Usb Oscilloscopes

[thekeyboardbum]

Hey i was wondering if anyone here had one? I am thinking about buying it but Im just afraid that it might fry the usb port . http://www.parallax.com/detail.asp?product_id=28119 [Broken] i was looking at this one but the sampling rate isn't that high =/. So its either pay 160 for all that or pay 3x amount for a better oscilloscope . I plan to be doing logic circuits and radio circuits so i am afraid that the sampling rate wouldn't suffice. So yeah any ideas? Thanks a bunch =).

 

[antoker]

Well, I'm building one right now (so i don't have to spend a lot of money). Here is a couple of tips: Before you buy a scope, try to define, what do plan to measure, what kind of bandwidth do you require, what kind of sampling speed etc.

You've mentioned that you're going to measure logic and rf-circuits, hmm, that's a broad range. Logic speed can go as high as 1Ghz and beyond, not to mention radio-circuits. If your a newbie in electronics, you should start with something low-end, something in range of 10Mhz (sampling speed) or even less, such as those usb-scopes with signal generator capabilities from National Instruments (USB-6008, for instance).

 

[thekeyboardbum]

hm that just costs as much basically. How much does it cost to make your own? Would you be willing to sell some schematics? =p
Oh by the way know any good books that talk about capacitors, inductors, electromagnetism, etc? Thanks!

 

[antoker]

Hmm, making your own scope will be like ten times cheaper than buying one, that's because most of the integrated circuits you can order as samples from different manufacturers and samples are for free. If you're a student, I'm sure that you can get your hands on some capacitors and other stuff as well. Now, I'm not selling and I will never sell any of my schematics, I usually post them on the net, for free and my scope is still in design stage. There are a lot of books that talks about caps, coils and electromagnetism. So I would suggest one of them:

- Introductory Circuit Analysis, by Boylestad

Very good book for a beginner, no fancy math. Just a straightforward description + a lot of examples.

 

[thekeyboardbum]

Hm thanks. I don't mind the math at all, infact I find it helpful if they show me the math (as long as they explain whats actually going on in the book haha).

 

[antoker]

Good, then you would like this book. ;) If you can complete the book, then you'll be able to challenge some serious problems within electronics, since this book is THE building block. After you're done and if you're able to put your knowledge to use your knowledge, then you'll become a good engineer ;)

 

[chroot]

USB oscilloscopes are basically just toys. I wouldn't even bother spending the money on them. The bandwidth of USB simply isn't high enough to make it a useful medium for this kind of work.

Are you a student or otherwise affiliated with a university? You can probably go to their labs and use an oscilloscope, or perhaps even check one out on borrow.

- Warren

 

[robojocks]

FREE SCOPE eSata or Firewire. anyone know of any?

I think the idea of building a usb oscilloscope is a fantastic idea. If you use it with a laptop it would be portable and potentially kill any benchtop scope. The problem is to find the chips that are fast enough to read the values if you want to check video or radio signals. I'm looking at eSata and firewire because the bandwidth kills usb.

Why should we build our own?
The expense of test equipment is reason why there is a lack of other things out there like better communication or data protocols or especially cheaper ones. You can't fix what you can't see. ( I talk very generally i know). Id like to create my own video protocol. :)
I know alot of young guys when i was doing engineering who where interested in radar and microwaves but the cost of the test equipment made it impossible. The other thing was to get access to the labs was a pain. It would depend on the weather or the flip of a coin even if there wasn't any classes using the lab.

The other thing is lab equipment are worse then toys. You have to a spectrum analyser and oscilloscope and then data analyser and then connect them all up one after another and waste so much time. Why can't they be put into one machine? We get what we deserve. Even the data analyser cant do what I wanted it to do.

If you build your own you could have as many inputs as you want. You can have any kind of customization you want and put all the mathematical analysis stuff right into the program and see the result right away. You can try other analysis that will ( Not might) give you better understanding of the signal. You might find other signals that the brand manufacturers wouldnt see. Then again you might not.All the tektronix and hp stuff all have the software protected so its hard to modify it to make it better even though you own the scope.


Why should we use someone elses. ( you know why)

THE FREE SCOPE.
The best results would be to create free scope like Linux. I constantly fantasize about having a scope that i could customize the program in it and put the output i want.

Anyone know of any?

Preliminary Design of the oscilloscope. ( Research)
I think the best way to build usb scope is to check out the electronic magazines at your local university library if your lucky enough to have that.

Id start by getting the right words to search with and get the free stuff off the net rather then even buy any electronic magazine because most of it taken off free websites or manufacturer websites. Its usually better too. Ive seen downloadable sample applications in National or microchip on there websites. I went to a electronics fair and they had all kinds of oscilloscope sample programs to demonstrate the chips they were selling.


There are all kinds of kits available from all over the net on how to do it and people use the usb because of it. Is there USB 3.0 yet?

Maybe a motherboard with a dual graphics card port to get the speed would work. I never have enough time.

If anyone has any ideas on usb or eSata or PCI express scopes id love to hear about it.
thanks.