Whiskers as feedback devices

Tangent from http://discuss.biohack.me/discussion/496/low-tech-approach
Small hairlike whiskers could be attached to devices below the skin.  These whiskers could stimulate the skin from below in a small, focused region.  This has the advantage of not diffusing the movement of your device over a large surface area.  Imagine a finger magnet that has all the tactile vibration on a couple of nerve ends rather than the whole surface of the magnet.

What do people think of the idea?  What are possible materials?  Should they be transdermal or subdermal?


  • Maybe something coated with biobond? But I don't know how well that would react with subdermals.
  • @mitravelus Have you used it before?  Can it be built up to take the whisker shape?  Is it only applicable when an object is inserted?
  • It's the coating they used on the verichip so that the flesh would grow into it and prevent it from moving. I have no idea how it would react going through the skin though.
  • What do people think about Sugru, hot glue, fishing line, suture string, metal like stainless steel or titanium?  Problems with these.  Benefits.
  • Titanium is probably a bit too expensive but biosafe.
    medical stainless steel would be a good choice. Suture string ,too.
    Fishing line, sugru, hot glue... not exactly the first choice, if you can, stay away from them. While they might work, they are not made for contact with body-internals, so they might have inpurities or are contaminated. So if you can, stay away from them.

    About materials:

    Materials certified for long-term implantation are rare and expensive. You can get a lot of materials which are certified for at least short term contact. It's not perfect but at least they comply to quality an purity standard, so chances of bad side effects are a lot lower than with fishing rods and stuff.

    For more materials have a look at the wiki
    The standard handbook linked there contains a good selection of materials including polymers, glass and ceramics. Once you know what you'r looking for, you can start searching for the item with the desired quality.
  • Amazing, thank you.  I have seen titanium 20ga piercings sold at the mall and reputable online retailers.  Would I be correct in assuming that the titanium in those piercings is not suitable for long term implantation?  I had a few and they never gave me any trouble.

    Aside from the feasibility of materials, what do people think of the concept of using whiskers?
  • Nevermind the price statement. I messed up titanium and platinum prices in my head :D. In terms of compatibility, titanium is pretty much the №1 choice of all metals. It's commonly used for medical implants due to its excellent properties.
  • As a starting point, maybe only as a conversation point, would the post from a 20 gauge titanium piercing be a suitable whisker?
  • I have no experience with piercings. You may want to research about the different grades of titanium and which particular is used for the piercings in question.
  • What if we had a titanium base and a flexible outer, sort of like a fiber-optic cable?
  • That would make the most sense. metal whiskers would be awkward and if thin enough to be like whiskers, prone to bending or snapping...

  • I'm not quite sure everyone is talking about the same sort of whiskers.
    The original idea was to have a small whisker leaving an implant to mechanically stimulate a small area of tissue (instead of distributing the motion across the entire surface of the implant like with the current magnet implants).So it's not the kind of whiskers you find on many animals.
    Just wanted to bring this to attention.
  • Unless we are saying that the entire whisker is subdermal, then a small transdermal whisker that mechanically stimulates an area is exactly what a whisker on an animal is.

    Or... no.. I'm paging through this thread.. no... i'm just confused. Can someone please reclarify the design concept, please?
  • It's all subdermal. the idea is to have a whisker reaching out of an implant. So the implant can move the whisker, which in turn stimulates a small area of skin (but with a high intensity). So the actual implant does not move. This allows even big implants to have a detectable mechanical output even where nerve density is rather low. Imagine it more like a thin and short metal pin reaching out of the implant, instead of a whisker growing out all through the skin.
  • ah i see. this definitely clears this up. There was some mention of transdermal implants further up so that's where I started losing track...
  • As a side note. would there be a way to say pierce the ear but towards the base so it's against the skull and have the whisker made of some material that would downsample various soundwaves? Like if a sound wave hit the whisker at 5hz but the whisker was only capable of transmitting 3hz. Finding the right material would be difficult but it might be worth it.
  • I had thought about a string-like whisker which poked through the skin but the maintenance would be a nightmare so I abandoned it.  Plus, if it were installed in an area you shave, it might get trimmed by accident.

    From a durability standpoint a rigid whisker is the easiest to maintain.  From a human standpoint a flexible whisker is the most similar to what our bodies use.  What does everyone think about flexible and rigid whiskers?

