1  # SPDX-FileCopyrightText: 2019 Anne Barela for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  import time
 6  import random
 7  class FlowMeter():
 8    PINTS_IN_A_LITER = 2.11338
 9    SECONDS_IN_A_MINUTE = 60
10    MS_IN_A_SECOND = 1000.0
11    displayFormat = 'metric'
12    beverage = 'beer'
13    enabled = True
14    clicks = 0
15    lastClick = 0
16    clickDelta = 0
17    hertz = 0.0
18    flow = 0 # in Liters per second
19    thisPour = 0.0 # in Liters
20    totalPour = 0.0 # in Liters
21  
22    def __init__(self, displayFormat, beverage):
23      self.displayFormat = displayFormat
24      self.beverage = beverage
25      self.clicks = 0
26      self.lastClick = int(time.time() * FlowMeter.MS_IN_A_SECOND)
27      self.clickDelta = 0
28      self.hertz = 0.0
29      self.flow = 0.0
30      self.thisPour = 0.0
31      self.totalPour = 0.0
32      self.enabled = True
33  
34    def update(self, currentTime):
35      self.clicks += 1
36      # get the time delta
37      self.clickDelta = max((currentTime - self.lastClick), 1)
38      # calculate the instantaneous speed
39      if (self.enabled == True and self.clickDelta < 1000):
40        self.hertz = FlowMeter.MS_IN_A_SECOND / self.clickDelta
41        self.flow = self.hertz / (FlowMeter.SECONDS_IN_A_MINUTE * 7.5)  # In Liters per second
42        instPour = self.flow * (self.clickDelta / FlowMeter.MS_IN_A_SECOND)  
43        self.thisPour += instPour
44        self.totalPour += instPour
45      # Update the last click
46      self.lastClick = currentTime
47  
48    def getBeverage(self):
49      return str(random.choice(self.beverage))
50  
51    def getFormattedClickDelta(self):
52       return str(self.clickDelta) + ' ms'
53    
54    def getFormattedHertz(self):
55       return str(round(self.hertz,3)) + ' Hz'
56    
57    def getFormattedFlow(self):
58      if(self.displayFormat == 'metric'):
59        return str(round(self.flow,3)) + ' L/s'
60      else:
61        return str(round(self.flow * FlowMeter.PINTS_IN_A_LITER, 3)) + ' pints/s'
62    
63    def getFormattedThisPour(self):
64      if(self.displayFormat == 'metric'):
65        return str(round(self.thisPour,3)) + ' L'
66      else:
67        return str(round(self.thisPour * FlowMeter.PINTS_IN_A_LITER, 3)) + ' pints'
68    
69    def getFormattedTotalPour(self):
70      if(self.displayFormat == 'metric'):
71        return str(round(self.totalPour,3)) + ' L'
72      else:
73        return str(round(self.totalPour * FlowMeter.PINTS_IN_A_LITER, 3)) + ' pints'
74  
75    def clear(self):
76      self.thisPour = 0;
77      self.totalPour = 0;