EEVblog Electronics Community Forum
Products => Crowd Funded Projects => Topic started by: nathanpc on May 28, 2013, 11:58:25 pm
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Yesterday I was browsing 43oh (http://43oh.com) for the first time (because I'm considering it for a coin cell powered project) and I saw a promo for this Kickstarter campaign: XMiniLab Portable Oscilloscope (http://www.kickstarter.com/projects/920064946/xminilab-portable-oscilloscope). It rapidly caught my attention because it looked cool, so I decided to read more about it.
As far as I can see this is another one of those pocket oscilloscopes that Dave loves to rant. I would rant about this one too since the interface is horrible and you can't see much detail, at least those QuadDSO (http://www.seeedstudio.com/depot/dso-quad-4-channel-digital-storage-oscilloscope-p-736.html)s use a better input jack instead of the crappy headphone stuff and they also have a decent screen with a ok software, this XMiniLab doesn't.
As a oscilloscope it is really bad, but one of the things that really made it interesting is the fact that it also has a arbitrary waveform generator, which is something I've never seen in such a small package. I found it interesting that it had such capability and decided to share it with the community and get your opinions on it.
I'm considering backing the project just to play around with the AWG, but I would never use it as a function generator (neither as a oscilloscope) since I already have one.
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That reminds me, I have a DSO quad here for review....
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I've actually seriously considered making a product similar to this but with a 3.5" full colour TFT, two channel AWG (3MHz 5Vp-p into 50 ohms), two channel scope, 20 MHz bandwidth and 200MS/s sampling rate. In addition the slightly less useful ("wank?") features were 0-200V DC voltmeter, digital signal generation on 8 buffered outputs, and a 100mA adjustable DC power supply (shared with sig gen output.) Battery life maybe 4 hours with everything going, 8 hours scope only.
However, I eventually decided not to make it because I realised there aren't many portable applications where you need both an AWG and scope. It's nice to be able to do it, but for those applications I think they'd be better served by separate instruments. Plus, although I could probably make them and sell them at a $400 price point, I'm pretty sure China would under cut me.
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http://www.elektroda.pl/rtvforum/viewtopic.php?t=2546091&highlight= (http://www.elektroda.pl/rtvforum/viewtopic.php?t=2546091&highlight=)
Google translate http://translate.google.pl/translate?hl=en&sl=pl&u=http://www.elektroda.pl/rtvforum/topic2546091.html&prev=/search%3Fq%3DMobilny%2Bdwukana%25C5%2582owy%2Boscyloskop%2Bz%2Bwykorzystaniem%2Buk%25C5%2582adu%2BFPGA%26safe%3Doff%26client%3Dopera%26hs%3Dkkx%26channel%3Dsuggest (http://translate.google.pl/translate?hl=en&sl=pl&u=http://www.elektroda.pl/rtvforum/topic2546091.html&prev=/search%3Fq%3DMobilny%2Bdwukana%25C5%2582owy%2Boscyloskop%2Bz%2Bwykorzystaniem%2Buk%25C5%2582adu%2BFPGA%26safe%3Doff%26client%3Dopera%26hs%3Dkkx%26channel%3Dsuggest)
At least two people from elektroda (polish electronics forum) build their own mini DSOs as a BSc Thesis. I think one of them is trying to bring it to market.
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Not much of a scope spec; I have Dave's early DSO1 schematic printed-out which is probably just as good, and that was done some time ago ;-)
The kickstarter scope specs...
Oscilloscope Specifications
2 Analog Inputs
Maximum Sampling rate: 2MSPS
Analog Bandwidth: 200kHz
Resolution: 8bits
Input Impedance: 1M?, 10pF
Buffer size per channel: 256
Input Voltage Range: -14V to +20V
I'm actually working on something similar which is a re-spin on Dave's DSO1.
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www.gabotronics.com (http://www.gabotronics.com)
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As a oscilloscope it is really bad, but one of the things that really made it interesting is the fact that it also has a arbitrary waveform generator, which is something I've never seen in such a small package. I found it interesting that it had such capability and decided to share it with the community and get your opinions on it.
Search EPay for
dds arbitrary
And a number of similarly sized units will appear. Haven't tried any, so I can't talk about quality.
EDIT: Just noticed the specs on the kickstarted waveform generator: 1MSPS with a 53Khz low pass filter.
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Really too limited to have 53kHz output. IMO minimum is 1MHz for testing high frequency rejection e.g. audio amplifiers. And 1MHz is fast enough for PWM counter clock for e.g. TLC5941 (4096 clocks to one cycle = ~250Hz, so minimal flicker.) 2~3MHz is ideal. At those clocks you can run some microcontroller PLLs for testing.
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Doesn't look useful. No rotary knob for the time base and trigger offset, must be terrible to use. But then you don't need it, because the buffer is just 256 samples. So you can't use it like I need it sometimes: capture a signal, then move to an interesting position, maybe far away from the trigger point, then zoom in. And 200kHz analog bandwidth is too limited for many applications. You can't even check some clock signals of a microcontroller.
But might be good for low frequency applications, like audio, or debugging low speed UART and SPI signals. Nice that they provide the schematics:
http://www.gabotronics.com/download/xprotolab-portable/xprotolab-portable-schematics.pdf (http://www.gabotronics.com/download/xprotolab-portable/xprotolab-portable-schematics.pdf)
It's basically just an ATXMEGA32 and they are using the internal ADCs and DACs. No PGA on the input stages (and the ref input for the ADC is hard wired to 2.048V), so don't plan to measure millivolts with it.
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This is obviously a toy. It might look nice and fancy showing an audio frequency sinewave, but that's about it. This thing will never be a useful tool one could use while working on a real project.
Waste of money IMHO. ::)
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Kickstarter should add a link to projects which are discussed here, but I guess that's not gonna happen, because the more people pay, the more money for Kickstarter. At least looks like they get what is promised in the description and some Arduino-hobbyists, who don't know the good stuff, might be happy with it :-DMM
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It's a fun/interesting device with limited use in the real world, but I wouldn't go so far as to call it useless.
[Interesting footnote, Steve Wozniak of Apple fame backed the original smaller version, the XProtoLab]
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I got an Xprotolab, it's a neat toy and always brought a few ohh's and ahh's when I show it to colleges as a demonstration of what MCU's these days are capable of. The hardware is actually useful beyond the original use. You got a dev board with the ADC and DAC front end sorted out for you, plus the buttons and OLED display.
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I'm just jumping in to mention that despite the 200kHz bandwidth of the scope, the device is not just a scope.
It also has an AWG, a Protocol Sniffer (SPI, I2C, UART), and Frequency Counter.
The sniffer and frequency counter are done using the digital inputs, so they are not limited to the 200kHz bandwidth of the analog inputs.
I don't want to talk too much about my own project :blah:, but I'll be happy to answer any question.