EEVblog #359 – QDSO Pocket Oscilloscope ReviewPosted on September 25th, 2012 11 comments
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Dave reviews and tears down the QDSO (“MiniDSO”) Pocket Oscilloscope.
UPDATE: Since this and Mike’s review, DIYertool have voluntarily removed this product from sale.
Great review, even if the piece is garbage.
I did want to point out that the V-/V+ may conveniently match to “Volts” but I would guess it is still re-used from “Volume”.
Such a shame that at least a bit of pride wasn’t put into making this at least a tad useful.
Cheers, again, for all your videos.
Someone should redesign this because the specs are there. If you ware to fix the crapy analong front end, rewrote the software from scratch and silkscreen the damn case properly this thhing could have been an awsome little instrument.
As alaways it will never come close to a real bench scope but it could have been useful for a lot of quick scope tasks if all the kinks ware worked out.
I wonder how it came to exist. Did they get down at a product meeting and see there were a bunch of MP3 player cases lying around as surplus and tried to build an oscilloscope around it? Or that they had an oscilloscope design and needed a case, and was dumped this huge lot of excess MP3 player cases to which they adapted their design to fit into?
Or did they somehow just take the guts of an MP3 player, removed the audio output part and replaced it with the connector and change the DAC to an ADC?
Just how this product came into existence would probably be pretty fascinating all by itself.
And that Analog Devices ADC was probably a fake. The ink stamp looks WAY too blurry for it to be an authentic part (and I think ADI was converting over to laser etched markings rather than inked ones).
The other fail was the way it was packaged. The unboxing said it all – just a bunch of crap tossed in the box – no foam or cardboard frame to hold the product secure and keep it from rattling around loose inside.
And what’s with the signal waveform? Jiggly lines. The screen is 320×240, and there would probably be about 230 or so lines on the display, so the ADC’s range would cover less than a pixel on the display. The fact that it jiggled 2-4 pixels meant it was out by at least 2 bits! So you had an oscilloscope that generated 2 bits of noise added to your signal. Fun!
Btw. the Dso Nano is worse.
I would immediately trade my Nano against one of that QDSO pocket scopes,…
If only the Chinese (or someone) would do one of these properly. There’s a lot of money to be made at the $100 (or so) price point for a 40-60 MHz pocket DSO if they just pay attention to the details.
@Rubi said, “I would immediately trade my Nano against one of that QDSO pocket scopes,…”
That’s a review of the Nano in one sentence!
The little DSO Quad seems a completely different beast.
Still a toy compared to serious bench instruments, but much better quality wise from this pile of crap.
Google “mp5 wholesale tft multi player” and you will find the device that spawned this. I believe it is a media player with changed firmware and using the sound recording ADC.
Somebody should buy the MP5 Wholesale TFT Multi Player from Storego or some other China supplier, the one that looks exactly the same…
… And then tear it apart and compare it to this device!!!
I wonder if it is just customized firmware, programmed differently on the FPGA or if there are actually different chips.
I wonder if the “bodging” of the circuit it because this device had a different use?
tl431 is a voltage reference which is driving the opto for feedback across the isolation barrier. Classic design in isolated DC/DC.
Small correction for review. I have seen there a probe compensation, on mainboard near the probe slot!!!
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