23. November 2011

In einem weiteren Modul in diesem Kurs, schauten wir einen Beschleunigungsensor an. Mit dem Arduino lesen wir den Sensor aus und ürgeben dann die Daten an Processing, welches errechnet in welcher Lage sich der Sensor befindet. As kleines Feature habe ich eine automatische Kalibrierung für den Sensor eingebaut. Arduino

// Includes
#include <Wire.h>
#include <MMA_7455.h>

// Objeczs
MMA_7455 sensor = MMA_7455();

// Variables
char xNew, yNew, zNew;
char xOld, yOld, zOld;

// Setup
void setup()
{
  // Begin Serial
  Serial.begin(9600);
  
  // Set Sensitivity
  sensor.initSensitivity(2);
  
  // Wait
  delay(200);
  
  // Read Raw Orientation
  char x = sensor.readAxis('x');
  char y = sensor.readAxis('y');
  char z = sensor.readAxis('z');
  
  // Calibrate
  sensor.calibrateOffset(0-x,0-y,64-z);
}
 
void loop()
{
  xNew = sensor.readAxis('x');
  yNew = sensor.readAxis('y');
  zNew = sensor.readAxis('z');
  
  xNew = (0.5*xOld) + (0.5*xNew);
  yNew = (0.5*yOld) + (0.5*yNew);
  zNew = (0.5*zOld) + (0.5*zNew);
  
  xOld = xNew;
  yOld = yNew;
  zOld = zNew;
  
  printOrientation(xNew,yNew,zNew);
}

// Print Orientation to Serial
void printOrientation(char x, char y, char z)
{
  Serial.print(x,DEC);
  Serial.print("\t");
  Serial.print(y,DEC);
  Serial.print("\t");
  Serial.print(z,DEC);
  Serial.print("\t");
  Serial.println();
}

Processing:

// Includes
import processing.serial.*;

// Objects
Serial serial;

// Variables
int rawX, rawY, rawZ;
int accX, accY, accZ;
String lastMode = "";

// Setup Routine
void setup()
{
  background(0);
  size(500,500,P3D);
  frameRate(30);
  println(serial.list());
  serial = new Serial(this,serial.list()[0],9600);
  loop();
}

// Draw Loop
void draw()
{ 
  // Set Background
  background(0);
  
  // Create String
  String str = accX+""+accY+""+accZ;
  
  // Check
  if(!lastMode.equals(str))
  {
    // Conditions
    if(str.equals("002")) {
      println("Normal");
    } else if(str.equals("200")) {
      println("Links gekippt");
    } else if(str.equals("100")) {
      println("Rechts gekippt");
    } else if(str.equals("010")) {
      println("Hinten gekippt");
    } else if(str.equals("020")) {
      println("Vorne gekippt");
    } else if(str.equals("001")) {
      println("Nach Unten");
    }
    
    // Save
    lastMode = str;
  }
}

// Serial Data Event
void serialEvent(Serial data)
{
  // Check for Data
  if (data.available() > 0)
  {
    // Get whole String
    String completeString = data.readStringUntil(10);
    
    // Check String
    if (completeString != null)
    {
      // Remove whitespace
      trim(completeString);
      
      // Split
      String seperateValues[] = split(completeString,"\t");
      
      // Set Variables
      rawX = int(seperateValues[0]);
      rawY = int(seperateValues[1]);
      rawZ = int(seperateValues[2]);
      
      // Calculate
      accX = calc(rawX);
      accY = calc(rawY);
      accZ = calc(rawZ);
    }
  }
}

// Calculate Value
int calc(int in)
{
  if(in >= 40) { return 2; }
  if(in <= -40) { return 1; }
  return 0;
}

// Stop Sketch
void stop()
{
  // Close Serial Connection
  serial.stop();
  super.stop();
}