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Continous Servo angle control with if statement

[1 Reply]
- 01-Jun-2013 08:04 AM
- Forum: Integration and Hardware
Hello everyone. I am stuck on my project at the final part which is controlling a servo by reading xml feed and depending on the values it should turn several degrees. I am using a weather xml feed by yahoo which shows different wind speed attributes as speed, direction and etc. What i am doing is Im using only wind direction and speed in order to visualize it with LED's and and arrow for the direction. Everything works fine with the LED's , but when it comes to the servo I'm not quite sure what to do. It works alright with the Arduino sweeping example, but I use Firmata and i guess the code for it is a bit different. First I used standard Firmata to control the LED's but it wasn't good with the servo, so now Im using 2 arduino's one with Standard Firmata for the LEDs and one with Servo Firmata for the servo, noth assigned on different COM ports. Unfortunately when I try to program the servo it only gets faster or slower without being able to control the angle of it and when to stop. In arduino it works with their example, but in Firmata it seems that I can't adapt it so it does similar in Processing with Firmata. I've been stuck on this for 2 days already pls any help would be appreciated since I have to finish it by Monday

here is the code :

import processing.serial.*;

import cc.arduino.*;

Arduino arduino, arduino2;

final String URL = "http://weather.yahooapis.com/forecastrss?w=27764362";

final String WORD = "yweather:wind";

final String TOKEN = "\\W+";

int ledPin = 13;

int ledPin1 = 12;

int ledPin2 = 8;

int pos=0;

void setup() {

arduino = new Arduino(this, Arduino.list()[0], 57600);

arduino2 = new Arduino(this, Arduino.list()[1], 57600);

arduino.pinMode(ledPin, Arduino.OUTPUT);

arduino.pinMode(ledPin1, Arduino.OUTPUT);

arduino.pinMode(ledPin2, Arduino.OUTPUT);

arduino2.pinMode (9, Arduino.OUTPUT);

final String[] xml = loadStrings(URL);

int idx = 0;

for (; idx != xml.length; ++idx)

if ( xml[idx].contains(WORD) ) break;

if (idx == xml.length) {

println("Not found");

exit();

}

println("Index: " + idx);

println(xml[idx]);

final int[] info = int( xml[idx].split(TOKEN) );

final int dir = info[6];

final int spd = info[8];

println("Speed: " + spd);

println("Direction: " + dir);



if (spd < 5 ) {

arduino.digitalWrite(ledPin, Arduino.LOW);

arduino.digitalWrite(ledPin1, Arduino.LOW);

arduino.digitalWrite(ledPin2, Arduino.LOW);

}

if (spd >= 5 && spd <10) {

arduino.digitalWrite(ledPin, Arduino.HIGH);

arduino.digitalWrite(ledPin1, Arduino.LOW);

arduino.digitalWrite(ledPin2, Arduino.LOW);

}

if (spd >= 10 && spd <= 15) {

arduino.digitalWrite(ledPin, Arduino.HIGH);

arduino.digitalWrite(ledPin1, Arduino.HIGH);

arduino.digitalWrite(ledPin2, Arduino.LOW);

}

if (spd > 16) {

arduino.digitalWrite(ledPin, Arduino.HIGH);

arduino.digitalWrite(ledPin1, Arduino.HIGH);

arduino.digitalWrite(ledPin2, Arduino.HIGH);

}

println("3");



if (dir >= 10 && dir <= 25) {

println("4");



arduino2.analogWrite(9, 90);

delay(1500);

}

else if (dir > 340 && dir <= 360) {

println("Low speed");



arduino2.analogWrite(9, 80); //in this case 80 is controlling the speed, although I wanted to control the angle

delay(1500);

arduino2.analogWrite(9, 120); // same here

delay(1500);

println("5");

}

}

All those prinLn(1-5) are obviously just code checkers to see if there is something wrong with it, but i guess there isnt, its just that i cant control the angle or any other particular control over it other than it's speed, but it doesn't stop spinning till I unplug the usb most cases :)

I guess i need to insert somewher this part of the arduino example to make it move properly :

void loop()

{

for(pos = 0; pos < 180; pos += 1) // goes from 0 degrees to 180 degrees

{ // in steps of 1 degree

myservo.write(pos); // tell servo to go to position in variable 'pos'

delay(15); // waits 15ms for the servo to reach the position

}

But not quite sure since i tried, but I might not have programmed it properly .

Thanks!

