View difference between Paste ID: HXQwwRbD and GEkjnVV6

 /*
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  * and open the template in the editor.
  */
 package iotdevice;
 
 import com.pi4j.io.i2c.I2CBus;
 import com.pi4j.io.i2c.I2CDevice;
 import com.pi4j.io.i2c.I2CFactory;
 import java.io.ByteArrayInputStream;
 import java.io.DataInputStream;
 //import com.pi4j.io.i2c.
 import java.io.IOException;
 
 /**
  *
  * @author Matteo
  */
 public class Sensor {
 
     //Raspberry Pi's I2C bus
     private static final int i2cBus = 1;
     // Device address
     // private static final int address = 0x50;
-    // RFID read address
+
-    private static final int rfidAddrRead = 0xA1;
+    // RFID addresses
-    private static final int rfidAddrWrite = 0xA0;
+    private static final int DEVICE_ADDRESS = 0x50;
 
     // Read RFID command
     private static final byte getRfidCmd = (byte) 0x01;
     private static final byte firmwareRfidCmd = (byte) 0xF0;
 
     //I2C bus
     I2CBus bus;
-    private I2CDevice sl030Read;
+
-    private I2CDevice sl030Write;
+
     private I2CDevice sl030;
     private DataInputStream sl030CalIn;
     private DataInputStream sl030In;
 
     public Sensor() {
 
         try {
             bus = I2CFactory.getInstance(I2CBus.BUS_1);
             System.out.println("Connected to bus OK!!!");
 
-            sl030Read = bus.getDevice(rfidAddrRead);
+
-            sl030Write = bus.getDevice(rfidAddrWrite);
+            sl030 = bus.getDevice(DEVICE_ADDRESS);
 
             System.out.println("Connected to device OK!!!");
             //Small delay before starting
            // Thread.sleep(500);
                  } catch (IOException e) {
             System.out.println("Exception: " + e.getMessage());
                  }
     }
 
     public String readRfid() throws IOException {
-        byte[] bytesTemp = new byte[4];
+
-        byte[] towrite= new byte[2];
+        byte[] writeBuffer= new byte[2];
         String result="EMPTY";
         try {
-            towrite[0]=(byte)0x01;
+            // SEND COMMAND TO DEVICE TO REQUEST FIRMWARE VERSION
-            towrite[1]=firmwareRfidCmd;
+            writeBuffer[0]=(byte)0x01;           // LENDTH (CMD+DATA)
-            sl030Write.write(towrite,0,2);
+            writeBuffer[1]=firmwareRfidCmd;      // COMMAND
             sl030.write(writeBuffer, 0, 2);
-           // sl030.r
+
-            int readTotal = sl030Read.read(bytesTemp, 0, 4);
+
-            System.out.println("Letti: " +readTotal);
+
-//            if (readTotal < 2) {
+            // READ DEVICE FIRMWARE RESPONSE
-//                System.out.format("Error: %n bytes read/n", readTotal);
+
-//                return "EMPTY";
+            // first just read in a single byte that represents the command+data payload
-//            }
+            int length = sl030.read();
 
             System.out.println("TOTAL BYTES AVAILABLE: " + length);
-            result = new String(bytesTemp);
+
             // if there are no remaining bytes (length == 0), then we can exit the function
             if(length <= 0) {
                 System.out.format("Error: %n bytes read for LENGTH/n", length);
                 return "EMPTY";
             }
 
             // if there is any length of remaining bytes, then lets read them now
             byte[] readBuffer = new byte[length];
             int readTotal = sl030.read(readBuffer, 0, length);
 
             // validate to ensure we got back at least the command and status bytes
             if (readTotal < 2) {
                 System.out.format("Error: %n bytes read/n", readTotal);
                 return "EMPTY";
             }
 
             byte command = java.lang.Byte.toUnsignedInt(readBuffer[0]);  // COMMAND BYTE
             byte status  = java.lang.Byte.toUnsignedInt(readBuffer[1]);  // STATUS BYTES
 
             // now we need to get the payload data (if there is any?)
             if(readTotal > 2){
               // we skip the first two bytes (command + status)
               result = new String(readBuffer, 2, readTotal - 2);
             }
 
             // what did we get?
             System.out.println("-- LENGTH BYTE READ  : " + length);
             System.out.println("-- COMMAND BYTE READ : " + command);
             System.out.println("-- STATUS BYTE READ  : " + status);
             System.out.println("-- DATA BYTES READ   : " + result);
 
 
 //            //sl030In = new DataInputStream(new ByteArrayInputStream(bytesTemp));
 //            //UT = sl030In.readUnsignedShort();
 
 
         } catch (IOException e) {
             System.out.println("Error: " + e.getMessage());
         } catch (InterruptedException e) {
             System.out.println("Interrupted Exception: " + e.getMessage());
         }
      //   System.out.println("Id RFID: " + result);
         return result;
     }
 
 }