90 lines
2.7 KiB
Python
90 lines
2.7 KiB
Python
import time
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from statistics import mean
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from serial import Serial
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from serial.tools import list_ports
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from .config import DEFAULT_CALIB, DEFAULT_CALIB_WEIGHT, MOV_AVG_DEFAULTS
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class WeightReader:
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@property
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def value(self):
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return (self.current_raw_weight - self._tare) * self.calib_factor
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@property
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def calib_factor(self):
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return self._calib_factor
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@calib_factor.setter
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def calib_factor(self, value):
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self.calib_factor = value
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self._raw_reset_threshold = self.reset_threshold / value
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def __init__(self):
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self.running = True
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self.ports = [d.device for d in list_ports.grep('usbmodem')]
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self.serial = None
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self._calib_factor = DEFAULT_CALIB_WEIGHT / DEFAULT_CALIB
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self.window_size = MOV_AVG_DEFAULTS['window_size']
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self.reset_threshold = MOV_AVG_DEFAULTS['reset_threshold']
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self._raw_reset_threshold = MOV_AVG_DEFAULTS['reset_threshold'] / self._calib_factor
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self.ignore_samples = MOV_AVG_DEFAULTS['ignore_samples']
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self._tare = 0.0
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self.window = []
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self.current_raw_weight = 0
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self.ignored_samples = 0
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def scan_devices(self):
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self.ports = [d.device for d in list_ports.grep('usbmodem')]
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def connect(self, port, baudrate=115200):
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self.serial = Serial(port, baudrate)
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def disconnect(self):
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self.serial.close()
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self.serial = None
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def read_weights(self):
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while self.running:
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if self.serial is not None:
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try:
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line = self.serial.readline().decode('utf-8')
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raw_weight = int(line.split(',')[1])
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self.filter(raw_weight)
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except:
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pass
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else:
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time.sleep(1)
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def stop(self):
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self.running = False
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def filter(self, raw_weight):
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if len(self.window) < self.window_size:
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self.window.append(raw_weight)
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self.current_raw_weight = mean(self.window)
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else:
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out_of_threshold = abs(self.current_raw_weight - raw_weight) > self._raw_reset_threshold
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if out_of_threshold and\
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self.ignored_samples < self.ignore_samples:
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self.ignored_samples += 1
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elif out_of_threshold:
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self.ignored_samples = 0
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self.window = [raw_weight]
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self.current_raw_weight = raw_weight
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else:
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self.ignored_samples = 0
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self.window.append(raw_weight)
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self.current_raw_weight = mean(self.window)
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def tare(self):
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self._tare = self.current_raw_weight |