Inspiration & What is does

With Canada's aging population, it is important for medical and engineering industries to recognize the increased demand for support in health and technology, especially with medical issues with known correlations to age such as stroke. 9 out of 10 stroke survivors experience some degree of paralysis in their limbs. This proportion of people go onto lead severely altered lifestyles as they learn to adapt to living without a former limb. Our device proposes to change that and allow folk experiencing paralysis in a limb to continue to use said limb in day-to-day life via an exoskeleton controlled by a Myo armband that will detect muscle activity in a different region of the body and allow that information to be translated over to the paralyzed region in question.

How we built it

  • Step One: designed the physical prosthetic components onto Solidworks 2017
  • Step Two: printed and assembled the components
  • Step Three: downloaded necessary SDKs for Myo armband
  • Step Four: calibrated and got acquainted with the armband to understand functionality
  • Step Five: wrote Arduino code that implemented each component into one system
  • Step Six: designed circuit and wired circuit components
  • Step Seven: compiled and uploaded code to Arduino
  • Step Eight: connected all components and began troubleshooting

Challenges we ran into

It is unsurprising that a software themed hackathon would have little support for mechatronics related projects. However when my team of Biomedical Engineering students and myself (a former Biomechanical Engineer, present Systems Engineer), realized MLH offered the choice of renting out hardware, the prospect of representing the University of Guelph's experience and focus on biomedical instrumentation, namely with respect with smart prosthetics, was too excitable to ignore.

However, the decision to veer off route resulted in quite a few speed bumps along the way, listed below:

  • We didn't have access to basic equipment such as callipers and breadboards, for the 3D modelling and circuitry portions of the project. We asked all around, and a WiSE exec happened to have a caliper on him (thank you, Nick!), as for breadboards, we were simply extra cautious and pedantic with wire colour coding to avoid destroying any borrowed elements.

  • We also lacked access to a motor driver IC for the motor-arduino interface. This was our fatal mistake as we weren't able to run both signal and power to the motor. As a result, we weren't able to link Myo armband inputs to motor outputs. (In layman's terms, due to how the Arduino is set up, without a driver we were only able to either power the motor (provide blind voltage; without signal/direction) or provide a signal but without voltage (the motor knows what to do, but lacks the power to do it. Such as ourselves when we realized we had forgotten about this crucial step in implementing motors in microcontrollers. We attempted to isolate the power source so that we could connect the power in series to the signal (methodology explained below), but efforts proved futile without some way to simultaneously remotely access the input signal from the Myo armband.

  • Expanding on the isolated power source, we fashioned a battery pack out of spare batteries, aluminium foil, and electrical tape.

  • A minor mechanical issue that arose was that the printed parts came out a smidgen too small. Due to the early closing of the printing lab, we had to improvise parts with a disassembled pen using the spring, a cleared out inkwell, and a conveniently section ring (thank you, Home Depot).

  • We also weren't able to find any mentors or volunteers that were experienced in general mechatronics/Myo armbands/Arduinos to provide technical aid. We resorted to self teaching via Google.

Accomplishments that we're proud of

Our resourcefulness when faced with a challenge, and our sheer unwillingness to give up on the project all through the night and next morning is a proud moment that was had this weekend. Our group spent an average of 4 hours asleep throughout the whole weekend as we power-napped and Awake chocolate-d ourselves to production. As well, learning how to set up, calibrate, and use the Myo armband was a great skill/experience we're glad to have picked up. Given its many applications in various fields, it was a very inspiring component to the project.

What we learned

  • How to use a Myo armband.
  • Basic prosthetic CAD design.
  • Never, ever attempt to use a motor with a microcontroller without a driver IC!

What's next for Gesture controlled prosthetics

Our design was meant to be a scaled down proof-of-concept for larger smart prosthetic designs such as entire limbs, etc. The next logical step would be to obtain a driver chip for the motor and develop a working prototype, then scale it up to the desired sizes.

After that, applying the same technology to benefit different fields, (such as the manufacturing industry to allow an exoskeleton to aide and remove physical strain off labourers, or a rehabilitation centre for people suffering from muscular degeneration and atrophy due to a broader range of diseases and ailments, to name a few.)

A parallel step to take alongside the above would be to develop complete smart prosthetics for amputated limbs that follow the same muscle mimicry principle.

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