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@ -1,12 +1,8 @@ |
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#!/usr/bin/python |
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# |
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# Creates a C code lookup table for doing ADC to temperature conversion |
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# on a microcontroller |
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# based on: http://hydraraptor.blogspot.com/2007/10/measuring-temperature-easy-way.html |
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"""Thermistor Value Lookup Table Generator |
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Generates lookup to temperature values for use in a microcontroller in C format based on: |
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http://hydraraptor.blogspot.com/2007/10/measuring-temperature-easy-way.html |
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http://en.wikipedia.org/wiki/Steinhart-Hart_equation |
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The main use is for Arduino programs that read data from the circuit board described here: |
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http://make.rrrf.org/ts-1.0 |
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@ -19,7 +15,7 @@ Options: |
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--t1=ttt:rrr low temperature temperature:resistance point (around 25C) |
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--t2=ttt:rrr middle temperature temperature:resistance point (around 150C) |
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--t3=ttt:rrr high temperature temperature:resistance point (around 250C) |
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--num-temps=... the number of temperature points to calculate (default: 20) |
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--num-temps=... the number of temperature points to calculate (default: 36) |
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""" |
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from math import * |
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@ -86,15 +82,15 @@ class Thermistor: |
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return (r / (self.rp + r)) * (1024) |
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def main(argv): |
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rp = 4700; |
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t1 = 25; |
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r1 = 100000; |
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t2 = 150; |
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r2 = 1641.9; |
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t3 = 250; |
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r3 = 226.15; |
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num_temps = int(36); |
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"Default values" |
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t1 = 25 # low temperature in Kelvin (25 degC) |
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r1 = 100000 # resistance at low temperature (10 kOhm) |
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t2 = 150 # middle temperature in Kelvin (150 degC) |
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r2 = 1641.9 # resistance at middle temperature (1.6 KOhm) |
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t3 = 250 # high temperature in Kelvin (250 degC) |
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r3 = 226.15 # resistance at high temperature (226.15 Ohm) |
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rp = 4700; # pull-up resistor (4.7 kOhm) |
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num_temps = int(36); # number of entries for look-up table |
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try: |
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opts, args = getopt.getopt(argv, "h", ["help", "rp=", "t1=", "t2=", "t3=", "num-temps="]) |
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@ -102,7 +98,7 @@ def main(argv): |
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print str(err) |
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usage() |
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sys.exit(2) |
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for opt, arg in opts: |
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if opt in ("-h", "--help"): |
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usage() |
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@ -111,16 +107,16 @@ def main(argv): |
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rp = int(arg) |
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elif opt == "--t1": |
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arg = arg.split(':') |
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t1 = float( arg[0]) |
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r1 = float( arg[1]) |
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t1 = float(arg[0]) |
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r1 = float(arg[1]) |
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elif opt == "--t2": |
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arg = arg.split(':') |
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t2 = float( arg[0]) |
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r2 = float( arg[1]) |
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t2 = float(arg[0]) |
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r2 = float(arg[1]) |
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elif opt == "--t3": |
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arg = arg.split(':') |
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t3 = float( arg[0]) |
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r3 = float( arg[1]) |
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t3 = float(arg[0]) |
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r3 = float(arg[1]) |
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elif opt == "--num-temps": |
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num_temps = int(arg) |
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@ -136,8 +132,9 @@ def main(argv): |
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print "// Thermistor lookup table for Marlin" |
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print "// ./createTemperatureLookupMarlin.py --rp=%s --t1=%s:%s --t2=%s:%s --t3=%s:%s --num-temps=%s" % (rp, t1, r1, t2, r2, t3, r3, num_temps) |
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print "// Steinhart-Hart Coefficients: %.15g, %.15g, %.15g " % (t.c1, t.c2, t.c3) |
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print "//#define NUMTEMPS %s" % (len(temps)) |
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print "// Steinhart-Hart Coefficients: a=%.15g, b=%.15g, c=%.15g " % (t.c1, t.c2, t.c3) |
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print |
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print "#define NUMTEMPS %s" % (len(temps)) |
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print "const short temptable[NUMTEMPS][2] PROGMEM = {" |
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counter = 0 |
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@ -148,7 +145,7 @@ def main(argv): |
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else: |
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print " {(short)(%.2f*OVERSAMPLENR), %s}, // v=%s r=%s res=%s C/count" % ((t.adc(temp)), temp, t.v(t.adc(temp)), t.r(t.adc(temp)),t.res(t.adc(temp))) |
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print "};" |
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def usage(): |
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print __doc__ |
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