Cheap DS Nano Oscilloscope - Opinions?

I've been pondering getting one of those cheap DS Nano oscilloscopes that sell for under $100. I'm retired/disabled and on a fixed income so I don't have a lot of money. But I'm also just a tinkerer and I don't have very big requirements either.

Are any of you using one of these and what do you think of it? Is it fast enough for working with Arduinos? The sampling rate is only 1MHz, obviously you don't get much for $80. How about for some of the faster microcontrollers such as Raspberry Pi or Beaglebone? Any other complaints or praises? Should I maybe consider an inexpensive logic analyzer instead?*

*I have been using a second Arduino, running a logic analyzer sketch and the OLS logic software for some of my debugging, but I was looking for something just a little bit better.

I seldom use my analog scope any more but do use a simple logic probe and logic analyzer often here they do have an eight bit version for $149

I would strongly suggest you find a used analog 'scope before wasting money on a DSO Nano. Depending on where you live, you could probably find a pretty decent oscilloscope for $100.

This comment is about the DSO Quad, which is 72Msps (and a bandwidth that even Seeed Studio won't tell you), versus the DSO Nano, which has only 1Msps and a 200kHz bandwidth.

But that 200kHz bandwidth means that a 200kHz sine wave will appear at 70% of the actual voltage.

In addition, to display a square wave, you must also capture the odd harmonics, as a square wave consists of the fundamental frequency, plus odd harmonics (3, 5, 7, 9, etc) diminishing in amplitude with frequency. When you lose the upper harmonics, you get artifacts that aren't there like ringing on the rising and falling edges, and eventually it just looks like a sine wave. And not at the proper phasing, either. It takes roughly up to the 9th harmonic to look reasonably like a square wave, although your requirements may allow less or more.

The upshot is that with a 200kHz bandwidth, it is only going to give you a reasonably looking squarewave at about 1/10th the bandwidth. So only good up to about a 20kHz square wave.

But it is worse if it is not 50/50 duty cycle, because the shorter part of the wave requires higher frequencies than a 50% duty cycle square wave. Also, if the circuit is suffering from RFI, high frequency ringing, or even burst oscillation, it will almost certainly be at much higher frequencies.

As a long time audio technician, those are some of the reasons I would not consider a 200kHz bandwidth high enough to even troubleshoot audio equipment, much less digital processors running at 16MHz.

These little pocket scopes can be interesting toys, but I would never want one as my only oscilloscope. You may not realize that they are even smaller than the average smartphone.

For troubleshooting purposes, I consider an oscilloscope head and shoulders above a logic analyzer. The logic analyzer won't show you interference, ringing, etc. but it certainly has its uses.

polymorph:
I would strongly suggest you find a used analog 'scope before wasting money on a DSO Nano. Depending on where you live, you could probably find a pretty decent oscilloscope for $100.

Disadvantage: It will be huge and occupy half a table all by itself.

I could make a half-argument for a DSO Quad, but ... 1 megasample/sec (the Nano) really isn't enough for anything useful.

You simply won't be able to see most of the signals an Arduino can put out. They'll vanish (and you won't know if it's a bug in your program or a problem with the 'scope!)

I predict a 99% chance of regret if you buy one.

I recently bought a DSO Quad and I'm perfectly happy with it.

There is a lot of discussion about its merits and demerits in the Thread that was already linked to.

...R

Its not a bench oscilloscope, but then it doesn't claim to be. I think its great
to have in your bag as its so small and handy as a multimeter, but the limitations
are great.

Any oscilloscope is better than no oscilloscope, but think of it as opera-glasses to
a proper 'scopes mountain-top telescope!

I never use my DS nano because the timebase won't change from 20 microseconds / div to what I want, which is more like an audio setting. There might be a way of changing the firmware to do what it is meant to but I did not find that in two days.

Has anyone here fixed theirs?

For a portable, I want something that connects to my 7 inch tablet. With standard BNC connectors, not those tiny horrible MCX connectors. Or even SMA, at least they are securely connected.