DSO nano oscilloscope

[lanternfish]

Thought this may be of interest to the group:

Basic specs:

Display 2.8″ Color TFT LCD
Display Resolution 320×240
Display Color 65K
Analog bandwidth 0 - 1MHz
Max sample rate 1Msps 12Bits
Sample memory depth 4096 Point
Horizontal sensitivity 1uS/Div～10S/Div (1-2-5 Step)
Horizontal position adjustable with indicator
Vertical sensitivity 10mV/Div～10V/Div (with ×1 probe)
0.5V/Div～10V/Div (with ×10 probe)
Vertical position adjustable with indicator
Input impedance >500KΩ
Max input voltage 80Vpp (by ×1 probe)
Coupling DC
Trig modes Auto, Norma, Single, None and Scan
Functionalities: Automatic measurement: frequency, cycle, duty, Vpp, Vram, Vavg and DC voltage
Precise vertical measurement with markers
Precise horizontal measurement with markers
Rising/falling edge trigger
Trig level adjustable with indicator
Trig sensitivity adjustable with indicator
Hold/run feature
Test signal Built-in 10Hz～1MHz (1-2-5 Step)
Waveform storage SD card
PC connection via USB as SD card reader
Upgrade by bootloader via USB
Power supply 3.7V Chargeable Lithium battery / USB
Dimension (w/o probe) 105mm X 53mm X 8mm
Pc connection: Mini USB B-Type

 

[Dippy]

Yes it got posted the other day by someone - linked to Ebay. (The Kiss of Death for quality reputation ).

Looks very pretty.
Probably fine for lightweight stuff.

I couldn't quite get my head around the 1Ms/s and Analog bandwidth of 1MHz ... ?
( I DO realise there are a number of variables but my 60MHz b/w Tek has a 1Gs/s albeit 8 bits, no doubt Martin's is bigger).

No accuracy claims in Manual.
Only DC coupling.

Driving it with Navibuttons versus proper 'scope knobs and buttons is OK for portable but for serious work will drive you nuts.

I think it's a very neat and clever little device and will probably give some nice approx value and some pretty pictures. And maybe very handy for logging with the PC connection.


But for serious , or even medium level hobby level work? Nah.

I reckon you should buy one and let us know. $89 is chicken feed after all.

 

[MartinM57]

Mine's almost the same as D's - 1Gs/s, 100MHz, 8 bit vertically.

Achieving 1Mhz bandwidth via 1Ms/s, using the conventional understanding of the terms, is impossible. Maybe there's a factor of 10 one missing either way or someone in the spec department thinks that those 2 numbers are always the same.

Not sure about the probes/connection - just shows a pair of clips (1x ?). Don't know how you would fit a 10x probe.

Single channel scopes are very limiting after the initial excitement of having a scope (some joker asks if he can make a dual channel scope by buying 2 of them)

This vs. a pro-scope is probably the same as a GBP3 multimeter vs. a Fluke 87V in many respects including the people that buy them - "I've just bought an DS nano oscilloscope - let's push the probes into the mains socket and see what it shows..."

Wouldn't mind seeing one though...

 

[hippy]

It certainly looks nice and has a reasonable price. I'd consider buying one as it would suit the level I tend to work at ... if it were not just single channel. Apart from using a scope as a meter, I've always found my work involves some other signal. There isn't even the option of a separate trigger input. IMO they missed a golden opportunity in not going dual channel and I don't understand why they didn't. If they had, I'd probably already own one.

The connection seems to be via a jack socket so I guess one needs a jack to BNC adapter to use a real scope probe.

Of course one could consider it a rather nice package with a display which doesn't have to be a scope, could be re-flashed to be a colour serial terminal. No idea how easy that is. It appears to be an ST reference design turned into a product but I could be wrong.

My bottom line : It's a nice package but it could have been so much better, more useful. Perhaps someone will produce a Mk 2 ?

 

[womai]

It's a cute design, and certainly admirable just for the idea (re-purposed mp3/media player)

Unfortunately, having only a single channel is a kiss of death for most (although admittedly not all) serious work.

1 MHz / 1M MSample/sec is the actual spec (and not typo). The internal ADC has 1 MHz analog bandwidth, but with th 1 MS/s sample rate real-time (single-shot) capturing is limited to about 150 kHz usable bandwidth max. One could of course implement an equivalent time mode for repetitive signals to make use of the full bandwidth (this is what I did on my DPScope - www.dpscope.com - which otherwise also tops out at 1 MSample/sec single-shot, albeit on two channels).

