I know, I know, you’re tired of my waffling on about my Geiger counter by now, but it keeps on popping up in my mind for all sorts of reasons, such as this very cool oscilloscope for iPads, iPhones, and iPod Touch devices.
Quite apart from anything else, the fact that the local Browns Ferry Nuclear Power Plant was badly hit by last week’s tornadoes makes me wish I had my Geiger counter to hand. Not that there was any radiation leak you understand – it was just the main power feeds coming out of the plant that were disabled – but still…
The good news is that a few days ago I received an email from electronics hero David Ashton in Australia saying that my non-counting Geiger counter had finally arrived. So I’m now aquiver with excitement in anticipation that David will get the little rascal working and send it back to me so that I can play with my radioactive balls (take that smirk off your face – what did you think I was talking about?).
One thing that would have been very useful with regard to debugging my Geiger counter would have been an oscilloscope. Sad to relate, I don’t currently own one … I just never got around to replacing my old one when it died.
On the other hand, I currently have a really clever little device called the iMSO-104 from Oscium (www.oscium.com) sitting on my desk. In the past I’ve seen a number of FPGA-based oscilloscopes that plug into the USB port on a PC, but I’ve never seen anything similar for the iPad or its cousins, until now…
The thing is that the iPad provides a great platform for displaying all sorts of stuff. For example, consider the following video of an oscilloscope application for the iPad that uses its internal microphone to pick up sound and displays the corresponding waveforms. This would keep kids (and me) amused for hours.
Of course the above demo is purely software based (apart from using the iPad’s microphone). By comparison, what the guys and gals at Oscium have done is to create a connector-based adapter containing a Cypress PSoC 3 chip. This chip is used to process incoming analog and digital signals and manage the two-way communication between the adapter and the oscilloscope software running on the iPad.
In this image, the iMSO-104 is the small connector/adapter plugged into the right-hand side of a standard iPad. The software is free to download from the Apple Store (it runs in demo mode without hardware attached). The really cool thing is that the iMSO-104 and its software are compatible with all hardware iterations of the iPad, iPhone, and iPod touch. The following video shows me unpacking the box and connecting the iMSO-104 to a friend's iPod Touch:
The iMSO-104 simultaneously supports four digital channels up to 5MHz and one analog channel up to 12 mega-samples per second. On the one hand these aren’t tremendously high performance values – on the other hand they would work well for many of my projects.
I really like the fact that – in addition to the iPad – the iMSO-104 also works with an iPhone and an iPod Touch (I’d like it even better if I had an iPad or iPod Touch myself [grin]). The thing is that a lot of folks already have one of these products, so the ability to turn them into an oscilloscope is really rather cool.
One of the really nice things about this is the intuitive usage model, which takes full advantage of iPad-iPod-iPhone touch screens. Setting the analog trigger level, for example, is as easy as touching the right side of the screen and swiping your finger up or down. Changing the vertical and horizontal scales can be achieved by moving two fingers away from each other. And you can rearrange things by touching and swiping the desired channel to any position on the screen to customize your display.
Of course cost is also a factor. At $297.99, the iMSO-104 isn’t particularly cheap (although the iMSO-104 is now available for pre-order, it won’t start shipping until 20 May 2011). Having said this, it’s in line with FPGA/USB equivalents for PCs. Of course it’s true that the FPGA/USB equivalents I’ve seen for PCs can typically handle higher bandwidths and trigger rates. But the other side of the coin is that you also have to lug a PC around with you. By comparison, it’s much easier to stroll around with an iPhone or iPod Touch plus the iMSO-104 in your pocket.
Yet another consideration is that you can get a fairly respectable 50 MHz lunchbox-sized scope for around $400 these days. Of course, such a unit will typically have a screen only a few inches in size. This is one way in which the manufacturers of professional scopes make their money – you can typically add anywhere from $500 to $800 per inch of display (of course the other specifications go up as well). By comparison, if you use the iMSO-104 in conjunction with an iPad, you have a beautiful 9.7” diagonal display for a relatively low cost (assuming you already own the iPad).
At the end of the day, this is something that some people will love to bits, while others will remain relatively uninterested. For myself, I think that this is really rather tasty and I wish I’d thought of it first (grin).
HM, thank you for the suggestions. We're always looking at ways to improve on what we've done. Regarding power consumption:
If you're using an iPhone / iPod touch, you can use iMSO-104 continuously for approximately five hours.
If you're using an iPad, you can use iMSO-104 continuously for approximately eight hours.
I may like to suggest following: Since it is designed for iPAD and iPhones, why not put wi-fi into small oscilloscope module and make it wireless oscilloscope? This way it will be very convinient to use and one may use this device with mnay more platforms.
How about power. It drains power from iPhone. How long one can use in this mode? Is there provision to connect power for long usage?
Here's another pocketable oscilloscope, a bit different in concept but a great technology tour-de-force: http://www.seeedstudio.com/depot/preorder-dso-quad-p-736.html
They made a (IIRC) 500-unit production run, and they're going fast, if you want one.