Step 2 - Planning the build
Planning the build: To start you will need various components and equipment. Some of this is optional!
NOTE: For your first version I would stick to keeping it simple. Get all the non-optional components and then build the version that uses the Potentiometer (you will see this option when you get to step 5). After that, I would experiment with the Flex sensor version (you will also see this on page 5). Then once you have a hang of things you could move onto the complex machine learning version, which we are still having significant issues with :( and maybe you could help us out there!
Components and equipment you will need:
Arduino + Starter Kit, Breadboard, Wires, Potentiometer
The Arduino is a mini controller on which you can load simple software and control basic circuits. We decided to get an Arduino starter kit as we did not have any of the components, cables, and accessories. This kit came in useful as it already included the wires, breadboard, and potentiometer we needed. You may also choose to use a smaller Arduino, they come in many sizes and they should all work for this project.
Electrodes (OPTIONAL - only needed if you are going to try out the muscle sensor)
These are the electrodes we initially started using, they are 'wet' electrodes and will need to be stuck on the arm. They are difficult to get off and may cause skin irritation, especially when using them for long durations. This is why we are looking at using dry electrodes, and currently testing out some state of the art ones developed by Dr. Tong Zhu from North Carolina University.
We ended up getting a few different actuator versions from Actuonix that all worked really well. For our design, we ended up using the L12R 30mm 100:1 ratio. Dependent on the dimensions needed, and the torque requirements for your arm brace you may need to get something different to what we use.
Muscle Sensor (OPTIONAL - I would not bother with this, there are too many issues)
We started off using this muscle sensor, but could not reliably get a signal from Lorelei using this sensor. This is why we moved to use the more complex multi-sensor approach which we are still busy with. For now, this may be something you could test things out with especially if you will be using a healthy muscle/signal to be the controlling signal for your device.
7.2 volt battery or 6V 3300mAh Battery + Charger
I started testing out with 6V batteries and they worked well enough, but the actuator can handle up to 7.2 volts and works far better with higher voltage, therefore I'm now using 7.2 volt batteries for better performance. You will only need one at a time, but having two batteries allows you to use one while the other is charging.
This is the battery clip used to connect a 9V battery to the Arduino for mobile use. You don't need this when the Arduino is connected to your computer via the USB. Make sure that the Arduino you purchased includes this type of power connector, you may need a different connector if your Arduino has a different power plug.
This is the tape we use to keep my daughters' arm from pulling out of her shoulder socket. We could not find a suitable shoulder harness for my daughter's size so my wife sewed one herself but now we only use the tape.
These are screws you can use to mount the Actuator to the 3D printed braces. I'll describe the process in more detail below.
EKG-EMG Shield (OPTIONAL - I would not get this unless you want to just have some fun)
This was a fun but ultimately not a very useful component in the long term. It is a board that I used to quickly test out where we can pick up signals on my daughter's arm. It came with a few dry electrode armbands that allowed me to quickly change their position to test things out with. You will need to install some software (instructions included).
Soldering Iron, Solder Wire, Helping Hand (OPTIONAL)
We did not solder much, and you may get around not using this all together when testing, but eventually, you will need to use these when you build the final mobile unit.
TENS Unit Muscle Stimulator (OPTIONAL)
We used this muscle stimulator to stimulate my daughter's various arm and shoulder muscles. We do not know if this had any significant impact on her rehabilitation but it was good to see how over the course of several months the electro stimulation was able to move her muscle more and more.
Flex Sensor (OPTIONAL)
Currently, we are testing out a simple method or just using a flex sensor. This sensor, as it is flexed, will send a signal to the actuator and cause the arm to flex accordingly. I.E we put the flex sensor on my daughters thumb, and as she bends it, her arm comes up.
