Merge pull request #197 from ottk3/master

Prevent spamming UUIDs, remove RPI.GPIO module, add improved error handling and a cleanup method using atexit

scripts/Reader_RDM6300.py

@@ -12,44 +12,64 @@
 
 3.) Install dependecies
 -----------------------
-Be aware not to install the "serial" module, install "pyserial" instead and the RPi.GPIO module:
-    pip install pyserial RPi.GPIO
+Be aware not to install the "serial" module, install "pyserial" instead:
+    pip install pyserial
 
 4.) Replace the default Reader.py
 ---------------------------------
 Replace the Reader.py file with the Reader_RDM6300.py:
 mv Reader.py Reader_default.py; mv Reader_RDM6300.py Reader.py
 """
 
-
-import RPi.GPIO as GPIO
 import serial
 import string
+import atexit
 
 
 class Reader:
     def __init__(self):
         device = '/dev/ttyS0'
         baudrate = 9600
         ser_timeout = 0.1
-
-        GPIO.setmode(GPIO.BCM)
-        self.rfid_serial = serial.Serial(device, baudrate, timeout=ser_timeout)
+        self.last_card_id = ''
+        atexit.register(self.cleanup)
+        try:
+            self.rfid_serial = serial.Serial(device, baudrate, timeout=ser_timeout)
+        except serial.SerialException as e:
+            print(e)
+            exit(1)
 
     def readCard(self):
-        while True:
-            card_id = ''
-            try:
-                read_byte = self.rfid_serial.read()
-                if read_byte == b'\x02':
-                    while read_byte != b'\x03':
-                        read_byte = self.rfid_serial.read()
-                        card_id += read_byte.decode('utf-8')
-                    card_id = ''.join(x for x in card_id if x in string.printable)
-                    card_id
-                    return card_id
-
-            except ValueError as e:
-                print(e)
-                self.readCard()
+        byte_card_id = b''
+
+        try:
+            while True:
+                try:
+                    read_byte = self.rfid_serial.read()
+
+                    if read_byte == b'\x02':    # start byte
+                        while read_byte != b'\x03':     # end bye
+                            read_byte = self.rfid_serial.read()
+                            byte_card_id += read_byte
+
+                        card_id = byte_card_id.decode('utf-8')
+                        byte_card_id = ''
+                        card_id = ''.join(x for x in card_id if x in string.printable)
+
+                        # Only return UUIDs with correct length
+                        if len(card_id) == 12 and card_id != self.last_card_id:
+                            self.last_card_id = card_id
+                            self.rfid_serial.reset_input_buffer()
+                            return self.last_card_id
+
+                        else:   # wrong UUID length or aleady send that UUID last time
+                            self.rfid_serial.reset_input_buffer()
+
+                except ValueError as ve:
+                    print(ve)
+
+        except serial.SerialException as se:
+            print(se)
 
+    def cleanup(self):
+        self.rfid_serial.close()