Open Instrumentation Project News #7

This is Newsletter #7 of the Open Instrumentation Project.

The OIP makes open-source Tcl/Tk software and economical high- technology instrumentation hardware for students, hobbiests, engineers and scientists. The software and hardware run under Linux, Windows and Mac operating systems. Current instruments include oscilloscope (with spectrum analysis), arbitrary/function waveform generator and Bode Plot network analyser.

Details of the project, hardware and software are at

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Our contact email is:

-- NEWS --

  1. Education Resources Page, Pulse Oximeter Paper

------------------------------------------------- We have added an 'Education Resources' section to the Syscomp web site. This now has 8 project documents for a variety of design exercises ranging from very simple to advanced. The most recent addition is a 'guided design' document for a Pulse Oximeter, a non-invasive biomedical instrument for measuring blood oxygen level. We see guided design as intermediate in level between a structured design exercise and a completely open-ended design. The document provides hints and references while providing for flexibility in student designs.

  1. New Application Note

----------------------- Our application note 'Low-Cost Curve Tracer uses PC-Based Scope' is now on the web site. This paper describes how to create a curve tracer using the XY plotting facility of the DSO-101 USB oscilloscope and some simple external circuitry. An edited version is published in the February 2008 issue of Nuts and Volts magazine.

  1. Vista Supported

------------------ We have tested the instrument Tcl/Tk software under the Microsoft Vista operating system and it runs correctly. However, we had some problems with Vista itself and continue to prefer Microsoft XP. In addition, we've recently tried Ubuntu Linux and were impressed.

  1. Scope Software Update

------------------------ The DSO-101 oscilloscope software can now repeatedly dump waveform data to disk at a user-specified interval. The data is in csv format, which can be imported into a spreadsheet.

Version 1.8 of the oscilloscope software has this feature and is available on the Syscomp web site at:

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Source code is available from Sourceforge:
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  1. Arbitrary Waveform Drawing Software

-------------------------------------- The WGM-101 Waveform Generator can load and output an arbitrary waveform of

256 8-bit points. A computer program can be used to generate an arbitrary waveform that can be described by an algorithm, but other types of waveforms have been more difficult to create. John Foster has now contributed Wavemaker, a very nice Tcl/Tk program for drawing arbitrary waveforms. It's available for download at:
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We've used Wavemaker to create biological ECG, EMG and EEG waveforms, which can be seen at:

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These waveforms were created by finding an example on the web, loading it into Wavemaker as a template, and then tracing by hand.

Once an arbitrary waveform is loaded into the generator, it can be produced at any frequency, amplitude and offset within the generator range.

Peter Hiscocks March, 2008

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Great idea and really good work, thanks, Peter...

Reply to
Fred Bloggs


A basic oscilloscope can be had from for less than $100.

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It supports 100MSPS, and it's rs-232 based. You need to build it yourself, but it looks pretty simple.

Thanks, Bob Monsen

Reply to
Bob Monsen

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