Wolfgang

 

[lanternfish]

I reckon you should buy one and let us know. $89 is chicken feed after all.

I think I will as it could be handy for those times when I am trying to locate an audio fault and no portable gear handy.

Agree that specs are low for 'serious' work. Maybe of use to those with less experience and funds who need some way of scoping picaxe circuits (as is so often suggested).

And maybe it can be hacked.

 

[womai]

Well, for exactly $89 you could also get my DPScope kit, which has two channels and 10x the usable bandwidth of the DOS nano (plus FFT mode for frequency domain work). THAT kit is certainly hackable (the command interface is public and fully documented).

Wolfgang

 

[Dippy]

Maybe he wants something that can fit in his pocket Wolfgang.

Lantern, forget about physically hacking it. You'll mess it up.
Of course, if you quickly learn C I notice it has a bootloader so with the appropriate loader you could bang in some software.
Then when you are bored with that you could reload their firmware.
Hours of fun

 

[womai]

Maybe he wants something that can fit in his pocket Wolfgang.

My DPScope doesfit in a shirt pocket. But adding the laptop would be a stretch (literally) I admit

 

[mega]

Very pretty, but for me, I'll take the DPscope, works well with the 1005pe eeePC I have, thanks Wolfgang, nice job.

Cheers

 

[lanternfish]

@Womai #7

Certainly your scope is a valuable piece of kit. I thought the DSO scope could be of interest to anyone wanting a cheapish piece of kit or for those who wanted a more portable scope (as Dippy suggests).

The venue I currently work in has a lot of very old and dodgy audio and video waylines. Sometimes we lose audio and it is a *&%# trying to locate faults. I have a pocket sized pic-based colour bar generator (from a kit) that is a godsend when sorting out good from bad video waylines. And the DSO Scope seemed like a good add-on to my kit as a previous good wayline can sometimes fail at the worst possible moment.

As for hacking the DSO scope - not something I personally would attempt but sooner or later someone will.

 

[hippy]

It appears to be an ST reference design turned into a product but I could be wrong.

Seems I was. It's a product from Seed Studio, circuit designed by their partner Mr. Cai Xiaoguang. Code appears Open Source, (C) e-Design Co., Ltd, uses IAR workbench for compilation and ST utilities to download executables into the ARM chip. It was the use of ST software which had me believing it was their reference design. Some details here ...

http://dsonano.googlecode.com/files/DSO nano firmware generation and upgrade.pdf

Probably not too hard once you've climbed the learning curve, found all the tools, source code, set things up and got everything working. But I have to admit that it was all those things which drove me towards the PICAXE and its, load source code, one-click download, environment.

 

[womai]

For simple audio applications like yours - where you often don't need to trigger on a separate clock signal (so can live with just one channel), and frequencies are low - the Nano looks like a usable solution. I'm not sure it has FFT mode, that could be helpful, too, to locate somewhat more subtle issues.

For most other applications I would highly discourage spending money on a single-channel scope, as very soon you will find yourself needing to trigger on a signal different from the one you are looking at, or wanting to compare the timing between two signals.

Wolfgang

 

[Dippy]

I think this is well beyond most people here to start fiddling with C and programming, though it does look fun.
Being conversant with making an LED flash with PICAXE doesn't mean you can leap into this...
(I just don't want to see people biting off more than they can chew).


Just simply consider it as a low-cost , low-spec scope , handy little device for odd jobs and leave it at that.
So, if it's good enough for your job then great, buy it and use it.
If not, look elsewhere as there are a million 'scope options.
Simple. What's the dilemma?

As far as 'scopes are concerned , there is a lot of scope

 

[Minifig666]

$89 is chicken feed after all.

Harvey Nichol's chicken feed perhaps?

I'd say it looks a bit 'poundlandorrific' to be awfully accurate (and reading from a low-res' screen wont help) but OK for getting an idea about what's going on.
Just wondering on a (very) tight budget for a beginner what would be the best sort of scope? CRO, PC, hand-held? And hat sort of prices should I expect?

(Sorry Dippy, for repeating what you basicly said. I need to check again before submitting posts)

 

[Dippy]

That kind of question will generate as many questions as answers.
£50 is mugger-all in the field of measuring gear.

If you want good stuff you will have to save up your pocket money. Sorry, there's no getting around that.

