What do I need as my 1st oscilloscope if my current hobbies include...

[tggzzz]

The LA cares little about waveform integrity so sampling rate can be a good deal lower.  What is really necessary, and often lacking, on a LA is an external sample clock.  If there is any interest in decoding state machines, the state clock is the only one that matters.

All sane, but I would add a caveat: some LAs allow can "synthesise" an external clock. When they do that the sampling rate is halved because they are actually sampling as before and looking for transistions.

That "synthesis" can be done in two ways, depending on the LA's capabilities. Firstly by post-processing a captured trace, which is simple, cheap, requires more memory, and prevents complex real-time triggers. Secondly within the LA's hardware, which requires more capable dedicated hardware, and enables complex real-time triggers.

If you want to measure the time between closely spaced edges (say a FF setup time), a LA isn't the way to go.

That's analogue "signal integrity", and yes you do need a scope for that.

To the OP: consider that one way or another you will pay for your experience. A good strategy is to buy something cheap, find out all it can do, and when you find something it can't do you will then be in a better position to specify what you do need.

If you need to decode protocols (i.e. interpret sequences of bit/bytes as characters or instructions), then you may find a "bus pirate" is appropriate.

[Astrodev]

Can I throw in a really cheap option, try to either find someone near to you who is already experienced in electronics and has similar areas of interest, or see if there is a local hacker / builder group near you, schools and colleges are good starting places for this.

This way you can get familiar with a variety of equipment and learn how to use them before actually spending any money on something that may not do what you need, or is frustrating because you can't get the results you need due to problems in the setup of the test system and not knowing why it is not doing what you expect.

[Peabody]

OP, it looks like you're in Atlanta.  I suggest you go to Meetup.com, and look for groups in the area related to electronics, robotics, makerspaces, etc., and attend a meeting or two.  There should be a number of people who could give you some advice, or even let you come over and use their scope.  Or, maybe you could find someone at Georgia Tech.

I'm a hobbyist too, and recently faced the same decision.  I ended up getting the DSO150 Shell scope kit from Banggood for $22.  Of course it's limited in what it can do, but so far it's been good enough for what I need.  I can't look at a processor's 16 MHz clock signal with it, or anything related to RF.  But for servos, steppers, PWM, and even transmission protocols if they aren't too fast, it works fine.  It's only one channel, which so far has been enough, but probably won't be forever.

Today I'm working on building an I/R remote controller for my Sharp TV to do some things automatically with volume, power off, etc.  I looked at Dave's video on detecting what the existing remote is sending, and getting an Arduino to do the same.  It's number 506.  The fastest thing I would need to deal with in that process is the 38 KHz carrier, and my scope does ok with that.  But the digital transmission that modulates the carrier takes place much more slowly, and any scope can handle that.  So basically, I was able to get to the same place with my dinky little kit as Dave did with his 40 GHz scope, except that I can't zoom.  Ok, exaggerating about the 40 GHz.

So as others have said, it's all about what you need the scope for, and what you'll be doing with it.  I went for years without having one, and went for the lowest cost option just to see if it would be at all useful.  It absolutely has been.  I'd guess I'll be buying a "real" scope in the future, but I don't think this one will ever stop being useful.  I even modded it to be battery powered.

There's also the Hantek 6022 mentioned elsewhere.  It's a USB scope that requires a computer as a display.  It would be substantially more capable than mine, and I think they go for about $55 now.  Two channels even.

[paulca]

I bought an OWON VDS1022I.  Working in digital circuits or audio circuits I have rarely found it's bandwidth an issue.  Except maybe trying to detect the clock on an ATMega328, but there are caveats about that anyway, since the scope will usually interfere with the clock pulse anyway.

I think the software lets it down more than the hardware, the scope display is a bit weedy on "sample" mode with no anti-aliasing or smoothing, so the trace line is very thin and there is little to no way to filter out the noise, so it's also aliased and 'wiggly'.  Doesn't look as solid as something like a Rigol, but this is more cosmetics than anything.

