82 lines
2.0 KiB
Python
Executable File
82 lines
2.0 KiB
Python
Executable File
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'''
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Electronic Scale measure methods
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'''
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import time
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try:
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import serial
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except:
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print('Warning: missing pyserial module!')
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from decimal import Decimal
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from PyQt5.QtCore import QThread, pyqtSignal
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ZERO_VALUES = [b'00.000\n', b'\r00.000\n']
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FAKE_WEIGHT = b'01.500\n'
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MAX_RANGE_ATTEMPT = 30
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class ScaleReader(QThread):
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"""
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Electronic Scale Reader Class
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"""
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sigSetDevice = pyqtSignal()
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sigSetWeight = pyqtSignal()
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sigCancelAction = pyqtSignal()
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def __init__(self, device_path='/dev/ttyUSB0', fake=False):
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QThread.__init__(self)
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self.fake = fake
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self.device = device_path
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try:
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self.scale = serial.Serial(self.device)
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except:
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print('Error: serial device not found!')
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def run(self):
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values = []
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counter = 0
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self.best_weight = Decimal(0)
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if self.fake:
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self._run_fake()
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return
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try:
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self.scale = serial.Serial(self.device)
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except:
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print('Error: serial device not found!')
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return
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while counter <= MAX_RANGE_ATTEMPT:
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read_value = self.scale.readline()
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if read_value in ZERO_VALUES:
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continue
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counter += 1
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weight = read_value.decode("utf-8")
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weight = weight.replace('\n\r', '')
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weight = weight.encode("ascii").decode()
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try:
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weight = Decimal(weight)
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except:
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continue
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values.append(weight)
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self.scale.close()
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if values:
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self.best_weight = str(max(values))
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self.sigSetWeight.emit()
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def _run_fake(self):
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self.scale = 'Fake Electronic Scale'
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self.sigSetDevice.emit()
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time.sleep(3)
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self.best_weight = FAKE_WEIGHT
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self.sigGetWeight.emit()
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def reset_zero(self):
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self.best_weight = None
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def onClose(self):
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if hasattr(self, 'scale'):
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self.scale.close()
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