Inexpensive oscilloscope

[rimist]

I'm learning more about electronics, and have picked up a couple of e-books, both on building and repair. I have practically no funds currently, and don't see much likelihood for that to change in the near future. Therefore, I have been looking online for a free or inexpensive pc or android based oscilloscope. Does any one have any experience with these? Any recommendations for or against a particular kind?

I've come across basically three types: sound card based, lpt port based, and usb. Those are approximately in ascending cost order. Thanks for any help provided.

-Rimist

[WWNF911]

Sorry I don't have any experience with those.

I did find this though. It seems like a good deal but shipping cost I don't know or if thats completely out of any kind of price range you might be thinking of.

You are not allowed to view links. Register or Login

Here's an ebay link to some pics...
You are not allowed to view links. Register or Login

Leon

[rm357]

Sound card based will not do what you want. Even the fastest sound cards only run at 192khz limiting the fastest signal that you can look at to roughly 96KHz (look up the nyquist sampling rate for more info about sampling). DMX runs at 250kbps, pixel net at 1mbps, and most pixel strings somewhere between 400 and 1600 Kbps.

Cheap parallel port adaptors are going to have similar sampling bandwidth issues.

The more expensive adaptors will have internal memory that allows a faster sampling rate, then a transfer of a "data capture" to the computer at a slower rate.

For this type of stuff, I would not buy anything with less than a 5mhz bandwidth. For video related stuff I would not go less than 60mhz bandwidth. At work, we normally stick with the 100mhz bandwidth...

RM

[rm357]

My previous post assumes that you want the oscilloscope to support lighting type stuff.

If you just want to look at sound waves or maybe something in a 101 project kit, the sound card based solution might be ok.

RM

[rimist]

I'm looking for something I can use to fix broken consumables, GPS, cell phone, etc. I would like it to be able to be used to fix lynx equipment as well.

[charles59]

If you are mainly going to be in the digital word, a logic analyzer may be adequate (not as versatile as a scope, but normally less expensive).  For instance, a usb based logic analyzer (You are not allowed to view links. Register or Login) is $150.

But I admit, one can get a stand alone Rigol 100Mhz 2 channel scope for $400.  Both may be above your budget.

I have both, but use the logic analyzer for all my digital work.

[Rogelio]

I have an old tektronix 442 scope in my garage I was going to donate.  I believe it still works but haven't used it in years.  I seem to remember some of the selector switches might have dirty contacts so some settings gave me a little trouble.
Anyway, you can have it for shipping if you want.
Weighs about 20 pounds.
Roy

[JonB256]

I've had good luck with my relatively inexpensive DSO-2090 USB scope. Bought it on EBay over a year ago. Runs about $160 US.

Here are some screen shots when I was looking at some controller waveforms:

You are not allowed to view links. Register or Login

You are not allowed to view links. Register or Login

[rimist]

I have an old tektronix 442 scope in my garage I was going to donate.  I believe it still works but haven't used it in years.  I seem to remember some of the selector switches might have dirty contacts so some settings gave me a little trouble.
Anyway, you can have it for shipping if you want.
Weighs about 20 pounds.
Roy

Roy-
I sent you a pm
-Rimist

[rimist]

...
I have both, but use the logic analyzer for all my digital work.

Thanks for the insight. I searched for a DIY logic analyzer and came up with one particular which I will build to use on digital devices.
-Rimist