View difference between Paste ID: RbDjLFjM and HW2LFCb5

-On 7/13/15 John Bohlhuis contribute his own Python code that he is using to automate the reading of distance values.
+# maxSonarTTY.py
-We gladly share this for your use in your projects.
+
-Thank you John for sharing.
+import serial
 import re
 
-***************************************************************************
+class MaxSonar( serial.Serial ):
-First, the Python module that does the actual work:
+    def __init__( self, port ):
-***************************************************************************
+        super().__init__( port=port, baudrate=9600, timeout=0.5 )
 
-#!/usr/bin/python3
+    def measure( self ):
-# Filename: maxSonarTTY.py
+        self.reset_input_buffer()
 
-# Reads serial data from Maxbotix ultrasonic rangefinders
+        data = self.read_until( b'\r', size=5 )
-# Gracefully handles most common serial data glitches
+
-# Use as an importable module with "import MaxSonarTTY"
+        if re.fullmatch( rb'\d*\r', data ):
-# Returns an integer value representing distance to target in millimeters
+            # partial line received, wait for next one
             data = self.read_until( b'\r', size=5 )
-from time import time
+
-from serial import Serial
+        if len( data ) < 5 and not data.endswith( b'\r' ):
             raise RuntimeError( "Timeout while waiting for data" )
-serialDevice = "/dev/ttyAMA0" # default for RaspberryPi
+
-maxwait = 3 # seconds to try for a good reading before quitting
+        m = re.fullmatch( rb'R(\d+)\r', data )
         if not m:
-def measure(portName):
+            raise RuntimeError( "Garbage data received: %r" % data )
-    ser = Serial(portName, 9600, 8, 'N', 1, timeout=1)
+        data = m.group( 1 )
-    timeStart = time()
+
-    valueCount = 0
+        return int( data )  # measurement in inches (0-255)
 
-    while time() < timeStart + maxwait:
+
-        if ser.inWaiting():
+# maxSonarTTY-example.py
-            bytesToRead = ser.inWaiting()
+
-            valueCount += 1
+
-            if valueCount < 2: # 1st reading may be partial number; throw it out
+from maxSonarTTY import MaxSonar
-                continue
+
-            testData = ser.read(bytesToRead)
+sonar = MaxSonar( "/dev/ttyS2" )
-            if not testData.startswith(b'R'):
+
-                # data received did not start with R
+try:
-                continue
+    while True:
-            try:
+        distance = sonar.measure()
-                sensorData = testData.decode('utf-8').lstrip('R')
+        print( "distance =", distance, "inch" )
-            except UnicodeDecodeError:
+
-                # data received could not be decoded properly
+        sleep( 1 )
-                continue
+
-            try:
+except KeyboardInterrupt:
-                mm = int(sensorData)
+    pass