temp_queue.py

import statistics

'''
Class to track temperature averages coming from the ADC and 
handle errors gracefully (hopefully).  
'''

class TempQueue():
	def __init__(self, qlength=10, units='F'):
		self.queue = []
		self.units = units

		if(qlength < 2):
			self.qlength = 2 # Set minimum qlength to 2
		else: 
			self.qlength = qlength
		
		if(units == 'F'):
			self.stdev_max = 4.75  # Standard Deviation Maximum for degrees F
		else:
			self.stdev_max = 2.25  # Standard Deviation Maximum for degrees C
		self.last_average = 0

	def enqueue(self, value):
		while (len(self.queue) < (self.qlength + 1)):
			self.queue.insert(0, value)
		self.queue.pop()
		return(self.average())

	def average(self):
		if(len(self.queue) < self.qlength):
			# Handle case if queue isn't full 
			self.last_average = 0
			return(0)
		elif(self.last_average == 0):
			# Handle case if lastaverage isn't initialized
			average = (sum(self.queue) / self.qlength)
			self.last_average = average
			if(self.units == 'F'):
				return(int(average))  # Give integer for F units
			else: 
				return(round(average, 1))  # Give one digit of decimal for C units
		else:
			# Handle normal case
			# Get standard deviation from temperatures in the queue
			stdev = statistics.stdev(self.queue)
			if(stdev < self.stdev_max):
				# If the standard deviation is less than the max deviation, calculate the average temperature as normal
				average = (sum(self.queue) / self.qlength)
				self.last_average = average
			else:
				# If the standard deviation exceeds the max deviation, keep the last average value
				average = self.last_average

			if(self.units == 'F'):
				return(int(average))  # Give integer for F units
			else: 
				return(round(average, 1))  # Give one digit of decimal for C units