Facial prothesis for holding electrodes EMG

David BoccabellaDavid Boccabella Brisbane, Australia Moderator
Hi all.
I've been working on some projects for a while, and one I have had to give up due to current technical limitations.
So I am working on stage 2 and I need some advice from the makeup guys.

EMG is a way of detecting and measuring the electrical signals that move the muscles, and this can be used to control facial animatronics i.e. - you raise your lips and your character snarls. One can use it to record movement, or to work in an ad-hoc environment like live performances where there is no script.

Ok - as you can see in the attached picture (not me) the electrodes are placeds on the skin and secured with sticky taps. The method of holding the electrodes down is not important - only that the electrodes are in contact with the skin. A semi adhesive saline gel helps there

What I am thinking of is to embed the electrodes in a silicone prosthetic so that the electrodes will always be in the correct position, and then glue the appliances on like any other makeup effect.

Several things immediately come to mind. 
1. Gluing the prosthesis with glue that is not conductive. It needs to have a firm fit and so to follow the faces underlying movement.

2. Sweating - what would one recommend to stop someone from sweating underneath the appliance.

At the moment I am just looking for feedback re the silcone appliance. The EMG side of things are all worked out.

Many thanks
Dave




Comments

  • Chris EllerbyChris Ellerby Los Angeles Admin
    For the adhesive I would use Telesis 5 silicone adhesive.  It's wonderful stuff and pretty resistant to sweating.  If you try it and find sweating has an impact on the bond (everyone's skin behaves different), there is a product called "Top Guard" that might help.

    As far as stopping someone from sweating, the best thing you can do is cool them down.  If they are in a suit (mask/helmet) ventilation with small fans can work great.

    On the subject of cooling a suit performer (something I've been researching a lot lately) there have been some recent developments in the medical world that may help.  DARPA (the Defense Advanced Research Projects Agency) recently funded a new hazmat suit design for working with Ebola patients that uses a novel cooling method.  Rather than active cooling, which typically require tethers or battery packs that quickly drain, they are using an ingenious mostly-passive system.  The air from the suit is circulated through a container of desiccants (like silica) to draw moisture out of the air.   This makes sweating extremely efficient as the dry air pulls moisture (and with it heat) away from the skin very rapidly.  I'm looking into trying something like that for one of my current projects.

    /Chris
  • David BoccabellaDavid Boccabella Brisbane, Australia Moderator
    Thanks for that Chris.
    I'll look at trying to get some Telesis 5.
    Unfortunately it's really expensive.

    With cooling - a few people are using phase-change cooling packs. They stay cook for quiet a while at about 14C. Low enough to cool bit not so low as to chill like ice.

    Being an active fursuiter it's something that is talked about a lot. Esp when we do outside walks and the games.

    http://ezcooldown.com/


  • Chris EllerbyChris Ellerby Los Angeles Admin
    Telesis 5 is pretty expensive, but it's worth it.  It's typically used pretty sparingly, so it can last you a while.

    I've seen those types of cooling vests, and they seem pretty solid.  My main concern is access to a freezer if on the road.  There is another type of cooling vest (made for motorcyclists) that circulates water over a container of ice.  One popular brand is http://www.veskimo.com/

    It may create too much bulk for some character designs, but seems to have a lot of potential.

    /Chris
  • Chris EllerbyChris Ellerby Los Angeles Admin
    Another alternative (less expensive) silicone adhesive is Skin Tite from Smooth-On.
    http://www.smooth-on.com/Silicone-Rubber-an/c2_1115_1193/index.html

    Depending on your application it may serve you just as well.

    /Chris
  • David BoccabellaDavid Boccabella Brisbane, Australia Moderator
    Hi Chris.
    Thanks for the info. I have ended up looking at Telesis 7 which is cheaper and does not need thinning.
    Skin Tite  is nice but it seem more to be for putting layers than just a glue. Over time this will cause the prosthesis to become thicker.
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