79 lines
1.7 KiB
Python
79 lines
1.7 KiB
Python
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"""
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Listen to serial, return most recent numeric values
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Lots of help from here:
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http://stackoverflow.com/questions/1093598/pyserial-how-to-read-last-line-sent-from-serial-device
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"""
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from threading import Thread
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import time
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import serial
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import struct
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last_received = ''
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profile = []
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PI_TS_MIN = 0
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PI_TS_MAX = 1
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PI_TL = 2
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PI_TP = 3
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PI_TIME_MAX = 4
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PI_RAMP_UP_MIN = 5
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PI_RAMP_UP_MAX = 6
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PI_RAMP_DOWN_MIN = 7
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PI_RAMP_DOWN_MAX = 8
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PI_TS_DURATION_MIN = 9
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PI_TS_DURATION_MAX = 10
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PI_TL_DURATION_MIN = 11
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PI_TL_DURATION_MAX = 12
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PI_TP_DURATION_MIN = 13
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PI_TP_DURATION_MAX = 14
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def receiving(ser):
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global last_received
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buffer = ''
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ser.write(chr(255))
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ser.flush()
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profile = struct.unpack("hhhhhhhhhhhhhhh", ser.read(30))
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ser.flushInput()
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while 1:
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ser.write(chr(254))
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ser.flush()
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last_received = ser.read(11)
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print repr(last_received)
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ser.flushInput()
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class SerialData(object):
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def __init__(self, init=50):
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try:
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self.ser = ser = serial.Serial(
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port='/dev/ttyUSB0',
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baudrate=9600, timeout=2)
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except serial.serialutil.SerialException:
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#no serial connection
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self.ser = None
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else:
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Thread(target=receiving, args=(self.ser,)).start()
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def next(self):
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if not self.ser:
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return 100 #return anything so we can test when Arduino isn't connected
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try:
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return int(struct.unpack("hhhhhb", last_received)[1])
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except Exception, e:
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print e
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return 0
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def __del__(self):
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if self.ser:
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self.ser.close()
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if __name__=='__main__':
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s = SerialData()
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for i in range(500):
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time.sleep(1)
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print s.next()
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