD or is ejecting a CD. Below are some photos and a sound file. Right now the schematic is in paper format, I hope to scan it in soon.

Here is a WAV file (1.2 MB) of the output of the unit. In the sequence, first you hear only the background noise from the radar. Then, you hear the sound from my moving my fingers slightly in front of the antenna. You then hear the sound when the unit is aimed at my PC's power supply fan. Immediately after this, I point the unit at a fluorescent light and you hear the intense buzz which is presumably from scattering off the ions in the tube which are vibrating due to the 60Hz AC electric field. Finally, I point the unit at my PC's CD drive and you hear the motor opening the drive, closing the drive, then the drive spinning up, increasing in speed, then then dropping to zero speed before ejecting the tray again.
You can get it here: doppler1.wav.
Here is a photo of the radar unit, complete with headphones:
Here is a photo of the innards:

Model Rocketry Projects



Our model rocketry projects have included a rocket which was intended to steer towards the sun, another model rocket intended to steer towards a latex balloon and two tests of a model rocket accelerometer datalogger we designed and built (including one test that recorded 607 miles per hour (mach 0.79) and 2900 feet altitude!).

Here are a couple of links to documentation on some of these projects:
http://www.rocket-roar.com/rap/alt.html
http://www.people.cornell.edu/pages/shb7/btsam.html

Right now, I don't have time to add text about the 607 mile-per-hour model rocket test (which used an Aerotech G80 (about 16 lbs thrust) on a 1/2 lb rocket!), but here are the acceleration, velocity, and altitude graphs from that test:




You can see a movie of this launch here: Launch1.mpg(7.5 MB)

Additional Projects

I hope to add more to this page, but for now, here are links to my personal page and also to my tutorial on basic wireless communication for microcontrollers (BWCM), which is, unfortunately, still not finished.
http://www.people.cornell.edu/pages/shb7
http://www.rocket-roar.com/BWCM

Email Sean(shb7@cornell.edu)

Sean's Personal Home Page

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