Do you want to tie-up a PC with a 'scope?
Do you need a portable? A good one will be expensive.
(Anyone saying "(very) tight budget" will have to realise that they'll end up with a low spec scope.)
Do you want a great heavy CRO? Or pay an extra few quid for a good digital LCD?
What is your budget really? (Please don't say £30 or I'll laugh )
Unless you get some luck with a good second-hand one then you will get what you pay for.
This will now run and run with a hundred different opinions etc. so good luck

 

[hippy]

Just wondering on a (very) tight budget for a beginner what would be the best sort of scope? CRO, PC, hand-held? And hat sort of prices should I expect?

That's going to be impossible to answer; IMO you have to come at it with the approach of what do you need and want to have, then work backwards to what you can afford. You might find there is nothing which meets both criteria, no happy compromise.

Perhaps a PC-based soundcard scope for free and then discover what you actually need.

 

[womai]

If you want good bandwidth (10 MHz or more) and can tolerate a big hunking block on your desk, try to get an old analog scope in good working condition. (forget broken ones, they are impossibly to fix without a lot of knowledge). US$50 - US$100 can get you a very decent one, BUT you need to shop around and also know what to look at. Maybe get the help of some experienced electronics guy in selection. On the other hand you can often get them for free or almost free, in that case you have nothing to lose and should just go for it.

For a more modern setup, there are now quite a few digital sampling scopes you can pick up for well under US$1000 and that delivery good performance. My personal recommendation would be the Rigol DS1052E - 50 MHz analog bandwidth (can be easily hacked to 100 MHz), 1 GSample/sec (500 kS/sec on two channels), large capture memory (1 MB) which is great to look at longer signal traces with high resolution. Rigol manufactures some of the low-end Agilent (ex-HP) scopes, and their build quality is superb - better than most other China offerings. Expect to pay around US$500 or maybe a bit less.

There is also a number of PC based scopes of very differing levels of quality, performance and usability. I personally like the Velleman line; the PCSGU250 combines a scope with a function generator (very useful!) and has sufficient bandwidth for any Picaxe work. The software is quite usable and the technical support great (the guy responsible for the software really listens to user suggestions for features and improvements). Sells for under $300.

On the lowest end I personally think my DPScope (www.dpscope.com) is the best of its class for the price (under $100). No other scope in that price range I know of is really competitive. Of course you might say I am slightly biased in this particular case

That's just a few pointers to get you started. As others have pointed out, the range to select from is huge, and it is best to first figure out what you need and then get an instrument that covers your needs even if it means spending a bit more (and/or saving up a bit longer) than you initially intended. Like anywhere, a good tools makes work so much easier!

Wolfgang

 

[Minifig666]

How about £34.41, (My monebox is bare)
A serious budget would probably be £200ish as a birtday present. When it comes to the type it is realy just what I can the most for for my money. At 14 I doubt I will need to have a scope I can take with me to trubleshoot a fault in a phone exchange! So realy a CRO would be fine (I like retro stuff too so I would asteticly prefer a CRO anyway!). The sort of thing I would be using it for would be examinig sound waves (audable) and serial transmission, that sort of stuff, nothing too complex. My main trubble is bandwidth and how high I would need. I assume with two channel scopes you can turn one off and just examine one right? (2 channel would be prefrable). I know it is tough as there is such a wide range of stuff on the market but I am just trying to work out what sort of spec I need.

 

[Minifig666]

Thanks for the plentyfull info. Sorry about my crossed post. I must say I have concidered your DPScope on many an occasion, and I know it is from someone I can trust. The only thing that worries me is my slugish PC, what sort of system requirements does your scope need? Having had a quick look at the CRO prices the price of yours us so good I think I may have to get one at £17 (P&P dammit) more and the fun of building it myself!!!

 

[womai]

One thing to add, two important advantages of any decent digital scope (including the DPScope) over legacy analog ones are single-shot capture and pre-trigger capability. The first means you can look at things that are non-repetitive, which is often very valuable for troubleshooting. The second means you can look at things that happen before the trigger even - often that is the important time span, e.g. to see what leads up to a faulty behavior. Normal analog scopes need repetitive signals to get a useful, stable waveform display, and can only show things that happen some time after the trigger. (there are some ways around that, but they are clunky and complicated, need additional hardware or specialized CRTs, and with modern scopes the reason to use them went away).

Note that quite a few of the lowest-cost PC based scopes lack pre-trigger capability. That's one of the things to look for when you are shopping around.

