diff -r 000000000000 -r 2c8ba1964db7 createTemperatureLookup.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/createTemperatureLookup.py	Sat Nov 07 13:23:07 2015 +0100
@@ -0,0 +1,127 @@
+#!/usr/bin/python
+#
+# Creates a C code lookup table for doing ADC to temperature conversion
+# on a microcontroller
+# based on: http://hydraraptor.blogspot.com/2007/10/measuring-temperature-easy-way.html
+"""Thermistor Value Lookup Table Generator
+
+Generates lookup to temperature values for use in a microcontroller in C format based on: 
+http://hydraraptor.blogspot.com/2007/10/measuring-temperature-easy-way.html
+
+The main use is for Arduino programs that read data from the circuit board described here:
+http://make.rrrf.org/ts-1.0
+
+Usage: python createTemperatureLookup.py [options]
+
+Options:
+  -h, --help            show this help
+  --r0=...          thermistor rating where # is the ohm rating of the thermistor at t0 (eg: 10K = 10000)
+  --t0=...          thermistor temp rating where # is the temperature in Celsuis to get r0 (from your datasheet)
+  --beta=...            thermistor beta rating. see http://reprap.org/bin/view/Main/MeasuringThermistorBeta
+  --r1=...          R1 rating where # is the ohm rating of R1 (eg: 10K = 10000)
+  --r2=...          R2 rating where # is the ohm rating of R2 (eg: 10K = 10000)
+  --num-temps=...   the number of temperature points to calculate (default: 20)
+  --max-adc=...     the max ADC reading to use.  if you use R1, it limits the top value for the thermistor circuit, and thus the possible range of ADC values
+"""
+
+from math import *
+import sys
+import getopt
+
+class Thermistor:
+    "Class to do the thermistor maths"
+    def __init__(self, r0, t0, beta, r1, r2):
+        self.r0 = r0                        # stated resistance, e.g. 10K
+        self.t0 = t0 + 273.15               # temperature at stated resistance, e.g. 25C
+        self.beta = beta                    # stated beta, e.g. 3500
+        self.vadc = 5.0                     # ADC reference
+        self.vcc = 5.0                      # supply voltage to potential divider
+        self.k = r0 * exp(-beta / self.t0)   # constant part of calculation
+
+        if r1 > 0:
+            self.vs = r1 * self.vcc / (r1 + r2) # effective bias voltage
+            self.rs = r1 * r2 / (r1 + r2)       # effective bias impedance
+        else:
+            self.vs = self.vcc                   # effective bias voltage
+            self.rs = r2                         # effective bias impedance
+
+    def temp(self,adc):
+        "Convert ADC reading into a temperature in Celcius"
+        v = adc * self.vadc / 1024          # convert the 10 bit ADC value to a voltage
+        r = self.rs * v / (self.vs - v)     # resistance of thermistor
+        return (self.beta / log(r / self.k)) - 273.15        # temperature
+
+    def setting(self, t):
+        "Convert a temperature into a ADC value"
+        r = self.r0 * exp(self.beta * (1 / (t + 273.15) - 1 / self.t0)) # resistance of the thermistor
+        v = self.vs * r / (self.rs + r)     # the voltage at the potential divider
+        return round(v / self.vadc * 1024)  # the ADC reading
+
+def main(argv):
+
+    r0 = 10000;
+    t0 = 25;
+    beta = 3947;
+    r1 = 680;
+    r2 = 1600;
+    num_temps = int(20);
+    
+    try:
+        opts, args = getopt.getopt(argv, "h", ["help", "r0=", "t0=", "beta=", "r1=", "r2="])
+    except getopt.GetoptError:
+        usage()
+        sys.exit(2)
+        
+    for opt, arg in opts:
+        if opt in ("-h", "--help"):
+            usage()
+            sys.exit()
+        elif opt == "--r0":
+            r0 = int(arg)
+        elif opt == "--t0":
+            t0 = int(arg)
+        elif opt == "--beta":
+            beta = int(arg)
+        elif opt == "--r1":
+            r1 = int(arg)
+        elif opt == "--r2":
+            r2 = int(arg)
+
+    if r1:
+        max_adc = int(1023 * r1 / (r1 + r2));
+    else:
+        max_adc = 1023
+    increment = int(max_adc/(num_temps-1));
+            
+    t = Thermistor(r0, t0, beta, r1, r2)
+
+    adcs = range(1, max_adc, increment);
+#   adcs = [1, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 130, 150, 190, 220,  250, 300]
+    first = 1
+
+    print "// Thermistor lookup table for RepRap Temperature Sensor Boards (http://make.rrrf.org/ts)"
+    print "// Made with createTemperatureLookup.py (http://svn.reprap.org/trunk/reprap/firmware/Arduino/utilities/createTemperatureLookup.py)"
+    print "// ./createTemperatureLookup.py --r0=%s --t0=%s --r1=%s --r2=%s --beta=%s --max-adc=%s" % (r0, t0, r1, r2, beta, max_adc)
+    print "// r0: %s" % (r0)
+    print "// t0: %s" % (t0)
+    print "// r1: %s" % (r1)
+    print "// r2: %s" % (r2)
+    print "// beta: %s" % (beta)
+    print "// max adc: %s" % (max_adc)
+    print "#define NUMTEMPS %s" % (len(adcs))
+    print "short temptable[NUMTEMPS][2] = {"
+
+    counter = 0
+    for adc in adcs:
+        counter = counter +1
+        if counter == len(adcs):
+            print "   {%s, %s}" % (adc, int(t.temp(adc)))
+        else:
+            print "   {%s, %s}," % (adc, int(t.temp(adc)))
+    print "};"
+    
+def usage():
+    print __doc__
+
+if __name__ == "__main__":
+    main(sys.argv[1:])