Calculates the Steinhart-Hart coefficients given 3 known resistance temperature pairs.

coefficients.py

"""
Calculates the Steinhart-Hart coefficients for given resistance and temperature pairs.
"""
import sys
import math

titleString = """\
   ______      _      __            __      __ __         __    _____         _______     _          __    
  / __/ /____ (_)__  / /  ___ _____/ /_____/ // /__ _____/ /_  / ___/__  ___ / _/ _(_)___(_)__ ___  / /____
 _\ \/ __/ -_) / _ \/ _ \/ _ `/ __/ __/___/ _  / _ `/ __/ __/ / /__/ _ \/ -_) _/ _/ / __/ / -_) _ \/ __(_-<
/___/\__/\__/_/_//_/_//_/\_,_/_/  \__/   /_//_/\_,_/_/  \__/  \___/\___/\__/_//_//_/\__/_/\__/_//_/\__/___/
                                                                                                          
"""
print(titleString)
t1 = float(input("Enter temperature of thermistor in Kelvins at first reading: "))
r1 = float(input("Enter resistance of thermistor in Ohms at this temperature: "))
t2 = float(input("Enter temperature of thermistor in Kelvins at second reading: "))
r2 = float(input("Enter resistance of thermistor in Ohms at this temperature: "))
t3 = float(input("Enter temperature of thermistor in Kelvins at third reading: "))
r3 = float(input("Enter resistance of thermistor in Ohms at this temperature: "))

if(abs(t3 - t2) < 10 or abs(t3 - t1) < 10 or abs(t2 - t1) < 10):
	print("Readings are not far enough apart (< 10 degrees). Equation may be inaccurate due to this.")
	valid = False
	while (valid == False):
		confirmation = input("Would you like to continue? Enter \'y\' to continue or \'n\' to exit: ")
		if(confirmation == 'y'):
			valid = True
			break
		elif(confirmation == 'n'):
			valid = True
			sys.exit()
		else:
			valid = False

l1 = math.log(r1)
l2 = math.log(r2)
l3 = math.log(r3)

y1 = 1.0/t1
y2 = 1.0/t2
y3 = 1.0/t3

x2 = (y2 - y1)/(l2 - l1)
x3 = (y3 - y1)/(l3 - l1)

c = ((x3-x2)/(l3-l2))/(l1+l2+l3)
b = x2 - c*((l1**2) + (l1*l2) + (l2**2))
a = y1 - (b + ((l1**2)*c))*l1

print("A: ", a)
print("B: ", b)
print("C: ", c)