Also helpful is an "infinite persistence" mode where the screen isn't cleared between acquisitions - this allows the capture of rare events and glitches which would be exceedingly hard to see on an analog scope.

One more thing, it's trivial to implement a slow-speed datalogger mode on a digital scope to show slow-varying signals, and any decent digital scope has such a mode - on an analog scope you would only see a dot slowly wandering across the screen...

As for necessary analog bandwidth: audio < 25 kHz, ultrasound < 200 kHz, I2C <= 1 MHz, SPI < typically 10 MHz (most of the time < 1 MHz), infrared 38 kHz, servo motor drivers a few kHz, PWM typcally a few kHz, switch-mode power supplys < ~1 MHz, RS-232 < 115 kHz. So a ~1 MHz analog bandwidth covers most of these applications. The digital sample rate of a low-end DSO should be about 10x the analog bandwidth, i.e. >= 10 MSamples/sec in that case (higher-end scopes use more sophisticated data processing and thus can get away with only 1.5x - 3x oversampling).

Wolfgang

 

[womai]

The only thing that worries me is my slugish PC, what sort of system requirements does your scope need?

Hardware requirements for the DPScope are very low. Any PC that can run Windows XP SP3 will do. Necessary harddrive space is < 10 MB. I tested it on my 9 year old desktop and got close to 20 screen updates per seconds (which makes for perfectly fluid display) with CPU load of about 40%. In comparison my much more recent dual-core work laptop gets ~35 frames/sec at a load of around 25%, so not a huge improvement given the vast difference in processing power. Minimum required screen resolution is 800x600 pixel, so again any PC produced in the last 10 year will easily do.

Wolfgang

 

[Minifig666]

Ok thanks, my laptop is Vista and dualcore so no worries. I wonder why it runs so slow then?...

 

[Dippy]

Dunno.
Another advantage of standalone gear; you don't have to rely on the Spawn of Bill.

 

[Minifig666]

I geuss by 'the spawn of Bill' you mean PCs, yes? The only thing about stanalone gear is if it goes badly wrong it can be hard to debug. Also updating the firmware/OS can be a bit more of a pain. Apart from that I agree, stanalone is much more convinent.

 

[Dippy]

I really meant a clunky jack-of-all-trades OS.

I have 2 Tektronix scopes.
One is 12 yo and the other 10 years old - never gone wrong.
One had to go back to Tek for a safety check and they chucked in a calibration - it was away 5 days (can't imagine an anonymous Ch company giving that service ?)

No firmware upgrades. They work... that's all there is to it. Don't fix if it ain't broke.
Chuck them on the bench or the floor or balance on a shelf, press the On switch, twiddle and use.
No switching windows, so Editor can be full screen when MicroC work is being done.
Work every time. Get the job done. Bob's yer Uncle.

I realise PC stuff does have advantages, but I'll stick to my shoebox sized Tek gear.

 

[alhoop]

I'll be doggone!! My DSO201 Nano does exactly what it is designed for. Did I get a trigger pulse? It will show it and store it also. NO PC to lug around,just put it in my shirt pocket. If I want to look at critical timing then I take a scope that will allow me to do that, my 50mhz dual channel DSO. It is surprising what people want in such a small package.
Al

 

[lanternfish]

Catching up on threads. My scope arrived a while ago and has been bloody useful in locating signal faults.

Not the greatest piece of tech but portable and does the job I need it for. A couple of the other guys are looking at getting them just for their portability.

 

[Dippy]

That's good news.

Like we've being saying all along; horses for courses, if it's perfect for your application then it's perfect. Job done.

 

[hippy]

One thing to add, two important advantages of any decent digital scope (including the DPScope) over legacy analog ones are single-shot capture and pre-trigger capability.

Having played with my 'lump of lead' scope which is basically analogue with a screen-shot capture digitiser, pre-trigger is lacking and having it is an absolute godsend in many cases, especially where there's no secondary preceding signal to trigger on ( or when no separate trigger input ).

A typical, and simple, case is wanting to measure the exact length of a serial start bit of bytes sent once a second. Not easy if you don't have the exact leading edge of the start bit to work from.

Massive sample buffering can also be useful, especially if you want to capture both a long sequence and look at individual parts of it in depth.

On the positive side of even the cheapest scope there is the benefit that it may let you see something you couldn't otherwise see, confirm or deny and may instantly pay for itself in such a situation. For serial, IR and other things you may not be interested in accurate time measurements, voltages, but just want to know if what's appearing goes 100110100...