Hackaday Prize Entry: Antigravity Arm Floaties

A few years ago, [Mike] heard about orthotic devices for people in wheelchairs that make it easier to them to move their arms. His daughter had the opportunity to demo one of these devices, and the results with the device were good. The fights with the insurance company were not so good, but this really was a device that could be made on a 3D printer with a few rubber bands, after all. Thus, [Mike] invented 3D printed antigravity arm floaties.

The name basically tells the story — these antigravity arm floaties work well to counter the pull of gravity for individuals with low muscle tone. [Mike]’s daughter found the professional, official, not-covered-by-insurance version useful, so [Mike] decided to build his own. There’s really not much to it – it’s just a few 3D printed parts attached to a wheelchair with a few rubber bands giving the mechanical linkages some resistance.

In the true hacker spirit, [Mike] took the basic idea of these spring-loaded arm floaties and put a new twist on it. He’s using a chain as the mechanism that allows freedom of movement in the XY plane. This makes the device slightly better, and is by every account an improvement on the commercial version. That’s what you get when you can iterate quickly with a 3D printer, making this project an excellent example of what we’re looking for in the Assistive Technology portion of the Hackaday Prize.

18 thoughts on “Hackaday Prize Entry: Antigravity Arm Floaties

  1. Well done :) It id wonderful we can make things like this fairly easilly now.
    “Real” medical assistance products are obscenely priced.
    This is great. Our grandson was wheel chair bound for the last part of his life and anything that can make it a bit easier is welcome. His chair that was not even motorized was $4000 and that is quite wrong!
    Insurance companies are… Ok I won’t go there as I don’t want to pull the tone of this post down.
    What a good example of the use a 3D printer can be put to. I really enjoy mine (a Deltaprintr KS) and feel a bit lost when nothing gets printed for a few day ;)

    1. My brother-in-law makes and modifies/repairs personal wheelchairs, and it’s such a niche business that the cost is really all about making ends meet. You got one or two guys in a shop getting an order every couple weeks and the prices are pretty much just what keeps them in the black.

      Think about it this way: you can buy a generic chinese bicycle for $200 but it’s not going to be great. If you want something better you want to hire a shop to spend a week fabricating you a bicycle, and it’s going to cost you $2000 – simply because you got taxes, insurances, loans, rents, permits, certifications and fees, and paying about $1000 a week for social security, taxes, and wage for the actual emplyees who are gonna build the thing. What you’re left with is about $500 to actually build the bike, for the materials, parts and tool maintenance.

  2. In a way, I also got one of those arm floaties for work, though mine is probably just as expensive as the commercial one.
    But if you’re searching for a cheapish and pretty sturdy commercial option, take a look at steadicam vests from China. The “came”-branded ones can be had for about USD 400 including shipping for vest and arm.
    Even if you’re not interested in buying such a device, the way you can (fine-)adjust tension on those devices might be fairly easy to copy over to this design.

    Another interesting design choice might be devices like the tiltamax armor man or the came-kong.

    1. Iw2, those are some incredible references. The Tiltamax Armor looks like a perfect adult-sized solution. Something I’ve learned over the last few years is that a bunch of “special needs” and “adaptive” equipment is repurposed from some other mass-produced product or design. A lot of times there’s a solution out there, you just have to find it.

    1. But remember – if you’re unable to move without any assistance, then you’re getting no opportunity to build muscles up at all.

      A better comparison would be to all the different kinds of straps/tethers astronauts need in order to allow them to exercise.

    2. Yes and no.

      I can’t speak of this particular case but there various conditions where applying pressure is just not possible for various physiological reasons.

      I used to repair electric chairs and had one young las who was unable to exert any force for an extended period of time even pressing a joystick was too much. I used capacitive proximity sensors to activate the chair.

    3. It seems to me that she can’t move her arms at all since they’re too week to move against gravity, but remove gravity via the “floaties” and the muscles can move, and hence exercise, which will improve their strength. I think this could be best be seen as similar to exercising in water, the bouncy lets weak muscles exercise when they otherwise couldn’t. That also makes me wonder if this girl is given water therapy, it could be good for her.

      1. Hirudinea, you’re exactly right. This was my project and the little girl is my daughter. Over the last year and a half, the arm floats have made it much easier for her to move her arms, and as a result she’s not only been able to build up her muscles, but also she’s been able to significantly strengthen the brain connections needed to control her arms. As a result, she’s much more able to use her arms now, even when she’s not wearing the arm floats.

        Very good observation about the water, too. She loves the pool! It gives her a very similar freedom of movement. This summer she was working in it all the time!

  3. Desk lamps have the same arm design with long springs, been using that design for years.
    Unfortunately the cost of insurance in the US has increased greatly in the last few years since the .gov messed with it.

  4. Medical devices which require no interaction with blood or other bodily systems is a place where the hacker community can make a serious dent in what has become a cash cow for medical suppliers.

    My mother had mobility issues due to COPD toward the end of her life, and the restrictions medicare put on her to be able to get a scooter were idiotic. I ended up purchasing a used one and making it work better, fixing terminals, the charger system etc. until it was user friendly and trouble free.

    I see an exchange associated with a hackerspace where old or broken wheelchairs and scooters are repaired and given with little or no cost to a consumer to use. With the agreement that once it is no longer in use, it must be returned. The fees paid go to pay for materials and tooling to help with other repairs.

    if I had time, i’d champion this cause….alas I do not.

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