Haptic subdermals with interchangable sensors



  • first read through i thought you meant you were making a clock out of these sensors, so you'd always know what time it was.  that could be interesting
  • I think this sounds dangerous, personally.  We're planning almost this same thing as a chestband component of the system we're working on.  I consider the upper torso best because if you look at the test video you see the subjects instinctively move centered on the area where they feel the sensation.

    But this would have to be transdermal as an implant(s) and require a power source(s) and have all kinds of associated problems, some as noted above (some not, like what about clothing?).  As a wearable it's basically easy and trouble free... sort of like armor, too.

    Not to seem like a nay-sayer or anything.

  • @E0N: We are working on inductive power solutions for subdermal implants. By "we" I mean ThomasEgi.  He is working on something really cool.
  • Have you considered these: http://ns.umich.edu/htdocs/releases/story.php?id=8386  I don't think you can buy them yet, but probably soon.  My biggest concern would probably be how much waste heat do they generate?

  • Going only by the press release, those need a fairly constant ~150 Hz. The only even-kinda constant vibration your body produces is the heartbeat. 150 BPM is not a _healthy_ heart rate, at least for any duration...

    Actually, that brings up a point: @ThomasEGI, if the Southpaw polls at a constant detectable frequency, doesn't that give the basis for an absolute time-sense? Not easily, but if you subconsciously learn that two ticks is a second, then what have you just gained?
    Possible reason to not switch off the thing completely on horizontality, just switch to polling a single electrode to maintain body-clock? I'm just thinking into a textbox here....
  • @ThomasEgi and i were talking about that a little while ago, and to skim over the technical details, the rate nerve stimulations would occur at with Southpaw wouldn't be consistent because of power saving measures.

    (specifically, an inaccurate but lower power system clock would be used for the microcontroller, and a watchdog timer would be used to keep the system asleep most of the time. the watchdog timer is not very accurate either.)

    a couple of months ago i wrote a blog post about an implantable clock project which might be of interest, though having now played with some "electrodes" (hypodermic needles with alligator clips attached) i know that there's no way a slowly incrementing current would work, and that a separate RTC chip probably isn't necessary.
  • What degree of clock skew are we talking here? (yes I could go read the datasheet, but it's much more interesting to pester you. ",)
  • 0.2 ppm . that makes about 6.3 seconds per year, a very neat clock i have to admit.
    especially interesting as it is in the single digit μA range.
  • the datasheet says "The frequency depends on supply voltage, temperature and batch variations" about the 128kHz oscillator. so, the inaccuracy is only relative to the nominal frequency, and whatever frequency the oscillator happens to be at, it'll only vary by 0.2ppm from that?

    if that's the case, then you could definitely use it for timekeeping if you measured the real frequency first, unless significant inaccuracy was caused by temperature changes.
  • was talking about the clock chip. the 128khz rc from the atmega are extremly inaccurate. good enough to time your tea or breakfast eggs but that's about it.
  • haha, ok, thought something sounded off about the 128kHz rc being more accurate than the datasheet says the calibrated 8MHz one is.
  • edited May 2012
    So I know this is an old thread, but I was really liking the idea, and untill we get away to power sub dermal implants, what do you think of using Director X's device as a haptic device, Use a belt with a sensor and have a receiver strapped to the chest, as people/things near the belt it amps up the power sent to a vibrating receiver that like that of Northpaw. The device itself would be much like bottle nose, only for objects in a certain proximity with a complete 360 degree range instead of directly in-front .
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