I successfully used it to debug an issue with WS2812B Pixel LEDs to find a slow fall time on the data square wave was causing the LEDs to fail.

For broken I2C connections I used a cheap logic analyser clone with the genuine software, yes I feel slightly guilty doing so, but I use the analyser about once every couple of months, it isn't worth the full premium price tag of the genuine article to me.  To avoid the guilt you can use Sigrok instead.  Again it's probably fine for I2C and maybe SPI connections.  You can also check the timing of GPIO pins in circuits.

As the OWON requires a laptop or PC connection and quite often I just want to quickly check something without the faff of getting the scope set up I bought one of these:
https://www.banggood.com/MINI-DSO112A-Upgrade-Version-2MHz-Touch-Screen-TFT-Digital-Mini-Handheld-Oscilloscope-With-Battery-p-977991.html

Which works suprisingly well, though the user interface can be frustrating sometimes.  It's only 2Mhz and to be honest thats a bit of a stretch.  For example it has the bandwidth to show you the data trace to NeoPixels, but not enough resolution to detect if the problem is in the signal or the scope.  Mostly the later.  That's at around 800Khz square wave.

[ogden]

As the OWON requires a laptop or PC connection and quite often I just want to quickly check something without the faff of getting the scope set up I bought one of these:
https://www.banggood.com/MINI-DSO112A-Upgrade-Version-2MHz-Touch-Screen-TFT-Digital-Mini-Handheld-Oscilloscope-With-Battery-p-977991.html

I would rather suggest 30$ "all in one" USB 8-channel logic analyzer + 3MHz scope:

https://www.banggood.com/LHT00SU1-Virtual-Oscilloscope-Logic-Analyzer-I2C-SPI-CAN-Uart-p-988565.html?rmmds=search&cur_warehouse=CN

it is supported by Sigrok as well.

[paulca]

As the OWON requires a laptop or PC connection and quite often I just want to quickly check something without the faff of getting the scope set up I bought one of these:
https://www.banggood.com/MINI-DSO112A-Upgrade-Version-2MHz-Touch-Screen-TFT-Digital-Mini-Handheld-Oscilloscope-With-Battery-p-977991.html

I would rather suggest 30$ "all in one" USB 8-channel logic analyzer + 3MHz scope:

https://www.banggood.com/LHT00SU1-Virtual-Oscilloscope-Logic-Analyzer-I2C-SPI-CAN-Uart-p-988565.html?rmmds=search&cur_warehouse=CN

it is supported by Sigrok as well.

But it requires a PC, has no display and only 3Mhz bandwidth.

The point of the DS0112A is that it's tiny, battery powered, with 2.5" touch screen.  It is only for those things I would sacrifice the bandwidth for quick indicative readings.

If I am going to hook up the PC for a scope I would want much more than 3Mhz, more like 20-100Mhz and at least 2 channels.

The logic analyser clones I believe are 20Mhz and cost less than lunch!

[ogden]

The point of the DS0112A is that it's tiny, battery powered, with 2.5" touch screen.

Scope for hikers? 
Ok, ok. Maybe some find value in such a toy. Not me. I would rather add 10$ and get Owon VDS1022 for 80$ or slightly more expensive VDS1022I (/w isolated USB) you have.

The logic analyser clones I believe are 20Mhz and cost less than lunch!

Yes. If you suggest that beginner shall get such clone logic analyzer disregarding his scope choice, then I completely agree. BTW please do not compare sampling rate of logic analyzer to bandwidth of the scope. It is like comparing sweetness of the apple to acidity of tomato.

