Just purchased a PropScope

I was building some Arduino code the other day to interface with the WS2812b LED's. The code for the Propeller is pretty straight forward and thought it should be just as easy on the Arduino front.

The first problem was that I was using an STM32L board that runs at 80Mhz which is the same speed as the Propeller. None of libraries I looked at worked with that fast of a processor. The pin timing to drive these LED's is somewhat fussy.

So I setout to write some assembly code to drive the pin fast enough to drive the WS2812b when I notice that my DSO138 scope was not up to the challenge. It appears that a frequency that high is not going to work on this $20 scope. Its maximum sample rate stops at 1 Million sample per second.

I ended up writing slower code that was 100 times slower so that I could use my DSO138 to see the signal. I then upped the frequency of the code to drive the LED's. This for the most part worked. I had to do a little fixing of the code at that higher speed.

I then set my sites on a faster scope and notice that most of them stopped at the 1Mhz sample range. I was not going to spend the $1,000 price tag for a real scope which would kill my budget and not site well with my wife either.

I then took a second look at the PropScope which I thought at the time was a little pricey begin it was USB attached. I then took a closer look at the maximum sample rate which is said was up to 25Mhz. Hey, that is pretty good for a unit based on the Propeller chip. After looking at the schematic I see it was using some hardware to do the sampling and the Propeller to do the interfacing.

So I put it on my wish list as a item I wanted but thought I will site on it a while. To my surprise it went on sale and then on sale. I decided it's time to pull the trigger and see what I get.

Again I was impressed with what I got. Professional style probes and not just one but two. It also came with the PropScope DAC card which I was not expecting. The display software is quite nice as well and for looking at my WS2812b signal it was simple and easy to do. Very nice product I think.

Can't wait to figure out the other features of this product as I have other signal I need to break down.

It does look as though the software not being maintained anymore and some talk about making it open source but at this point the product works and works very well and for the price right now, its a steal.

Mike

Comments

  • 20 Comments sorted by Date Added Votes
  • PublisonPublison Posts: 9,505
    edited May 7 Vote Up0Vote Down
    Congrats on the purchase. I bought the first or second on when there were announced. Been a great scope.

    The DAC card has shipped with all scopes since the beginning.

    As far as software being Open Source in the future; not likely, since it is based on Hanno's Viewport which is still a product that Hanno sells:

    http://onerobot.org/products/viewport/
    Infernal Machine
  • The Propscope looks like a sweet device. The closed source software puts me off though.

    As for a real scope I too would balk at $1000 dollars. Can't really justify that for the tinkering I do.

    Luckily though, now a days you can get amazing scopes very cheaply.

    I got a Rigol DS1054Z. Four channels 1GSa/s, 50MHz bandwidth which can be had for 400 dollars.

    The neat thing about this is that the bandwidth can be unlocked with a firmware hack up to 100MHz. :)

    Of course what is missing is the 10 bit resolution, arbitrary waveform generator, and other features the Propscope provides.

  • Heater. wrote: »
    The Propscope looks like a sweet device. The closed source software puts me off though.

    As for a real scope I too would balk at $1000 dollars. Can't really justify that for the tinkering I do.

    Luckily though, now a days you can get amazing scopes very cheaply.

    I got a Rigol DS1054Z. Four channels 1GSa/s, 50MHz bandwidth which can be had for 400 dollars.

    The neat thing about this is that the bandwidth can be unlocked with a firmware hack up to 100MHz. :)

    Of course what is missing is the 10 bit resolution, arbitrary waveform generator, and other features the Propscope provides.
    Is the Rigol open source?

  • Of course not. It's a "real" oscilloscope. Can't expect much open source progress there anytime soon.

    Meanwhile at the low end there are open source options.

    The redpitaya is one: https://redpitaya.com/. Perhaps a bit pricey.

    There is a USB scope, somewhat like the Analog Discovery that popped up recently. With open source software. Damned if I can recall what it's called now...let me think...


  • TorTor Posts: 1,720
    Yeah, the Rigols look nice. Closed source, obviously, but the difference from the Propscope is that the Rigol is self-contained - you don't need anything else to use it. With the Propscope you need a Windows PC. So in that case it matters.

    It's also possible to come across free or cheap old scopes. I got a 400MHz Gould digital scope for free, it's very nice (and big), does basically everything I need, but it takes forever to boot. Not what I was used to from my background of good old HP and Tek analog scopes.
  • My old Tek scope took a few minutes to boot. It takes ages for all those tubes to warm up!

