Summon the geek squad: An Oscilloscope Watch!
By Brian Dodson
November 16, 2013
What do you wear on your wrist, is one-third the size of a deck of cards, and helps you troubleshoot your latest electronics project? The Oscilloscope Watch, of course. The Swiss army knife of electronics, this tiny test lab (or bulky watch) includes a two-channel oscilloscope, frequency analyzer, arbitrary function generator, and a protocol sniffer. The price? An amazing US$125. Oh yes ... it also tells time.
The Oscilloscope Watch is a fully funded Kickstarter project coming from Gabriel Anzziani, the founder and CEO of Gabotronics, a niche company among those who are pushing the state of the art in test equipment to smaller and less expensive units. He has been engineering test units with essentially the same capability as the Oscilloscope Watch for many years, continually seeking to shrink size and price without shrinking performance.
So let's get to the specs and pics. While bulky, the Oscilloscope Watch is about the size of a number of sports watches – although I do suspect that the person chosen to model the watch in the lead photo must have a rather large wrist. The watch measures 2 x 1.6 x 0.6 in (5 x 4 x 1.5 cm), and weighs in at a massive 1 3/4 oz (50 g). The battery is a 3.7 V 400 mA lithium-ion cell, which can power the oscilloscope and related features for a solid 12 hours. The device will function as a watch alone for about 30 days, as the analog circuitry is shut down when in watch mode. Charging is done through a micro USB port.
The Oscilloscope Watch has a 1.28 in (3.25 cm) Sharp Memory LCD display packing 128 x 128 pixels. The display includes one bit of memory for each pixel that remembers that state of that pixel, and holds it in that state until changed by a specific command. The result is that the watch only has to supply enough power to change pixels in an image, rather than having to redraw the entire image on every refresh cycle, saving an enormous amount of power compared to a conventional active display.
The Oscilloscope Watch is built around an ATxmega256A3U microprocessor. This is a standard 8-bit embedded microprocessor that runs at 32 MHz, has an integrated USB transceiver, and 256 Kb of flash memory. The ATxmega256A3U comes equipped with 16-channels of analog to digital conversion, with 12-bit resolution and a sampling rate of 2 MHz. It also has two 12-bit digital to analog output channels. These analog interfaces form the foundation for most of the Oscilloscope Watch's features.
The other components include operational amplifiers, display circuitry, electronic analog switches, and various non-CPU logic chips. (For more details, a copy of the OW's schematic appears in the Image Gallery.) Somehow all this, along with passive components that make a grain of rice seem huge, and a considerable number of jacks and connectors fit on the circuit board shown above.
Once assembled, the Oscilloscope Watch looks like the figure above, (at least, if you have x-ray vision). The packaging appears clean and efficient, but I'm glad I don't have to troubleshoot this thing!
How about performance? Realistically, even though the Oscilloscope Watch can do just about anything you might want of such a device, it is pretty slow at everything it does. It is far more capable than units designed to use the audio chip of a PC to hook up to analog signals, but any electronic event that takes place in fractions of a microsecond will remain beyond the grasp of the device.
Once that is accepted, however, you are left with a remarkably capable electronics diagnostic unit that you can use at the top of that 60-ft tower, and which will tell you when its quitting time. I'm hoping someone comes up with a real-time interface to an EEG headband, so I can monitor brain waves while doing various daily tasks. The video below gives a lot more info. Not bad for the price – I'm getting one.
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