Interface and Application Programming

COUNTDOWN

The assignment this week was to write an application that interfaces with an input &/or output device that you made.

• In this weeks assignment, processing would be used to display the values that the serial monitor of the Arduino IDE would display in a form where the animation of the values is based on the code in processing.
• In my case I decided to download a template of a Radar scanner, where the Arduino code would contain functions for an Ultrasonic sensor and a servo motor. Both of them would feed the serial monitor values.
1. The ultrasonic sensor would display the distance
2. The servo would display its current position.
• The servo is set to sweep from 0 to 180 degrees and in return the processing javascript animation would show a bar that sweeps from 0 to 180 degrees. This is where the Ultrasonic sensor would have a role. The bar is green when there is nothing obstructing the ultrasonic sensor and once it is and has a value below 40cm it would display that distance in red and keep it in the background until it sweeps back and confirms it is clear.
• Below is the code of the Arduino



#include<Servo.h> int trigPin=9; int echoPin=10; long duration; int distance; Servo servo; void setup() { pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); Serial.begin(9600); servo.attach(8); } void loop() { for(int i=0;i<=180;i++) { servo.write(i); delay(100); distance=calculateDistance(); Serial.print(i); Serial.print(","); Serial.print(distance); Serial.print("."); } for(int i=180;i>0;i--) { servo.write(i); delay(100); distance=calculateDistance(); Serial.print(i); Serial.print(","); Serial.print(distance); Serial.print("."); } } int calculateDistance() { digitalWrite(trigPin,LOW); delayMicroseconds(2); digitalWrite(trigPin,HIGH); delayMicroseconds(10); digitalWrite(trigPin,LOW); duration=pulseIn(echoPin,HIGH); distance=duration*0.034/2; return distance; }



• As you can see the loop specifies that the ultrasonic sensor is always reading and sending data. Whereas the servo would go from 0 to 180 degrees and then from a 180 to 0 degrees.
• Now for the processing code:
• The processing code is basically drawing the animation of the application desired and uses the values that are sent back from the arduino and its sensors to move these animations based on what it is set to do. The main things that need to be adjusted in the code are the screen resolutions as it cannot be scaled once it is played and specifying the serial port where the arduino is connected (check the port on the arduino IDE to get this if you face difficulties).
• Code Below:



import processing.serial.*; import java.awt.event.KeyEvent; import java.io.IOException; Serial myPort; String angle=""; String distance=""; String data=""; String noObject; float pixelsDistance; int iAngle,iDistance; int index1=0,index2=0; PFont orcFont; void setup() { size(1900,1200); smooth(); myPort=new Serial(this,"/dev/cu.usbmodem1421",9600); myPort.bufferUntil('.'); orcFont=loadFont("OCRAExtended-30.vlw"); } void draw() { fill(98,245,31); textFont(orcFont); noStroke(); fill(0,4); rect(0,0,width,1010); fill(98,245,31); drawRadar(); drawLine(); drawObject(); drawText(); } void serialEvent(Serial myPort) { data=myPort.readStringUntil('.'); data=data.substring(0,data.length()-1); index1=data.indexOf(","); angle=data.substring(0,index1); distance=data.substring(index1+1,data.length()); iAngle=int(angle); iDistance=int(distance); } void drawRadar(){ pushMatrix(); translate(760,800); noFill(); strokeWeight(2); stroke(98,245,31); arc(0,0,1400,1400,PI,TWO_PI); arc(0,0,1100,1100,PI,TWO_PI); arc(0,0,800,800,PI,TWO_PI); arc(0,0,500,500,PI,TWO_PI); line(-760,0,760,0); line(0,0,-760*cos(radians(30)),-760*sin(radians(30))); line(0,0,-760*cos(radians(60)),-760*sin(radians(60))); line(0,0,-760*cos(radians(90)),-760*sin(radians(90))); line(0,0,-760*cos(radians(120)),-760*sin(radians(120))); line(0,0,-760*cos(radians(150)),-760*sin(radians(150))); line(-760*cos(radians(30)),0,760,0); popMatrix(); } void drawObject() { pushMatrix(); translate(760,800); // moves the starting coordinats to new location strokeWeight(9); stroke(255,10,10); // red color pixelsDistance = iDistance*22.5; // covers the distance from the sensor from cm to pixels // limiting the range to 40 cms if(iDistance<40){ // draws the object according to the angle and the distance line(pixelsDistance*cos(radians(iAngle)),-pixelsDistance*sin(radians(iAngle)),750*cos(radians(iAngle)),-750*sin(radians(iAngle))); } popMatrix(); } void drawLine() { pushMatrix(); strokeWeight(9); stroke(30,250,60); translate(760,800); line(0,0,750*cos(radians(iAngle)),-750*sin(radians(iAngle))); popMatrix(); } void drawText() { pushMatrix(); if(iDistance>40) { noObject="Out ofRange"; } else{ noObject="In Range"; } fill(0,0,0); noStroke(); rect(0, 1010, width, 1080); fill(98,245,31); textSize(25); text("10cm",1180,990); text("20cm",1380,990); text("30cm",1580,990); text("40cm",1780,990); textSize(30); text("Object: " + noObject,15,100); text("Angle: " + iAngle +" °",400, 50); text("Distance: ", 13,50); if(iDistance<40) { text(" " + iDistance +" cm",30,50); } textSize(15); fill(98,245,60); translate(761+760*cos(radians(30)),782-760*sin(radians(30))); rotate(-radians(-60)); text("30°",0,0); resetMatrix(); translate(754+760*cos(radians(60)),784-760*sin(radians(60))); rotate(-radians(-30)); text("60°",0,0); resetMatrix(); translate(745+760*cos(radians(90)),790-760*sin(radians(90))); rotate(radians(0)); text("90°",0,0); resetMatrix(); translate(735+760*cos(radians(120)),803-760*sin(radians(120))); rotate(radians(-30)); text("120°",0,0); resetMatrix(); translate(740+760*cos(radians(150)),818-760*sin(radians(150))); rotate(radians(-60)); text("150°",0,0); popMatrix(); }



• Two things to take note of when it comes to the processing code:
1. Make sure you add the "import processing.serial.*;" at the beginning so it knows it needs to communicate with the arduino through the serial port that is specified.
2. When you play the code as in run the application, make sure thge serial monitor of the Arduino IDE is closed because it would not work. You could use it before running the java code to make sure the values are displayed correctly.
• Here is a demo video to showcase this process although the servo is not included, the serial monitor values is tricked into thinking the servo is connected and is going through the respective angles it should have.





• And another test this time with my PCB from Input/Output week. Make sure to change the port in processing and specify pins in the arduino code.

Downloads