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Ask Slashdot: PC-Based Oscilloscopes On a Microbudget?
New submitter fffdddooo (3692429) writes I know it's something that people used to ask every few years, but answers get old so quickly. I'm an electronics teacher, and I'm wondering if it's possible to find some oscilloscope (and why not spectrum analyser?) for recommending to my students, to be able to work at home. I'm thinking of something near $50-$70. Two or three years ago, I'm sure the answer was No, but nowadays?
The same reader points out two options spotted on Amazon: one that's "very cheap but Khz" (it's also a kit that requires assembly), and another that aims to be capable of 20MHz, 2-channel operation. What's out there, he'd like to know, that's not junk?
http://xoscope.sourceforge.net...
Needs a or many sound card.
Have fun!
I can't call that English
We've been using the Saleae Logic 16 - https://www.saleae.com/logic16 at work.It goes from 2 channels at 100MHz up to 16 channels at 12.5MHz. We use them for debugging all the low speed stuff (serial ports, I2C, SD, etc.) - basically everything but the CPU memory interface.
Their upcoming "pro" version adds analog sampling, but it is not yet out.
This is one pocket scope for less than $100
This is another.
As long as we're talking about cheap PC-based oscilloscopes, let's talk about the other important kind of cheap PC-based test equipment, the digital logic analyzer, such as this one.
Not everybody needs one of those old HP/Agilent behemoths (you know, the ones that ran Windows 2000), and in my experience they can be a pain in the ass to use, too. (Not to mention how damn heavy and huge their are.)
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
My local Craigslist has 9 oscilloscopes listed between $50 and $150.
This one looks promising:
http://www.instructables.com/i...
An enigma, wrapped in a riddle, shrouded in bacon and cheese
Try the analog discovery from diligent(????)
Its 99$ for students, 2 channel 14 bit, 100 mhz sample speed, front end is less than this, 100 mhz 2 channel waveform generator and 16 channel digital stuff.
The buffers are 8k or less, but it seems to work okay...
Both are a bit above your price range. But the PicoScope 2200 is a nice entry level scope. Alternatively some assembly required with OpenADC.
what the fuck does the lack of a quality $50 oscilloscope have to do with "truth"?
you're right in a round-about way; "China and Walmart" got everyone used to paying almost nothing for a bunch of shiny shit, so when you actually have to pay $$ for something useful or quality it feels like an outrage for no directly-relevant reason.
"They were pure niggers." – Noam Chomsky
Take a look at http://www.digilentinc.com/Pro... $99 Student pricing
This is something I was actually in the market for at one point and had researched as thoroughly as I could a few years back. The bad news as I discovered it was that anything that's cheap is junk, and anything that's not junk is not cheap. Although this was, as I said, a few years ago now, and it's possible that other alternatives have arisen since then.
One of the best things I found at the time which was modestly inexpensive was some hardware that plugged into an iPad or iPhone. The one that I found was a device called iMSO, and it has a bandwidth in the neighborhood of a few Mhz, which isn't too shabby for an analog oscilloscope that cost under $300.
File under 'M' for 'Manic ranting'
They have ethernet and USB - amazon.com
Also, ask these questions on eevblog forums. Slashdot is not great at hardware.
small review/discussion
ie., over half of the nitwits posting so far are recommending logic analyzers. Please stop. There are also cheap JTAG programming solutions, power supplies, etc. Don't start recommending wrenches when someone asks you for a screwdriver.
*Edit - typo.... (damn, I noticed it as soon as I hit "submit") The iMSO cost *around* $300, not less...
File under 'M' for 'Manic ranting'
I have been using the Analog Discovery for an embedded systems class I recently completed. The regular price is $239 but the student edition is only $99. It’s small enough to fit in your pocket, but powerful enough to replace a stack of lab equipment. It is driven by the free WaveForms software and lets you build and test analog and digital circuits in virtually any environment, in or out of the lab. Here is the link:
http://www.digilentinc.com/Pro...
2-Channel Oscilloscope
2-Channel Waveform Generator
16-Channel Logic Analyzer
16-Channel Digital Pattern Generator
±5VDC Power Supplies
Spectrum Analyzer
Network Analyzer
Voltmeter
Digital I/O
Now supported by MATLAB / MATLAB student edition.
When recommending test equipment, I tell them the same thing that I tell those needing a PC and ask for recommendations. I ask what are your requirements, and what are your wishlist.
Start with the essentials. Do you need Microsoft Office, why? Do you need to keep in a budget? If so how much and why? Can you spend extra for extras? If you can get the extra from an alternate for less, would it meet your requirements?
The PC scope. Define your requirements. Budget is item one listed. This severly limits your options. Is above audio REQUIRED? If not some simple audio interfaces can be used. On Linux there is an oscope program that works great with a sound card. Back to requirements, are you taking absolute voltage measurements? Do you require DC coupling? If so this is not an option that meets your requirements.
