Toolbox

Oscium’s iMSO-104 hardware offers to turn your iPhone, iPad, or iPod Touch into a 12MSPS digital oscilloscope with an analog bandwidth of 5MHz. For folks like me with limited desk space & shifting work environments, that’s an interesting offer indeed. Oscium sent over a test model to take for a spin, so onto the spinning!

Hardware

Included tangibles are as follows:

  • iMSO-104 Mixed Signal Oscilloscope Hardware
  • 1x/10 Analog Probe
  • Logic Harness (4 Digital + 1 Ground)
  • SMD Grabbers (4 Digital + 1 Ground)
  • Screwdriver for Analog Waveform Compensation Adjustment
  • Analog tip covers (2 pieces)

The core hardware, based on the Cypress PSoC 3 chip, is housed in a slim enclosure with requisite Apple dock connector, SMB jack for the analog probe, and 5-pin male header to accommodate 4 digital channels + ground. The included set of probes appear well-built, and I estimate they’d withstand the level abuse my other test equipment is subject to. The unit also includes a small blue LED power indicator which turns off whenever the device’s related software becomes inactive.

Software

iMSO - iPhone

The iMSO’s software portion is available for free as a Universal app and includes an interactive demo mode to give you an idea of how the unit handles analog signals. The app implements standard digital scope functionality (zoom, trigger, cursor/measurement) with thankfully little UI clutter. In addition to standard menu controls, users can employ familiar pinch-to-zoom gestures as well as control voltage trigger level via onscreen sliders, and double-tap to toggle display infos.

Usage

Right off the bat, I was intrigued at the thought of using the iPad’s 9.7″ display and touch input for highly portable ‘scoping. And yes, viewing a sinewave in such a manner does feel satisfyingly slick and moreover, imbues Apple’s hardware with an air of technical sophistication rarely achieved while editing a Pages document or playing Angry Birds. The iMSO software was easily controllable via my iPhone, but I really can’t imagine using it much on that platform when given the option of a much larger display.

While it won’t replace my big ol’ 50MHz CRT benchtop dinosaur, the iMSO’s comparatively humble 5MHz analog bandwidth works well for inspecting audio signals (which I do quite often). Additionally, max voltage limits on the devices inputs (±40V analog 10x, -0.5V/+13V digital) mean I’m likely to reserve use exclusively for low-power audio work. On the digital side, the unit did prove capable when I attempted peeking in on some serial communications between an Arduino board and MCP4921 DAC chip.

The fact that iOS devices use a single port for both power & data, means you’ll have to rely on battery power while using the iMSO. Thankfully, the device + software went easy on my iPad 2′s battery – so power is likely only a concern for those who plan on marathon testing/debugging sessions.

The ~$300 pricetag and bandwidth limitations will likely limit the iMSO’s initial audience – but if those points don’t pose a problem for you, well, this thing is pretty dang sweet. As the IMSO-104 is the first in its category, It will be interesting to see what future developments hold for iOS test equipment – see, we shall.

15 Responses to Toolbox Review: iMSO-104 Oscilloscope for iPad & iPhone

  1. at that price/performance is this really anything but an excuse to get a company ipad?

  2. They had better put in some really, really good input protection and isolation, or else I would be very worried about using this with my i-device.

    • Denise Tingxi Lee on said:

      Heh, for a $300 purchase, doubt a hipster would worry about zapping the phone.

      The other comment is right, DSO quad is way better, this thing is not worthy.

    • Denise Tingxi Lee on said:

      Heh, for a $300 purchase, doubt a hipster would worry about zapping the phone.

      The other comment is right, DSO quad is way better, this thing is not worthy.

  3. Anonymous on said:

    5MHz?  while you’re at it, why don’t you give me a nice paper cut and pour lemon juice on it? (…we’re closed)

  4. Anonymous on said:

    Actually this device is fabulous on your iPhone.  Yes, the screen is small and not as convenient as an iPad, but 1> the whole setup fits in your pockets (or single shirt pocket, behind the pocket protector) and 2> is super convenient when you’re perched on a ladder debugging some sensor equipment that is (as it always is) mounted inconveniently.  I got one the week of ESC and it had paid for itself by the end of the week.

    • Fair point but considering the size of a DSO quad I can’t really see any benefits, especially when the quad outspecs this. 

      • Anonymous on said:

        I carry my phone anyway.  This thing sits in my case and I never need anything beyond 1 micro second resolution.  Ever.  It is always charged and most companies have iOS device charging stations in the forms of desk radio/media players every where.

        From a practical standpoint, this little device is simply SWEET.  Being “open” is meaningless to most professionals and has only meaning to hobbyists.  Working is what counts.  This does not replace a nice Tech DSO but in a pinch, when you are in the field, indispensable.

  5. The $200 DSO quad is 72MS/s and doesn’t require additional hardware. 

  6. While using your iPhone as a scope is pretty cool, there are some things to note:

    - 12MSPS = 5MHz only if you’re looking at a 5MHz sine. Higher frequencies will not be resolved (Shannon-Nyquist anyone?), so a 5MHz square wave will look like a sine in this scope. To get the real bandwith, you have to calculate about 10-20 samples per wave, so you end up with 600kHz to 1.2MHz. And that still only shows you something that is recognizable (i.e. you can guess it’s a square wave that goes in), but you can’t judge distortion etc.
    - single channel
    - price tag

    Bill Porter and Denise Lee pointed out that Seedstudio sells the DSO Quad, which offers 72MS/s, two analog channels, and 400V max voltage, is smaller than an iPhone, and costs 199$. I have that scope, and it allows you to recognize a square as a square up to about 3-4MHz, which is roughly consistent with the above. I think given that option, it’s hard to recommend the iPhone/iPad scope; in fact I wonder why it’s so expensive because the DSO Quad carries two probes, battery, screen etc.

  7. But you can get a DS1052E for just $100 more (ignoring the cost of iPad/iPhone) which has true 50mhz bandwidth with 1GSa/s sample rate, this thing at 12MSa/s will give you what? 1mhz usable bandwidth? And surely it’s fittable on your desk if you can fit an iPad on your desk.
    I can see no point in spending that on what is a essentially a toy.

  8. AND the seedstudio DSO sports an onboard signal generator (10-20kHz Sine/Triangle/Saw/Square)

    AND it’s open hardware! Got mine yesterday!

    The screen is flimsy, though: background has a bad (strong) angular lateral dependency (interpupillary distance is enough to produce a difference for each eye).

  9. Totally awesome.  I have an old Parallax sold unit that I need to run Parallels on my mac to use.

    Thanks!
    John

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