Depending on money available I would suggest:

< 50$
30$ LHT00SU1 which is 24MSPS logic analyzer with bonus 3MHz BW "scope"

~100$
OWON VDS1022 or VDS1022I
+ clone 24MSPS logic analyzer (20$ or so)

>= 300$
proper standalone DSO with 50MHz BW and up
+ clone 24MSPS logic analyzer (20$ or so)

or MSO like Rigol DS1054Z

[rstofer]

If you need to decode protocols (i.e. interpret sequences of bit/bytes as characters or instructions), then you may find a "bus pirate" is appropriate.

This will work as long as the protocol is working correctly but, of course, it only says the protocol works on the Bus Pirate, not your actual project.

SPI, for example, will often have a spec relating the falling edge of CS' to the first edge of SCK.  For many uCs, CS' is controlled by code so  the timing spec for the leading edge is easy to meet.  What matters is that CS' doesn't go high until the last bit has been transmitted.  The code, in this case, has to be certain that the transmitter is empty before raising CS'.

The Bus Pirate may not show the 'framing' of the packet.  It may not be obvious from what Bus Pirate does show that, in fact, there is a framing error.  That's the reason I bought a 4 channel scope.  I want to see all 4 signals.  Decoding is a nice feature but framing is more important.

[tggzzz]

If you need to decode protocols (i.e. interpret sequences of bit/bytes as characters or instructions), then you may find a "bus pirate" is appropriate.

This will work as long as the protocol is working correctly but, of course, it only says the protocol works on the Bus Pirate, not your actual project.

SPI, for example, will often have a spec relating the falling edge of CS' to the first edge of SCK.  For many uCs, CS' is controlled by code so  the timing spec for the leading edge is easy to meet.  What matters is that CS' doesn't go high until the last bit has been transmitted.  The code, in this case, has to be certain that the transmitter is empty before raising CS'.

The Bus Pirate may not show the 'framing' of the packet.  It may not be obvious from what Bus Pirate does show that, in fact, there is a framing error.  That's the reason I bought a 4 channel scope.  I want to see all 4 signals.  Decoding is a nice feature but framing is more important.

I think we are talking at cross purposes.

You describe what can be termed the PHY layer, i.e. the voltages necessary to get bits/bytes received correctly. I was thinking more in terms of what information is contained in the bits/bytes and sequences thereof.

Both have to be correct. The former requires a scope or LA, the latter is easier with sprintf() statements or a bit of hardware that achieves the same effect, e.g. possibly a bus pirate.

[james_s]

The $100 budget is going to make a scope difficult. You should be able to find an analog scope within that range, but for working with microcontrollers that is less than ideal. You might find an older DSO like a Tek TDS340 or one of the HP units, they can be good instruments if you don't mind the bulk. For what you're doing I would agree that a logic analyzer is probably going to be of more use, however you really need to take the time to learn what these instruments do and how they can help you. Even a high end scope or LA is of no use if you don't understand how to interpret what it's showing you.

[Astrodev]

I agree that knowing how to use the instrument and being able to interpret what you are seeing is key to success, which is why I still say connect up with a local group where you can learn from others, as looking at info on the web is great these days but without the basic fundamentals it can very quickly lead you up the garden path.

Although it is not really ideal for the type of projects you want to do an analog scope is the best place to start, as a lot can be learned about how to set a scope up and methods for taking measurements.

Once you move onto software based instruments such as digital scopes or logic analysers (PC based or standalone) it can be very difficult to figure out what is wrong when things are not working as expected, this is where the groundwork in understanding the basics becomes important.

[cowasaki]

Dave has done a few videos on youtube which might help so my suggestion would be to go and have a look. 

If you had a bit more money then something like the scope I have would be ideal UNI-T 4202 which is a dual channel scope with a built in logic analyser but unfortunately your budget allows for a quite modest version of one or the other so something like that is not really an option. Based on what you are interested in I would agree with the logic analyser suggestion and go and buy one of the clones off ebay.  You could buy one of the cheap scope kits off ebay too within your budget and for an arduino that is likely to be enough.  Mess with both and you will see what you need when it comes to upgrading.