Week 16

Interface and Application Programming.

ASSIGNMENT:

1.) write an application that interfaces with an input or output device that you made.

This week we had to write an application that interfaces with a output or input device. In my case I decided to work with a pair of servos, because lately I've been working with these output devices for my final project.

It is the first time I use tools to develop software, for that reason I have recommended to start with "PROCESSING" because is a good software for beginners in software development.

DOCUMENTATION

- Tools

In this assignment I used Arduino IDE + Processing.

With "Arduino IDE" I've written the code to load my Fabduino and control the servos.

And with "Processing" I have written the code to develop the interface that will allow me to manage servos from my computer and mouse.

- Arduino IDE.

First in "ArduinoIDE" I had to upload the code to my Fabduino for the servo motors, then is important to close the serial monitor before to open "Processing".

Arduino Code for servo motor:

  • #include < Servo.h>
  • Servo yservo; Servo xservo; // servos for x and y
  • int ypos = 0;
  • int xpos= 0;
  • void setup(){
  • xservo.attach(10); //(Digital pin 10) for the x servo
  • yservo.attach(11); //(Digital pin 11) for the y server
  • Serial.begin(19200); // 19200 is the rate of communication
  • Serial.println("Haupei"); // some output for debug purposes.
  • }
  • void loop() {
  • static int v = 0;
  • if ( Serial.available()) {
  • char ch = Serial.read();
  • switch(ch) {
  • case '0'...'9':
  • v = v * 10 + ch - '0';
  • break;
  • case 'x': // if it's x
  • xservo.write(v);
  • v = 0;
  • break;
  • case 'y':
  • yservo.write(v);
  • v = 0;
  • break;
  • }
  • }
  • }
- Processing.

I've started from basic examples, trying to undestand the code. At the beginning, very similar to Arduino CODE, there's a list of the mentioned libraries. As you can see, you should import several libraries, but the main important surely is the "import processing.serial" that basically it's a class for sending and receiving data using the serial communication protocol.

Processing Code for servo controller interface:

  • import processing.serial.*;
  • int xpos=90; // set x servo's value to mid point (0-180);
  • int ypos=90; // and the same here
  • Serial port; // The serial port we will be using
  • void setup()
  • {
  • size(360, 360);
  • frameRate(100);
  • println(Serial.list());
  • port = new Serial(this, Serial.list()[1], 19200);
  • }
  • void draw()
  • {
  • fill(0,0,0);
  • rect(0,0,360,360);
  • fill(110,110,110); //rgb gray
  • rect(180, 175, mouseX-180, 25); //xpos, ypos, width, height
  • fill(58,95,205); // rgb blue
  • rect(175, 180, 25, mouseY-180);
  • update(mouseX, mouseY);
  • }
  • void update(int x, int y)
  • {
  • //Calculate servo postion from mouseX
  • xpos= x/2;
  • ypos = y/2;
  • //Output the servo position ( from 0 to 180)
  • port.write(xpos+"x");
  • port.write(ypos+"y");
  • }

After some tests and the correct modification of certain codes, I got the following:

- Final Results.

In the end, I got the following circuit to test my interface. The video shows the operation of the interface with the entire circuit.

- Mistakes and learned:.

- The servos operate between 4.5 V and 9V, but the 5 V provided by the Fabduino was not enough to make them work. That's why I had to resort to an external source of 9 V.

- Digital pins 10 and 11 of Fabduino are sending signals to the servos movement.

- To run the software in Processing , it is important that the "Serial Monitor" of Arduino IDE is closed.

- Only the power supply gnd and Fabduino are connected to each other.

You can download my files here.

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SELF EVALUATION
WHAT WORKED:

- Move the servos through an interface on a computer.

- A code was achieved through a software that allows the control and movement of a servo.

WHAT DID NOT WORK:

- For a moment I could not feed the servos with integrated Fabduino 5V source, I had to resort to an external source.

- Because my first contact with the development of software, it took me some time to understand and apply the concepts of programming. That's why I could not achieve a more user friendly interface.

THINGS TO IMPROVE:

- Experiment more with programming and a more friendly and graphics to identify and understand the operating values servo interface.

I'm currently taking this course in FAB LAB TECSUP, in Lima-Perú, through CIDI FADA UNA with the support of CONACYT and PARQUE TECNOLOGICO ITAIPU FOUNDATION

©DESIGNED AND BUILD BY FABIO IBARRA - FAB ACADEMY 2016

EMAIL: fabioibarrab@gmail.com