    @Mitravelus I've thought that would be cool too.  I can see a lot of things you could do with it.  I don't know that pitch shifting is mechanically feasible especially at those low frequencies but I'm not a sound guy.  If you start a new thread with that as the topic I'll chime in there.
  • @AmmonRa: Wow, that's such a neat coincidence.
  • whisker related: http://www.jneurosci.org/content/13/10/4538.full.pdf

    Originally discussed here: http://discuss.biohack.me/discussion/342

    I wouldn't mind some danglers like a catfish has. I quit shaving because it took away too much of my drinking time, so I'm not worried about problems there. This project looks interesting.

  • What do people think we could drive these with?  Does a piezo element provide enough movement to stimulate an artificial whisker?  Are there any hair-like materials which "twitch" when electrically excited?

    @DirectorX We're trying to approach the whiskers from the other side.  Instead of a machine that reads data from sensory whiskers we want to use artificial whiskers to relay data to the body.

    Instead of having x Newtons of force distributed over the surface of a bulky vibrator imagine focusing all that force onto a single STRAND of artificial material coming out of an implant.

    Power draw could be reduced since less force is needed.

  • Depending on the shape, a piezo element may work. There are like disks and thin flat sheets which bend. The high operating voltage is a bit of a drawback, nothing that couldn't be dealt with tho. Cutting out a slice out of a piezo-disk used for piezo-based buzzers could be a good and cheap start for experimentation.
  • edited February 2014
    The Low-Tech Approach thread has a few posts by me about using whiskers as feedback devices.

    Ingrown hairs are a pain.  Would it work to use human hair as a feedback whisker?  If someone were to cut off one of their own hairs, integrate it into a project and implant it, how long would it last?  Would the body dissolve it quickly or just ignore it?
  • If you used any basic biomaterial like your own hair and implanted it, it would get broken down / ejected very very quickly.
  • image

    So if you're moving away from the idea of a titanium feedback whisker ... What about a dense, low-porosity monofilament? Teflon perhaps.
    Body piercers use it as cheap retainer jewellery, especially in experimental surface piercings. It's flexible, non-allergenic and can be autoclaved. Not 100% certain how it would stand up long-term for this purpose, though. 
    OPTION No 2: Medical-grade silicone, much like a sub-dermal 3D implant. Not as flexible as monofilament but more so than titanium. Definitely bio-compatible, however, how brittle the external component would be, I couldn't hazard a guess.
    For starters: You could look at nose screws or bones. They come in small gauges, various colours/designs and are as cheap as chips. Some even have a flat base at one end. Bioplast makes theirs from medical-grade silicone apparently.
  • Yeah, but just having a piece of plastic sticking out of your body does not a whisker make.

    I hate to use the M word, but what about using Ni2MnGa wires? Obviously, they would need to be coated, but some magnetic shape memory metal would be be much more of what you are looking for here.
    Why would you attach a sensor to a strand if you could just make the whole strand a reactive sensor?

  • @glims: 2 quick questions. 
    1. In a fantasy world, could we turn stem cells into mechanoreceptors and inject them into a targeted area to increase sensitivity?
    2. In the real world, could we turn stem cells into mechanoreceptors and inject them into a targeted area to increase sensitivity?
  • I'll give this a shot. Mechanoreceptors aren't cells, they are structures in cells. One could create a cell with mechanreceptors, and then implant that, or perhaps cause the growth of more of a type of cells through stem cell implantation + triggers.

    There are of course, the common rejection issues to contend with. Beyond that, the cells with the receptors aren't really hooked up to anything. It would be like having a multimeter, and zip tying more leads the the current leads in the hopes of increasing the precision of your readings...  You would need not just receptors but more sensory neurons as well...
  • ah, I see. I was thinking they were a type of neuron. I guess it makes sense that you can't just shoot an area up with Merkel cells then.
  • @glims I like the magnetic shape memory alloy idea. Removing the need for physical contact in the device (vs bumping a whisker when output is desired) would at the least lengthen the lifetime of the implant. Also, I'm not sure if you read the thread this one originated from but the device under consideration is an implantable, low tech (hence the mechanical workings), compass so the magnets are already there.
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