Planning the build: To start you will need various components and equipment. Some of this is optional and some of this will not be needed for the upgraded version we are building, but which is not yet ready. I'll, therefore, mark things as 'Optional' or 'For Upgraded Version'.

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. However, note that we will no longer be using the Arduino for future versions. Currently, we are working on our next version which will use the Raspberry Pia more powerful controller. The instructions will be updated when we are ready with the next version. You may also choose to use a smaller Arduino, they come in many sizes and they should all work for this project. 
  • 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. 
 L12-R Micro Linear Servo
  • 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)
  • 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 using 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.
 6V 2000mAh Battery or 6V 3300mAh Battery + Charger
  • These are the batteries I started testing out with and they worked well enough that I have not tested any others out. You may consider getting a 7.2-volt battery for better performance as they will also work with the actuators listed here. You will only need one at a time, but having two batteries allows you to use one while the other is charging.
 9v Battery Clip for Arduino
  • 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.
 Kenisio tape
  • 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.
 Chicago Screw (20mm)
  • These are screws you can use to mount the Actuator to the 3D printed braces. I'll describe the process in more detail below. 

  • 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 arm bands that allowed me to quickly change their position to test things out with. You will need to install some software (instructions included).
 Soldering IronSolder WireHelping 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. 

Step 1 - Understanding the problem
Step 3 - Measurements & 3D designing