From e4af5e82f26fab59bb2bda540e1673317f48ce8a Mon Sep 17 00:00:00 2001 From: kliment Date: Mon, 4 Jul 2011 16:17:19 +0200 Subject: Rename to Sprinter --- Sprinter/createTemperatureLookup.py | 127 ++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 Sprinter/createTemperatureLookup.py (limited to 'Sprinter/createTemperatureLookup.py') diff --git a/Sprinter/createTemperatureLookup.py b/Sprinter/createTemperatureLookup.py new file mode 100644 index 0000000..e60a490 --- /dev/null +++ b/Sprinter/createTemperatureLookup.py @@ -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:]) -- cgit v1.2.1