2$ DIY Low cost USB Oscilloscope
June 10, 2011 - Posted in USB Posted by: arup
Were you going to buy a 100-1000$ valued USB oscilloscope? No need of that when you can make one at just 2$.
An Oscilloscope is a device which can analyze realtime voltage or pulse signals and plot their waveform graph in a display. It is also known as CRO, DSO or, an O-scope. It helps us in analyzing circuit output signals and pulses. Normally it is used in microcontroller projects but it’s also useful in making Any kind of Oscillator for Inverters to check what the output frequency and waveform is.

Image courtesy: usboscilloscope.info
Wondering how is this possible?
Well, this will work with soundcard. Wait, I’m not talking to use your PC’s soundcard, as if I told so, the USB term shouldn’t have been mentioned. I’m asking you to buy a USB Soundcard. Nowadays they are very cheap.
Get at eBay.com from 0.99$
Get at eBay.in from 100 Rs
Why I am asking to buy a USB soundcard and not to use the PC’s internal soundcard?
Because, if you give high voltage or spikes to the input, it may burn and if it’s a USB sound card , it will cost 1-2$, but if you burn PC’s internal Audio system, replacing the motherboard will cost you 40$.
Which software?
Well, there are many soundcard oscilloscope software, but I’d recommend you useSoundcard Oscilloscope or Zelscopeonly, because they provide good functional GUI and Soundcard Oscilloscope has signal generator too so that you can generate signals by the sound out port of USB sound card and analyze signals given to the MIC IN port of the USB soundcard.
Points to remember:
USB sound card can handle +-1V i.e, 2V p-p . If you intend to give high voltage, use voltage divider.
It can’t analyze DC signals and Ac signals<10Hz
Use shielded wire and insulated probes.

http://www.circuitsdiy.com/2-diy-low-cost-usb-oscilloscope/



Soundcard Oscilloscopedeutsche Version
Author: Christian Zeitnitz
Main features:
The PC based Soundcard Oscilloscope receives its data from the Soundcard with 44.1kHz and 16 Bit resolution. The data source can be selected in the Windows mixer (Microphone, Line-In or Wave). The frequency range depends on the sound card, but 20-20000Hz should be possible with all modern cards. The low frequency end is limited by the AC coupling of the line-in signal. Be aware, that most microphone inputs are only mono.
The oscilloscope contains in addition a signal generator for 2 channels for sine, square, triangular, sawtooth wave forms and different noise spectra in the frequency range from 0 to 20kHz. The signal can be defined by a mathematical formula as well. The signals are available at the speaker output of the sound card. These can be fed back to the oscillocope in order to generate Lissajous figures in the x-y mode.
Download the latest version: scope V1.46
Obtain a commercial license here
Interested in a customized version?
Support the development of this program by obtaining a private donation license
Additional features
Trigger modes: off, automatic, normal and single shot
Triggerlevel can be set with the mouse
The signals of the two channels can be added, subtracted and multiplied
x-y mode
Frequency analysis (Fourier spectrum)
Waterfall diagram (frequency spectrum as function of time)
Frequency filter: low-, high-, band-pass and band-stop
Cursors to measure amplitude, time and frequency in the main window
Audio Recorder to save data to a wave file
For multi soundcard system, the used card can be selected in the settings tab
The program has been written in LabView (™ by National Instruments). For the actual Sound I/O part theWaveIO package by the same author has been used. 
Signal Sources
The signals for the oscilloscope can be internal to the computer (MP3 player, function generator etc.) or from external sources (line-in, microphone). For external sources care has to be taken, not to exceed the voltage range of the inputs. The range is usually only ±0.7V !! If higher voltage need to be analyzed, a voltage divider has to be used. Additional protection diodes are recommended in order to avoid any damage to the sound card and to the computer. 
Requirements
This program will run on Windows 2000/XP/Vista/7/8 (32bit and 64bit) computers with a sound card. It will not install on older versions of Windows. The speed requirements are not very hard. A 1GHz machine is suffient. On slower CPUs the load on the system might lead to reduced responsiveness of the system.
Terms of usage and licenses
This Software and all previous versions are NO Freeware!
The use of the software and of the documentation is granted free of charge for private and non-commercial use in educational institutions
Any commercial application requires a corresponding license (see below)
Distribution and sale of the program is prohibited. Contact the author in order to obtain a resale license.
If you like to support the further development of this program please obtain a private license by following this link
Commercial usage: In order to obtain a commercial license follow this link
All right reserved.
The signal generator is utilizing muParser. Copyright ⓒ 2011 Ingo Berg
Downloads
Instructions: The program comes as a self-extracting archive and will start the installation automatically. After the installation start the scope from the entry in the program menu. Enjoy !
Version 1.46
Changes
Improved mouse control of the amplitude measurement: after the acquisition is stopped (Run/Stop) a right click into the scope window starts the measurements. A left click positions the cursor on the time axis. The left and right cursor keys allow a fine adjustment of the cursor
Mouse control of measurement in the frequency window: left click positions the cursor on the frequency axis. Fine adjustment with the left and right cursor keys
Expert mode allows to modify the sampling rate within the program and direct access to the configuration file
Solved CPU load problem for long time window
Memory problem solved
One more crash problem solved when running under Windows 2k/XP behoben
Version 1.46 of the program (all languages): scope_146
Only the englisch manual fur Version 1.46
License
All licenses obtained for previous scope versions are valid for this version as well
Private license to support the further development of the program
Commercial license for the usage in companies and non-public educational institutions
+Older versions
Final Remarks
The program requires a correctly installed and configured soundcard on your Windows computer. In case of problems consult the manual and the frequently asked question.
If you still have a software related problem send mail to C.Zeitnitz

http://www.zeitnitz.eu/scope_en


Zelscope is a Windows software that converts your PC into a dual-trace storage oscilloscope and spectrum analyzer. It uses your computer's sound card as analog-to-digital converter, presenting a real-time waveform or spectrum of the signal - which can be music, speech, or output from an electronic circuit. Zelscope features the interface of a traditional oscilloscope, with conventional gain, offset, timebase, and trigger controls. As a real-time spectrum analyzer, Zelscope can display the amplitude and phase components of the spectrum. 


http://www.zelscope.com/index.html