16 July 2004

Wanderings
Number 75

Ralph J. Coppola

r_j_coppola@hotmail.com

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Feature

Many times amateur experimenters have a requirement to take measurements of one kind or another. Unfortunately, many of us can not afford a battery of exotic test and measuring instruments. Several months ago I found that my old digital volt meter (DVM) had given up the ghost. So off I went, to the local RadioShack store, to see if I could find an inexpensive replacement. Out of their selection of meters, I chose the #22-805 --- 24-Range Digital Multimeter. This meter and its upscale cousin, the #22-812 --- 46-Range Digital Multimeter, have the added feature of a serial computer interface that allows me to display and record measurements on a computer. The saved data may then be printed out or loaded into a spreadsheet or other program for post processing.

In addition to this type of meter, don't forget your computer. With the proper interface card or module, plus suitable software, your computer can be transformed into a wide variety of measuring instruments. The web offers many programs that will enable you to use your existing sound or game card for your investigations. But, if you are like me and don't want to tie up the family's computer while gathering your data, have a look at some of the local flea markets, yard sales or thrift shops. You should be able to pick up a suitable PC for under $100.

Here is a small sample of the available software:

The Electronics Lab and WebEE sites have collections of programs to enable your PC to be used to take measurements

Digital Oscilloscope uses your PC's sound card for input.

SIGVIEW is a complete real-time spectral analysis application with wide range of powerful tools and statistics functions for $99.00 US.

Spectrum FFT is a DOS audio spectrum analyzer and signal generator for $89.95 US.

The Seti League's site has a few links to some DSP and Spectral Analysis suppliers.

The Radio-Skypipe software package, from Radio-Sky Publications, turns your PC into a strip chart recorder. This application can be used with your sound card or an analog to digital converter (ADC) . Be sure to look at their Projects page.

The Redwood City Public Seismic Network has a selection of custom built analog to digital converter (ADC) interfaces. They were designed for seismic applications but should be suitable for other low frequency work.

Renato Romero's FFT for Dummies offers an introduction to using Fast Fourier Transforms (FFT) for Digital Signal Processing (DSP) of your data.

Alberto Ricci Bitti shows how to use a Casio FX9750 , FX9850 or CFX9850 pocket calculator as a graphing data logger. Here is his original CircuitCellar article.

A sensor is used to measure and record a rocket's acceleration.

DPGraph is a powerful software package for math and physics visualization. With it you can easily create photo realistic 2D, 3D, 4D, 5D, 6D, 7D and 8D graphs. $9.95 US.

Many PC users have a spreadsheet, such as Microsoft Excel, in their suite of software applications. Spreadsheets, if used correctly, can prove to be a useful tool for handling scientific data. Doing a quick GOOGLE search on <excel + scientific applications> will turn up over 200,000 hits. For starters, have a look at Using Excel for Handling, Graphing, and Analyzing Scientific Data and General Excel Links.

To take measurements you'll probably need some type of sensor. Brooke Clarke has assembled an extensive collection of links to sources of all types of sensors. Take a bit of time and wander around his site. He seems to have a bit of everything. And most of it is science or technology orientated.

HOBO has a selection of data loggers that are especially suitable for the K12 crowd.

DATAQ Instruments has a great deal! They are offering the DI-194RS, which is a 4-channel, 10-bit serial port analog to digital converter (ADC), for $29.95US. The package includes a serial cable, chart recorder software and analysis software.

B&B Electronics is another supplier of commercial computer to real world interfaces.

ePanorama.net provides some PC joystick interface circuits.

Wanderings

During these nice warm summer evenings, you may have some little furry critters flying around your back yard. Why not build a bat detector and tune into their ultrasound echo location chirps and clicks? Bertrik's bat detector page contains DIY links to several audio detectors. Also, have a look at our NJ Chapter's bat detector project for a ton of information on bats, detectors and conservation.

The American Association of Variable Star Observers (AAVSO) was founded to collect variable star observations made by amateur astronomers throughout the world. Since professional astronomers have neither the time nor the equipment that is needed to gather data on the brightness changes of thousands of variables, amateurs have been making a real and useful contribution to science by observing variable stars.

The PIXY System is a free automated astronomical image examination system developed by Seiichi Yoshida. It automatically detects all stars from an image, collates them with star data recorded in catalogues, and finds out new objects or variable stars.

Solar Observing by Peter Meadows introduces us to the safe techniques of sun spot tracking.

Ropers Knots Page may not be science related but some of these knots and hitches may prove to be useful. So get yourself a piece of rope and give it a try.

Cell Biology is a personal collection of tools for the undergrad cell bio lab by Allan Blake.

Earth Science Freeware is a collection of 27 downloadable programs.

Here are some more Java demos. This time, Brock Engineering has developed a collection of Java Animated Virtual Mechanisms.

I recently received an e-mail from Joe Huck in which he points us to The Theory of the Moiré Phenomenon by Isaac Amidror. This book may be the most comprehensive and methodical work on the theory of the moire phenomenon.

Tim Davis sends us a link to NASA's J-Track, satellite tracking utilities. This site is really interesting.

Thanks, guys!

The Kids Room

The Nevada K-12 Seismic Network is a real-time system that has been set up in Nevada science classrooms. The project fully integrates K-12 seismographs with those at the University of Nevada's regional seismic network.

MERLOT is a free collection of links to online learning materials designed primarily for faculty and students of higher education.

Midway Elementary is sharing their The Technology Loop site with teachers across the Internet.