If working in audio frequencies, there are some excellent free spectrum analizers for free in Linux and not sure what is the options in Windows or Mac. For Linear Frequency and Log amplitude the JAAA program in most linux repositories whorks great. For Log frequency and Log amplitude, the companion JAPA program works great. I use it to ring monitors for band/PA. Audacity does a great job creating waveforms. I use it to create frequency sweeps for sound setup with the JAPA program. The sweep generation is a little obscure. Under Generate tab, it is the Chirp function. Set start frequency, end frequency, start amplitude and end amplitude, liner or log sweep, and duration of the "Chirp" to generate your signal.
For those with a good soundcard or external audio interface the generated sound is direct digital so any noise is not in the recording, but in the analog stream after the digital. Be sure to set the project frequency high, such as 96KHZ, in Audacity to prevent ailising in the upper frequencies. This is a better signal source than any CD recorded sweep due to the higher sample frequency than 44.1K of CD.
To recap, due to budget, shop for what is free or low cost. Your interface to the outside world will be your expense. There are low cost or no cost software that can enable better capture hardware. The above while nice did not meet the stated budget requirement. Retails for $299. So is the wishlist able to justify the higher cost?
The truth shall set you free!
Be aware that you plan to use a sound card in a way it was never intended to be used. So if you hope for anything beyond 10 MHz, you are probably out of luck. And at that range, you already get "real" oscilloscopes for about 100 bucks.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
http://www.raspberrypi.org/bitscope-micro/
This seemed like something that while passed your price has oodles of potential for all kinds of teaching uses.
Look at Ebay, in some cases you may be lucky to find what you are looking for there. Don't hesitate to look at items from Agilent or Rhode&Schwartz.
Otherwise go for the reasonably priced items at sites like Conrad.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
If you are an electronics teacher, you should know better. The PC-based scopes and the various "DSO Nano" clones are universally crap and none fits into your budget anyway.
Your students would be vastly better served by buying a used analog scope, those could be obtained on eBay and similar places for a song these days. A used Tektronix or Hameg scope will beat the pants off of any PC-based toy and, more importantly, the student will actually learn and understand how the instrument works and what is being measured, because there are no "magic buttons" to push.
If the student has a bit larger budget, then the Rigol DS1052E or the newer DS1074Z is a really hard to beat value. There are also Siglents or Attens for the budget conscious, but both brands tend to suffer from poor manufacturing quality and the price is not really much lower than the Rigols.
Forget spectrum analyzer - there is no decent one for less than $1000 on the market. Digital scopes can do FFT, that helps in a pinch, otherwise the student can always record the data from something like the Rigols above and do a proper spectrum analysis on the PC, e.g. using Matlab or some other tool.
50-70$ will give your students a good if not excellent used analog scope such as suggested from numerous members in here
Other than eBay, less obvious sources for getting a scope on the cheap would be your local HAM (radio amateur) club, there is always one in your city, look them up (they're really friendly and love new faces). Another way to get some cheap scopes, is to visit the various electronics repairshops, service dept. etc. Ask nicely, perhaps bring a free pizza to the overworked technicians, and who knows? Maybe you'll end up with a Scope for the price of a decent pizza slice. (I KID YOU NOT, I've heard friends of mine who have done this, and even gotten a free Spectrum Analyzer, albeit old...but working).
Yet another source is the various tech-schools out there, they have old surplus equipment too, one of my friends also got a serious stash of scopes from them, perfectly legal. You could even look up military surplus sales, they often sell truckloads of much better stuff, some people make a killing buying pallets of Scopes, analyzers, bench multimeters, solder stations and much more from the military auctions, and re-sell them for seriously high prices on eBay.
A few things you may want to know about old scopes though, is that they are FRAGILE. Scopes around 20mhz are useful for low-end digital experiments and standard old audio & CCTV repair and experimentation (enough to teach you!) A 100 mhz scope throws you into the digital era, you don't need much more than that. When you find one (beggars can't be choosers, but if you pay a little...) then you may want to check that all the knobs are okay (yes, you can lube them yourself, but check for broken plastic bits, if it breaks - stay away), Good strong CRT (no hefty burn-ins or weak display), also look for the famous LOST TRACE (this means loose parts inside, again...stay away unless you know what you're doing).
A couple of good scope probes can be as expensive as the instrument itself, you may actually want to purchase those from China, they're okay...and cheap. Test leads are the only thing I recommend people to purchase new, because they take the most beating.
What this world is coming to - is for you and me to decide.
A number of labs like SLAC have a salvage department that collects old, but sometimes still functional equipment. If you are associated with an educational institution you might be able to get some of this stuff for free. It will be old but probably fine for some types or student experiments .
Instead of a spectrum analyzer, you can use an RTL-SDR dongle as described here. Sure it has a lot of limitations, but it only costs you 10$, and with the scanner software you can get a very wide bandwidth.
"It's too bad that stupidity isn't painful." - Anton LaVey
I know this might be out of your budget but have you looked at the MSO-19? http://linkinstruments.com/mso... I designed this as the training tool for my high school FIRST Tech Challenge team the Landroids. They used it to develop various custom Arduino & AtTiny based sensor array for their award winning robots http://youtu.be/zRwOx2D7WCw . I packed enough features in the scope so the students can tackle FPGA based projects when the need arises. It was selected by NASA as the only oscilloscope on the ISS. And the best part is that it is designed and manufactured in NJ/PA to demonstrate that affordable manufacturing can still exist in the USA.