Iteration 1: Explore

Started by wiring up the potentiometer and attaching an arm, this is just the pot we have planing on finding a flatter/lower profile one if this one gives us a good signal

next step was attaching it to the brace in a non destructive way as this is not the final form factor, initially tried hot glue but it did not stick to ether the Pot or the brace well, next I tried super glue which has promising results so far.

Next I needed to get the arm attached to the the lower part of the brace I just used a cut off nail through the arm and hot glued to the lower part of the brace. I latter changed this to super glue as the hot glue was wiggling too much.

Then I extended the leads on the buzzers as they came with super short leads this was much more challenging than I expected, just with how small and delicate the original connection was

then we hooked up the potentiometer to the to the Arduino nano and and had it output to the serial plotter.

I dont like how much the pot sticks out and spent some time trying to come up with alternative mounting points. It was not working out so I spent a bunch of time looking for flat potentiometers and finally came to a scroll wheel model that might work Digikey part 3352W-1-104LF

Now that we have a working circuit I soldered it up so we could attach it to the brace

Once it was all soldered up I taped it all to the brace. In that proses I broke a connection and had to re-solder it. The NPN transistor is just acting as a switch for the voltage supply to the buzzer as it requires more power than the digital pin can provide so we used the digital pin to activate the transistor

Once we had it all hooked up we wanted to untether it but still be able to see the readings so we used the Battery monitor BLE Arduino example to show us how to send a value to our phones using the BLE scanner app

Next we modified the code so it sent the value of the potentiometer instead of the garbage we initially sent, we got some garbage readings and realized that we were trying to send to big a number ( 2 bite limit of the BLE service) so we mapped the potentiometer readings to make them smaller.

We are not sure why it still says battery level as we changed the name of the service might just be the way the app it this is mostly for debugging anyway so we are not really worried about it.

Next we tested the phone charging battery and it worked grate but we have not tested how long it lasts yet!

Now that we have a working MVP, we started to zero in on proper gait and detecting limping, Elsy made this image.

The numbers in the above image are described in the book (Observational Gait Analysis by Rancho Los Amigos National Rehabilitation Center), a text that Dr. Jude pointed us to as one of the best resources for proper gait.

We started off thinking we might be able to measure the time between full extensions but quickly realized this dose not work. I think this is the crux of the problem detecting the person limping.

We did some more research and thinking about what measurements we should look for to identify a limp without a timer. Using resources from Dr. Judd (Observational Gait Analysis by Rancho Los Amigos National Rehabilitation Center), we were able to conclude that we need to try and measure the acceleration of the shin in conjunction with the potentiometer to find out when an individual is limping.

While I was investigating making the BLE work on the phone with a website I found this app called weBLE might work to send and save our data. on the iPhone as the weBLE api is not supported on Crome or safari in iOS as of yet.

On the battery front the benefits of having a battery with low voltage protection, charging circuitry, and a super stable output has been nice and we may end up keeping it. I wish we could find one with both those features with a lower profile that is not exorbitantly expensive have not found it yet but I'm still looking, the other option is to build the battery monitor circuit into the Arduino.

Link to: Mallory Benna documentation

Link to: Elsy Meis documentation