Interfacing with microcontroller pins to skin

I have a microcontroller with pins on it, that I'd like to connect to electrical signals that are carried on the surface of the skin via conductive paint. What do you guys suggest is the best way to do this? The signals are being routed from the fingertips to the forearm near the wrist. I'm considering building some electrodes using this method but the pads are too large to put five of them on the wrist close enough, and I don't think they would tolerate motion very well. Signals are active low with a pull-up resistor to 5v. Would microdermal piercings be appropriate for this? I would consider a less invasive solution superior, though. 

For more detail, I'm building a bluetooth 'keyboard' that sends keypresses when one touches their finger and thumb together, the thumb is wired to ground, the 4 fingers are connected to 4 different digital IO pins, and the microcontroller, bluetooth module, and battery are housed on an bracelet.



  • How far along are you on this project?  This sounds pretty cool!  I didn't think skinsafe conductive paint could carry enough current to really be useful beyond a few inches.
  • edited March 2013
    'skinsafe' is a matter of opinion. I'm using bare conductive paint, which isn't 'approved' for use on skin, but works just fine. It's just signals, so it doesn't have to carry much current.

    I'm at the point where I have all the components together working individually, I have yet to put them together. It's going to be a bit tight to get it all on a bracelet.
  • You might want to breadboard the microprocessor so that you can attach thin, flexible wires that you can attach to the skin paint.  This would eliminate the lead spacing problem and give you more leeway in deciding what sort of terminators to attach to the ends of the wires for attaching to the skin.  The breadboard could be incorporated into whatever apparatus (cinch strap, gauntlet, etc.) you end up using for attaching the microprocessor to the body.
  • This "Bio-patch" prototype seems somewhat relevant to this thread, and probably others will also find it interesting too.

    news release from the institute,

    you can read the first page of the paper here (if anyone has access to the whole paper, please let us read it too):
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