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//
// Start of temperature lookup table
//
#define NUMTEMPS 20
short temptable[NUMTEMPS][2] = {
// { adc , temp }
{ 1 , 929 } ,
{ 54 , 266 } ,
{ 107 , 217 } ,
{ 160 , 190 } ,
{ 213 , 172 } ,
{ 266 , 158 } ,
{ 319 , 146 } ,
{ 372 , 136 } ,
{ 425 , 127 } ,
{ 478 , 119 } ,
{ 531 , 111 } ,
{ 584 , 103 } ,
{ 637 , 96 } ,
{ 690 , 88 } ,
{ 743 , 80 } ,
{ 796 , 71 } ,
{ 849 , 62 } ,
{ 902 , 50 } ,
{ 955 , 34 } ,
{ 1008 , 2 }
};
//
// End of temperature lookup table
//
//these our the default values for the extruder.
int extruder_speed = 128;
int extruder_target_celsius = 0;
int extruder_max_celsius = 0;
byte extruder_heater_low = 64;
byte extruder_heater_high = 255;
void init_extruder()
{
//default to room temp.
extruder_set_temperature(21);
pinMode(EXTRUDER_MOTOR_DIR_PIN, OUTPUT);
pinMode(EXTRUDER_MOTOR_SPEED_PIN, OUTPUT);
pinMode(EXTRUDER_HEATER_PIN, OUTPUT);
}
void extruder_set_direction(byte direction)
{
digitalWrite(EXTRUDER_MOTOR_DIR_PIN, direction);
}
void extruder_set_speed(byte speed)
{
analogWrite(EXTRUDER_MOTOR_SPEED_PIN, speed);
}
void extruder_set_cooler(byte speed)
{
analogWrite(EXTRUDER_FAN_PIN, speed);
}
void extruder_set_temperature(int temp)
{
extruder_target_celsius = temp;
extruder_max_celsius = (int)((float)temp * 1.1);
}
/**
* Samples the temperature and converts it to degrees celsius.
* Returns degrees celsius.
*/
int extruder_get_temperature()
{
if (EXTRUDER_THERMISTOR_PIN > -1)
return extruder_read_thermistor();
else if (EXTRUDER_THERMOCOUPLE_PIN > -1)
return extruder_read_thermocouple();
}
/*
* This function gives us the temperature from the thermistor in Celsius
*/
int extruder_read_thermistor()
{
int raw = extruder_sample_temperature(EXTRUDER_THERMISTOR_PIN);
int celsius = 0;
byte i;
for (i=1; i<NUMTEMPS; i++)
{
if (temptable[i][0] > raw)
{
celsius = temptable[i-1][1] +
(raw - temptable[i-1][0]) *
(temptable[i][1] - temptable[i-1][1]) /
(temptable[i][0] - temptable[i-1][0]);
if (celsius > 255)
celsius = 255;
break;
}
}
// Overflow: We just clamp to 0 degrees celsius
if (i == NUMTEMPS)
celsius = 0;
return celsius;
}
/*
* This function gives us the temperature from the thermocouple in Celsius
*/
int extruder_read_thermocouple()
{
return ( 5.0 * extruder_sample_temperature(EXTRUDER_THERMOCOUPLE_PIN) * 100.0) / 1024.0;
}
/*
* This function gives us an averaged sample of the analog temperature pin.
*/
int extruder_sample_temperature(byte pin)
{
int raw = 0;
//read in a certain number of samples
for (byte i=0; i<TEMPERATURE_SAMPLES; i++)
raw += analogRead(pin);
//average the samples
raw = raw/TEMPERATURE_SAMPLES;
//send it back.
return raw;
}
/*!
Manages motor and heater based on measured temperature:
o If temp is too low, don't start the motor
o Adjust the heater power to keep the temperature at the target
*/
void extruder_manage_temperature()
{
//make sure we know what our temp is.
int current_celsius = extruder_get_temperature();
//put the heater into high mode if we're not at our target.
if (current_celsius < extruder_target_celsius)
analogWrite(EXTRUDER_HEATER_PIN, extruder_heater_high);
//put the heater on low if we're at our target.
else if (current_celsius < extruder_max_celsius)
analogWrite(EXTRUDER_HEATER_PIN, extruder_heater_low);
//turn the heater off if we're above our max.
else
analogWrite(EXTRUDER_HEATER_PIN, 0);
}
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