Seventeenth Week:
Applications and Implications


As was schedule in this assignment I will answer some question about my final project






What will it do?


I'm going to design, process, produce and program a leg exoskeleton which can be used in medical treatment. It could be controlled with a switcher with 4 buttons and an emergency button which will stop the machine in dangerous situations. It can be controlled using a bluetooth module with an designed App for Android systems. To move you leg and hold your full body I use 2 Electrical Linear Actuators connect to a Voltage Supplier using a 2 Channels Relay Module.






Who has done what beforehand?


The main idea came from a movie called The Dark Knight Rises where a device performed. This device was tied around Bruce's knee and made him get back to perform as Batman.


There I researched for some kind of device like this and I found this Thesis to applied a Mechatronic Engineering Degree. There is well explained all what I was looking for and I picked up some ides and concept to apply a my project.

Note: I didn't find any Leg Exoskeleton in Fab Academy repository as where I could search.






What materials and components will be required?... And process?


Next picture shows my Bill of Materials. I don't include pcb components because they are too many and their unitary price is very low.







Where will they come from?


Most of components are supplied by ULima Fab Lab. The 2 Linear Actuator was bought and imported by Amazon, and all screw and cap screw were bought at local supplier.






How much will it cost?


As it was showed at my BOM table this prototype cost me around 94.4 USD but if I had had to afford all components, it might cost me around 209.9 USD.
Note: This cost is to make the final prototype. To reach at this point Fab Lab supplied me with enough materials to test and deal with each part of the production.






What parts and systems will be made?


Evaluating the avaibility of each machine I used and process I can use to perform all learnt knowledge of past week I decide to process some parts with past machines.
The skeleton will be made with layers of 3mm MDF using Epilog machine due to some external situation. The board will be made using Roland machine, soldered with a Heat Gun and program wit a computer. Also using the computer could be made an application to control the project with Bluetooth. With 3D printers I could make hinges and the case for my microprocessor and switcher. Finally, using a drill I rectified each hole of layers and 3D print to perform well at assembly time.

Note: I started the production of some parts around week 10.





What procceses will be used?


Hand-Draw Design: I started sketching my idea using a pencil, a sheet of paper and some of my free time.

CAD Design: With this process I could make my draw more realistic. Also I could design my hinges based on others designs. Finally, using TinkerCad I could test the functionality of my boards and switcher distribution and performance.

3D Printing: At 3D printing process I could manufacture my hinges and cases of my project. I used this process for hinges instead to buy some because I previously tested someone design and was perfect performed.

Laser Cutting: At this part I could produce the layers of my final project using previous CAD design.

Electronic Design: Using Eagle program I designed all boards I need for this project. My main board is controlled with an AtMega 328p and it will recieve input signals from a switcher which is also design with EAGLE and from an App at an Android smartphone.

Electronic Production: I used a Heat Gun to soldered all components of my boards, a Multimeter to check if all parts are working well and my produced ISP to burn the Bootloader.

Embedded Programing and, Interface and Application: Using Arduino IDE I programmed all my AtomicMegatronic boards, 3, also I used App Inventor to create an App controlling for smartphones.



Note: As it was explained at last picture observation, I chose this process because we as Fab Laboratory were relocated to another building, we could move some machine to the new location but MultiCam is so massive than it could not be moved and is Out of Service.





What tasks need to be completed?


* At this time when I am doing this assignment : I'm finishing my 3D design ready to start with production part at Epilog Laser Cut machine.
* Hinges are designing at the same time of the first task to start with production at Replicators 3D printers.
* Board and switcher cases will be design and produce after I finish with the mechanism manufacturing.
* Smartphone App might be design this weekend.
* Buttons for switcher will be produced when I finish with Cases manufacturing.
* Smartphone App might be design this weekend.
* Wires and cables are being designed at this time using a plier, Dupont Cable and header of 2x2 and 2x3.
*Last assembly, programming, test and improve.





How will it be evaluated?


I tested the functionality of my project separated because there were some delays between arriving period of my linear actuators.

  • First, electrical connection.
    To make this video performed well I sketched the electronical connecting between my actuators, relays and adruino, and a switcher which is part of an Innovation course at university.


    And now comes the Arduino IDE code sketching.

    Now the real Arduino code I used. 

    int inp1=3;
int inp2=6;
int out1=8;
int out2=9;
int out3=10;
int out4=11;

void setup() {
  Serial.begin(9600);
  pinMode(inp1,INPUT);
 pinMode(inp2,INPUT);
  pinMode(out1,OUTPUT);
  pinMode(out2,OUTPUT);
  pinMode(out3,OUTPUT);
  pinMode(out4,OUTPUT);


}

void loop() {
  if(digitalRead(inp1)==1){
  digitalWrite(out1,HIGH);
    digitalWrite(out2,HIGH);
    digitalWrite(out3,HIGH);
    digitalWrite(out4,HIGH);
    }
    else if (digitalRead(inp2)==1){
      digitalWrite(out1,LOW);
    digitalWrite(out2,LOW);
    digitalWrite(out3,LOW);
    digitalWrite(out4,LOW);
    }
     }

    Note: I have 4 outputs because each Relay has 2 inputs.


    Then I tested how actuactor will perform with the block of layers and printed hinges.

  • This test made me realized that I need to integrate a auto blocking system just to hold printed hinges in their position.


  • Code was tested but it could not be test working with Android's App. It can be evaluated taking the time between I click on screen and the starting action.


  • Then, I added an emergency button at switcher that its porpuse is to stop all system in a dangerous situation and let help the person. If you click it twice, all system will be restart at beginnig status, EXTENDED.


  • Density of layers will be tested where assembly process finish, for what I will use a weight, and contract and extend action to analyze the force and deformation.


  • All 3D prints will be tested and rectify at assembly time.


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