If statement not doing what I need to do

[3 Replies]
- 26-May-2013 05:02 AM
- Forum: Programming Questions
Hello everyone Im kinda new to Processing, but I have to finish my Final project in the final year in uni :). What I am trying to do is to create a windmill on which there are 3 LED's attached on. Those LED's are controlled from xml feed and depending wind speed they glow(something like a glowing meter). I've managed to extract the exact data i needed from the xml(i got string numbers from the xml so I know which part of the line on which string number is so I can call just wind speed and I've transfered it into int) and etc, but when I try to make the if statement it doesn't do as said. So far I've plugged only 1 LED on 1 pin of the arduino, but as soon as it starts working with the if statement i will attach 2-3 more. Please take a look where Is my mistake, because i have like 5 days left :D

The code:

// Array to store titles

String[] titles;

import processing.serial.*;

PFont font;

import cc.arduino.*;

Arduino arduino;

int ledPin = 13;

Serial myPort;

int speed;

void setup() {

size(700, 300);

background(0);

noStroke();

//println(Arduino.list());

arduino = new Arduino(this, Arduino.list()[0], 57600);

arduino.pinMode(ledPin, Arduino.OUTPUT);

// Setup font

font = createFont("Arial", 12);

textFont(font, 12);

// xml = loadXML("http://weather.yahooapis.com/forecastrss?w=27764362");

String[] xml = loadStrings("http://weather.yahooapis.com/forecastrss?w=27764362");

println("Weather read");

int i = 0;

for (; i < xml.length; i++)

{

if (xml[i].contains("yweather:wind"))

break;

}

if (i == xml.length)

{

println("Not found");

exit();

}

String[] info = xml[i].split("\\W+"); // Split on everything not alphanumerical

println(info);

titles = new String[3];

for (int j = 0; j < info.length; j++)

{

if (info[j].equals("chill")) titles[0] = "chill = " + info[j+1];

if (info[j].equals("direction")) titles[1] = "direction = " + info[j+1];

if (info[j].equals("speed")) titles[2] = "speed = " + info[j+1];

}

println(Serial.list());

speed = int(info[8]);

speed = Integer.parseInt(info[8]); // No "int" part, not a declaration, just an assignment

println(""+ speed);

}

void loop() {

if (speed > 5)

arduino.digitalWrite(ledPin, Arduino.HIGH);

delay(500);

}

So lets say the xml value for "speed" is 10 and i make the statement to turn the LED if its more than 5. It should work, but nothing happens :(

Big thanks

Nick

How to parse a specific line from xml/rss feed

[18 Replies]
- 22-May-2013 11:01 AM
- Forum: Programming Questions
Hello everyone
       I've been trying to make a program that makes several LED's turn on and off depending on xml feed's data. Unfortunately i am very new to Processing and i have like a week to finish this project, but problems keep occuring everywhere as usual :) . Anyway to the point so far one of the main problems is that half of the things I am trying to do(such as turn LED on and off) works on Processing version 1.5 and part of my xml parsing code works on version 2+. Currently I am trying to run this code in order to get the xml info I want :

The code:

/**

* Loads RSS feed and visualizes the titles in a very simple manner.

* Color and bar depend on the length of the corresponding title.

*

* (c) 2008 Till Nagel, btk.tillnagel.com

*/

// Array to store titles

String[] titles;

XML xml;

XML[] children;

PFont font;

void setup() {

size(700, 300);

background(0);

noStroke();



// Setup font

font = loadFont("Calibri-12.vlw");

textFont(font, 12);



xml = loadXML("http://weather.yahooapis.com/forecastrss?w=27764362");

children = xml.getChildren("channel/yweather:wind"); // the program reads the xml content without yweather:wind, but i need exactly this bit, so thats why i left it so you can see that I've tried

titles = new String[children.length];

for (int i = 0; i < children.length; i++) {

String title = children[i].getContent();

titles[i] = title;

}

}

void draw() {

background(255);



// Draw all titles with bars and colors depending on its length

for (int i = 0; i < titles.length; i++) {

float y = (i+1) * 15;

fill(255 - constrain(titles[i].length(), 0, 255));

rect(8, y - 11, 14, 14);



fill(127, 100);

rect(23, y - 11, titles[i].length() * 2, 14);



fill(0, 220);

text(titles[i], 26, y);

}

}

So basically what I need to do is get the "yweather:wind" line of the XML code which it doesn show and get wind speed and wind direction attributes and use those values later in order to control the LED's . I've tried all possible getChild commands such as (channel/yweather:wind, channel/yweather: and etc) Unfortunately this seems to be harder than i expected considering all the version incompatibility. I've connected everything through Arduino I also tried using Firmata library which works only in ver 1.5 sort of :D

PS: as you can probably see one part of the code doesnt do anything specific for xml reading it just colors the text, but this is an example which Im using and if i delete this bit of the code i just get a black screen.



I would appreciate any help since this is my final project and the time is passing by quickly

Thanks

Nick

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