Magnetic Strength Sensor



  • ... Maybe even use a flex PCB to mount both and bond to the face with cosmetic adhesive so it is barely noticeable if at all.

    I was thinking of something like this but with a piece of wire and a strain gage.

  • True, we don't know the particulars. If the actor doesn't move and can have a camera pointed at him/her, video-based mocap is (far) better, because more than one rigging can be captured at the same time. The iClone software offers this out of the box.

    Otherwise, they use helmets with a chin strap. Rick's idea of a strain gauge is a good one, and they're very cheap these days, even with the amp.

    For Robby and Robot B9 robots an actor just toggled a switch in time with his voice. That was to control a binary light, and this is for a servo, so it's not quite the same. Still, unless the servo is very fast it will not be able to keep up with typical mouth movements anyway. A heavy-duty galvanometer of the type used in laser light shows will accomplish the task, at 10X+ the cost!

  • idbruceidbruce Posts: 5,850
    edited 2018-07-26 - 00:38:57
    Jon, if I understand as you told it in the first couple of posts.... I would attempt a linear encoder and film. :)

    EDIT: If necessary, I would be happy to work on a prototype for measuring jaw angular movement, but I would want to be compensated a little.

    EDIT: And I would even do it in SPIN :)

    EDIT: Yep.... Linear encoder and film should do the trick

    EDIT: Just have to find center of jaw movement ( with testing and timing)

    EDIT: Slotted optical switch and a cheap transparency film......

    EDIT: Bota Boom Bota Bang

    EDIT: That's all folks !!!

    Novel Solutions - - Machinery Design • - • Product Development
    "Necessity is the mother of invention." - Author unknown.

  • frank freedmanfrank freedman Posts: 1,436
    edited 2018-07-26 - 13:30:55
    Hey Jon,
    You have not mentioned servo power or responsiveness, but I have one more thing to toss into the mix. Otherwhere or offline I may have mentioned my son's challenges, one of which was a gait study prepatory to orthopaedic surgery this last spring. The study included a series of cameras and reflective balls on him to allow analysis of his movement and floor mounted pressure plates. I would not be surprised to find that CGI relies on a variant of the same technical principles as the gait analysis process.

    Anyway one other part of the test was to monitor the firing of muscles during his movement, using wireless EMG devices. We found a muscle was firing out of sequence. They are not really that big, and were attached to the muscles in question. Since they signal to the muscles are building ahead of the actual movement, you could feed that into the mix as a component of a PID servo controller for finer controll of the servo. Gait and EMG are good for googling this stuff. If you reached out to A.T. Still, a school which specializes inPT training they would likely talk your ear off about this sort of technology if you got the right person.
    Ordnung ist das halbe Leben
    I gave up on that half long ago.........
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