Update create2.py

 Alternative wake up function using the Raspberry's GPIO Pin connected to the Baud Rate Change Pin of Roomba.
Flush of serial port after every read operation.
 Removed the 15 seconds margin included in the handle_auto_wakeup function. In Roomba series 700/800 it performs an unnecessary wake up (and the robot will enter despite all in energy save mode)

irobot/robots/create2.py

@@ -5,6 +5,7 @@
 import logging
 import serial
 from six import raise_from, iterbytes
+import RPi.GPIO as GPIO
 
 from irobot.openinterface.commands import set_mode_full, set_mode_passive, set_mode_safe, power_down, reset, start, stop, \
     drive, drive_direct, drive_pwm, seek_dock, set_baud, set_day_time, set_schedule, clean, clean_max, clean_spot, \
@@ -22,21 +23,40 @@
 
 
 class Create2(object):
-    def __init__(self, port, baud_rate=115200, timeout=1, auto_wake=True, enable_quirks=True):
+    def __init__(self, port, brc_pin=0, baud_rate=115200, timeout=1, auto_wake=True, enable_quirks=True):
         self._auto_wake = auto_wake
         self._oi_mode = MODES.OFF
         self._last_command_time = time()
-
+        
         self._enable_quirks = enable_quirks
         self._toggle_quirks()
 
         self.logger = logging.getLogger('Create2')
-
+
+        #If Roomba BRC pin is set , configure GPIO as wake up pin and configure correct wake function
+        self._brc_pin = brc_pin
+        if (self._brc_pin != 0):
+            self.wake = types.MethodType(Create2._wake_BRC, self)
+            GPIO.setmode(GPIO.BCM) 
+            GPIO.setwarnings(False)
+            GPIO.setup(self._brc_pin, GPIO.OUT)
+            GPIO.output(self._brc_pin, True)
+            sleep(1)
+            GPIO.output(self._brc_pin, False)
+            sleep(1)
+            GPIO.output(self._brc_pin, True)
+        else:
+            self.wake = types.MethodType(Create2._wake_RTS, self)
+
         self._attach_to_robot(port, baud_rate, timeout)
+
+
 
     def __del__(self):
         self.stop()
         self._serial_port.close()
+        if (self._brc_pin != 0):
+            GPIO.cleanup()
 
     def _attach_to_robot(self, port, baud_rate, timeout):
         try:
@@ -62,17 +82,27 @@ def _send(self, data):
         self._log_send(data)
 
         self._handle_auto_wake()
-        self._last_command_time = time()
+
+        #Roomba will sleep after 5 minutes of inactivity.
+        #Requesting a data packet is not considered as activity.
+        if (data[0] != 142):
+            self._last_command_time = time()
+
         self._serial_port.write(data)
 
     def _read_sensor_data(self, id):
+        #Flush input buffer to avoid inconsistent reads
+        self._serial_port.reset_input_buffer()
+
         self._send(request_sensor_data(id))
         size = RESPONSE_SIZES[id]
         data = self._serial_port.read(size)
-
+
+        #If no data was received, wake the roomba JIC
         if len(data) != size:
-            raise Exception("Did not receive data")
-
+            self.wake()
+            raise Exception('Received %d bytes but %d where expected', len(data), size)      
+
         self.logger.info('Received\n{0}'.format(self._format_data(data)))
 
         return data
@@ -82,8 +112,8 @@ def _handle_auto_wake(self):
             return
 
         now = time()
-        # wake the robot if the last command was sent any time after power save minus 15 seconds
-        if (now - self._last_command_time) >= POWER_SAVE_TIME - 15:
+        # wake the robot if the last command was sent any time after power saves
+        if (now - self._last_command_time) >= POWER_SAVE_TIME :
             self.wake()
 
     def _log_send(self, data):
@@ -150,16 +180,32 @@ def auto_wake(self):
     @auto_wake.setter
     def auto_wake(self, value):
         self._auto_wake = value
-
+        
     def wake(self):
+        pass
+
+    def _wake_BRC(self):
+        self.logger.info('Waking robot after {0:.2f} seconds of inactivity'.format(time() - self._last_command_time))
+        GPIO.output(self._brc_pin, False)
+        sleep(1)
+        GPIO.output(self._brc_pin, True)
+        sleep(1)
+        # after a wake up the robot sends some information. Flush it!
+        self._serial_port.reset_input_buffer()
+        self._last_command_time = time()
+
+    def _wake_RTS(self):
         self.logger.info('Waking robot after {0:.2f} seconds of inactivity'.format(time() - self._last_command_time))
         self._serial_port.setRTS(True)  # rts in pyserial 3.0
         sleep(1)
         self._serial_port.setRTS(False)
         sleep(1)
         self._serial_port.setRTS(True)
         sleep(1)
-
+        # after a wake up the robot sends some information. Flush it!
+        self._serial_port.reset_input_buffer()
+        self._last_command_time = time()           
+
     def start(self):
         self._send(start())
 
@@ -168,7 +214,7 @@ def start(self):
         if welcome_message is not None:
             self.logger.info('First 1024 characters of welcome message: {0}'.format(welcome_message))
         # flush anything after the first 1024 bytes
-        self._serial_port.flushInput()  # reset_input_buffer() in pyserial 3.0
+        self._serial_port.reset_input_buffer()
 
         self._verify_mode(MODES.PASSIVE)
 
@@ -250,7 +296,6 @@ def set_day_time(self, day=0, hour=0, minute=0):
             raise ValueError(_error_msg_range.format('hour'))
         if not self._is_valid_minute(minute):
             raise ValueError(_error_msg_range.format('minute'))
-
         self._send(set_day_time(day, hour, minute))
 
     def drive(self, velocity, radius):
@@ -634,9 +679,9 @@ def sensor_group107(self):
     def firmware_version(self):
         self.reset()
         sleep(5)
-        msg = self._serial_port.read(1024).decode('utf-8')
+        msg = self._serial_port.read(2048).decode('utf-8')
         self.start()
-        self._serial_port.flushInput()  # reset_input_buffer() in pyserial 3.0
+        self._serial_port.reset_input_buffer()  # reset_input_buffer() in pyserial 3.0
         return msg