|
|
@ -12,9 +12,9 @@ Usage: python createTemperatureLookup.py [options] |
|
|
|
Options: |
|
|
|
-h, --help show this help |
|
|
|
--rp=... pull-up resistor |
|
|
|
--t1=ttt:rrr low temperature temperature:resistance point (around 25C) |
|
|
|
--t2=ttt:rrr middle temperature temperature:resistance point (around 150C) |
|
|
|
--t3=ttt:rrr high temperature temperature:resistance point (around 250C) |
|
|
|
--t1=ttt:rrr low temperature temperature:resistance point (around 25 degC) |
|
|
|
--t2=ttt:rrr middle temperature temperature:resistance point (around 150 degC) |
|
|
|
--t3=ttt:rrr high temperature temperature:resistance point (around 250 degC) |
|
|
|
--num-temps=... the number of temperature points to calculate (default: 36) |
|
|
|
""" |
|
|
|
|
|
|
@ -50,25 +50,24 @@ class Thermistor: |
|
|
|
self.c3 = c |
|
|
|
self.rp = rp # pull-up resistance |
|
|
|
|
|
|
|
def res(self, adc): |
|
|
|
def resol(self, adc): |
|
|
|
"Convert ADC reading into a resolution" |
|
|
|
res = self.temp(adc)-self.temp(adc+1) |
|
|
|
return res |
|
|
|
|
|
|
|
def v(self, adc): |
|
|
|
def voltage(self, adc): |
|
|
|
"Convert ADC reading into a Voltage" |
|
|
|
return adc * VSTEP # convert the 10 bit ADC value to a voltage |
|
|
|
|
|
|
|
def r(self, adc): |
|
|
|
def resist(self, adc): |
|
|
|
"Convert ADC reading into a resistance in Ohms" |
|
|
|
r = self.rp * self.v(adc) / (VCC - self.v(adc)) # resistance of thermistor |
|
|
|
r = self.rp * self.voltage(adc) / (VCC - self.voltage(adc)) # resistance of thermistor |
|
|
|
return r |
|
|
|
|
|
|
|
def temp(self, adc): |
|
|
|
"Convert ADC reading into a temperature in Celcius" |
|
|
|
r = self.rp * self.v(adc) / (VCC - self.v(adc)) # resistance of thermistor |
|
|
|
lnr = log(r) |
|
|
|
Tinv = self.c1 + (self.c2*lnr) + (self.c3*pow(lnr,3)) |
|
|
|
l = log(self.resist(adc)) |
|
|
|
Tinv = self.c1 + self.c2*l + self.c3*pow(l,3) # inverse temperature |
|
|
|
return (1/Tinv) - ZERO # temperature |
|
|
|
|
|
|
|
def adc(self, temp): |
|
|
@ -87,7 +86,7 @@ def main(argv): |
|
|
|
t3 = 250 # high temperature in Kelvin (250 degC) |
|
|
|
r3 = 226.15 # resistance at high temperature (226.15 Ohm) |
|
|
|
rp = 4700; # pull-up resistor (4.7 kOhm) |
|
|
|
num_temps = int(36); # number of entries for look-up table |
|
|
|
num_temps = 36; # number of entries for look-up table |
|
|
|
|
|
|
|
try: |
|
|
|
opts, args = getopt.getopt(argv, "h", ["help", "rp=", "t1=", "t2=", "t3=", "num-temps="]) |
|
|
@ -130,11 +129,12 @@ def main(argv): |
|
|
|
print "const short temptable[NUMTEMPS][2] PROGMEM = {" |
|
|
|
|
|
|
|
for temp in temps: |
|
|
|
print " { (short) (%7.2f * OVERSAMPLENR ), %s\t}%s // v=%.3f\tr=%.3f\tres=%.3f degC/count" % ( t.adc(temp), temp, \ |
|
|
|
adc = t.adc(temp) |
|
|
|
print " { (short) (%7.2f * OVERSAMPLENR ), %4s }%s // v=%.3f\tr=%.3f\tres=%.3f degC/count" % (adc , temp, \ |
|
|
|
',' if temp != temps[-1] else ' ', \ |
|
|
|
t.v( t.adc(temp)), \ |
|
|
|
t.r( t.adc(temp)), \ |
|
|
|
t.res(t.adc(temp)) \ |
|
|
|
t.voltage(adc), \ |
|
|
|
t.resist( adc), \ |
|
|
|
t.resol( adc) \ |
|
|
|
) |
|
|
|
print "};" |
|
|
|
|
|
|
|