    I saw one the other day, next to the PDP-1 in the Computer History Museum.
  • The lights must have dimmed when you turned that on.

    I have an old Heathkit scope I built back in the day too. Only one tube in that unit.


  • Heater. wrote: »

    There is a USB scope, somewhat like the Analog Discovery that popped up recently. With open source software. Damned if I can recall what it's called now...let me think...


    http://forums.parallax.com/discussion/166486/adalm2000-a-usb-12bit-adcs-dacs-100-msps-2-channels-comming-soon-for-99#latest
    Infernal Machine
  • Bingo, that's the one.
  • Hi Mike, thanks for this post! I had also put the Propscope on the back burner a long time ago, but after reading your post, I saw what a sale it was on, and grabbed one tonight along with a 4th Activitybot. (Trying to build a collection of them so I can teach a small class at my daughter’s school or make a club there someday.)
    Anyway, for less than $100, looks like pretty nice specs for a scope. I've never used a real oscilloscope before, but I have a college level electronics course I'm slowly working through that uses them a bit, so I’m looking forward to it now. Thanks for alerting us to the sale once again. :)
  • I see that the PropScope price ends in the magic ".87". Does that mean it's being discontinued?
  • David Betz wrote: »
    I see that the PropScope price ends in the magic ".87". Does that mean it's being discontinued?

    Looks that way. The hourglass symbol (limited lifetime product) is also shown at the product page.


    Get 'em why you can!

  • I think the price just dropped again to $69.87:

    https://www.parallax.com/product/32220

    How can you resist? I paid $249.00 when they first came out.
    Infernal Machine
  • Publison wrote: »
    I think the price just dropped again to $69.87:

    https://www.parallax.com/product/32220

    How can you resist? I paid $249.00 when they first came out.
    And now it does say "FINAL SALE". It's a great price but I already have a Saleae Logic 8. Can the PropScope do anything that the Saleae can't? To be honest, I've never actually tried getting the Saleae to display analog signals although it claims to be able to.
  • David,

    I guess you have a newer Saleae. The Saleae are good because the software is always upgrading. The PropScope software has been fixed for years.

    That being said, I like Hanno's software that comes with the PropScope. Got some neat features from ViewPort.

    I will try and do a comparison in a few days.
    Infernal Machine
  • Publison wrote: »
    David,

    I guess you have a newer Saleae. The Saleae are good because the software is always upgrading. The PropScope software has been fixed for years.

    That being said, I like Hanno's software that comes with the PropScope. Got some neat features from ViewPort.

    I will try and do a comparison in a few days.
    Yes, I have one of the newer Saleae units. I'll look forward to your comparison. I imagine that the PropScope might be better for analog o-scope things than the Saleae. It seems to be primarily designed as a logic analyzer.

    Has anyone come up with alternate firmware for the PropScope? I guess the standard firmware is not open source?
  • David Betz wrote: »
    I guess the standard firmware is not open source?

    I wish!

    Anyone is close to Hanno?

    The scope is a great bit of hardware, and allowing the community to continue software development would be a true legacy.


  • TorTor Posts: 1,720
    Some of us tried, some years ago. There's an old thread about it over on Propellerpowered. But we didn't come far. Kuroneko got deeper into it than the rest of us, with some code that could engage a bit of the 'scope.
  • Glad I bought one at the $70 price, they're now $100.

    (For those of you who desire additional accuracy, they're $99.87).

    Nice unit, works well even with my 10-year-old laptop.

    Has anyone written a protocol analyzer like Saleae (for decoding I2C, etc.) for this unit?
    Tulsa, OK

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  • PublisonPublison Posts: 9,505
    edited July 12 Vote Up0Vote Down
    wmosscrop wrote: »
    Glad I bought one at the $70 price, they're now $100.

    (For those of you who desire additional accuracy, they're $99.87).

    Nice unit, works well even with my 10-year-old laptop.

    Has anyone written a protocol analyzer like Saleae (for decoding I2C, etc.) for this unit?
    No. We asked Hanno to write one, but the money was not there in the budget to do it.

    And another earthquake in New Zealand.

    https://www.stuff.co.nz/national/94633238/earthquake-strikes-new-zealand



    Infernal Machine
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