Free oscilloscope

[rog8811]

I mentioned this on another thread, as I had a few PM's about it I thought a new thread was in order.

I have an old single trace scope that does a lot of work for me but there are times when a dual trace is needed, I found the following free download of a very nice Scope/analyzer/frequency meter/volt meter/signal generator....and more. It all connects through your computer sound card.

http://www.hitsquad.com/smm/programs/VA/

Once downloaded and installed you will find a lot of familiar scope controls to play with, including things like a frequency meter.....

To get this up and running you will need a means of connecting between whatever you want to test and the sound card, using either the "Mic in" (which will only give you single trace) or "Line in" (dual trace).

You cannot just connect up a circuit @12v or you will kill your sound card. You need to make one of these.....

This will limit the voltage seen by the computer.
My connection cables started life as a dual male phono to mini jack plug cable.

Cut it in half(ish) and connect the jack plug lead to the attenuator circuit shown previously. I used a pair of female Phono/jack plug adaptors soldered to the board to connect the probes to.

To make the probes I just used a piece of rigid plastic tube, shrink sleeving and some croc clips for probe and earth.

I have left things in simple terms as I think if you are intrested enough in trying it out you will be able to work out the probes to a design that suits you.

As always if you have questions I will do my best to answer them, but I learnt how to do all of the above in the space of an afternoon, it is not difficult

Regards rog8811

 

[philguy]

How accurate is it?
I am thinking of frequency sweeps, where a shareware version I once tried failed to get a "good" resolution, checking intensities only at certain frequencies that had considerable space in between.


Well, I guess I will try it...can always use something like that *hehe*

 

[rog8811]

I have yet to connect it to a known frequency as I only have a sweep generator. I need to make another lead to use the inbuilt frequency generator.

I am still playing at the moment but will compare it with my bench scope when the weather gets warmer so I won't freeze in the workshop.

Regards rog8811

 

[laserrod]

Rogg,

Same here buddy, it was -13C /8F here last night.
Gonna put reflectors outside and get more help from our beautiful SUN.

 

[dataplumber9]

Thanks, rog8811

This does look like fun, and now I can scratch this off my programming to-do list. Not sure that I would have thought to use the Line-In as signal input.
Should be significantly lighter than my Tektronix O-scope.

 

[Kenom]

as far as voltage sensativity what's it's lower limits?  would it be able to see 1mv? I need somethign that's going to plot 1-1000mv over a period of time and show me a graph like for a laser power meter.

 

[rog8811]

The voltmeter goes to at least 4 decimal points, if I remember correctly, that of course doesn't mean it is accurate to that degree....I calibrated mine at 1.33 volts and it seems repeatable at that.

There is a capture facility, which I have not played with, I am not sure of the longest time that it can be set.

It only takes 5 mins to download and exe, have a play....if you don't like it uninstal is just a click away

Regards rog8811