Hello, I'm having trouble controlling a motor with if() statements from thermocouple output. Thermocouple takes a reading and is supposed to spin opposite directions based on high or low temperature. If temp is within a range the motor is off, spin is opposite depending on whether temp is above max or below minimum.
For some reason, the motor always spins, and always at max speed. I have changed speed and temp conditions and it doesn't affect whether it runs or not. I added Serial.print() to see if condition was being tested and it appears to work, but motor still doesn't behave as expected:
MAX6675 warmup
#1= 21.00
Butterzone - OFF
#1= 20.75
Butterzone - OFF
#1= 29.25
Hot - CW
#1= 28.75
Hot - CW
#1= 28.00
Hot - CW
#1= 27.25
Butterzone - OFF
/* Functions defined:
setupArdumoto() -- Setup the Ardumoto Shield pins
driveArdumoto([motor], [direction], [speed]) -- Drive [motor]
(0 for A, 1 for B) in [direction] (0 or 1) at a [speed]
between 0 and 255. It will spin until told to stop.
stopArdumoto([motor]) -- Stop driving [motor] (0 or 1).
setupArdumoto() is called in the setup().
*/
//Thermocouple reads temperature and reports it to LCD
//and serial
#include "max6675.h" //thermocouple library
#include "Wire.h" //LCD screen library
//#include "LiquidCrystal.h" //LCD screen library
#include "Adafruit_LiquidCrystal.h"
#include <SD.h> // SD card library
int DO = 22;
int CS = 23;
int CLK = 24;
MAX6675 thermocouple(CLK, CS, DO);
int CS1 = 3;
float tempA = 0;
float tempA1 = 0;
float tempMin = 20;
float tempMax = 28;
int serialTab = 0;
//identify LCD screen address
Adafruit_LiquidCrystal lcd(0);
// make a degree symbol
uint8_t degree[8] = {140,146,146,140,128,128,128,128};
// Clockwise and counter-clockwise definitions.
// Depending on how you wired your motors, you may need to swap.
#define CW 0
#define CCW 1
// Motor definitions to make life easier:
#define MOTOR_A 0
#define MOTOR_B 1
// Pin Assignments //
// Don't change these! These pins are statically defined by shield layout
const byte PWMA = 3; // PWM control (speed) for motor A
const byte PWMB = 11; // PWM control (speed) for motor B
const byte DIRA = 12; // Direction control for motor A
const byte DIRB = 13; // Direction control for motor B
void setup()
{
setupArdumoto(); // Set all pins as outputs
//start computer communications
Serial.begin(9600);
// start thermocouple communications
pinMode(CS1, OUTPUT);
Serial.println("MAX6675 warmup\n");
digitalWrite(CS1, HIGH);
delay(500);
digitalWrite(CS1, LOW);
delay(500);
// get LCD screen going
lcd.begin(16, 2);
lcd.createChar(0, degree);
// Print a message to the LCD.
lcd.setCursor(0, 0);
lcd.print("please wait");
delay (1000);
lcd.setCursor(0, 1);
lcd.print("checking things");
delay (1000);
lcd.clear();
}
void loop()
{
// read temperatures
digitalWrite(CS1, HIGH);
// read temp delay in ms
delay(2000);
tempA = thermocouple.readCelsius();
digitalWrite(CS1, LOW);
tempA1 = tempA - 3.5;
// print results to computer
Serial.print("#1= ");
Serial.print(tempA1);
// results in single column
Serial.print("\n");
// print results to LCD screen
lcd.setCursor(0, 0);
lcd.print("Temp = ");
lcd.print(tempA1);
lcd.print("C");
//run motors based on temp condition
if(tempA1 <= tempMin)
{
driveArdumoto(MOTOR_A, CCW, 75); // Set motor A to CCW
Serial.print("Cold - CCW");
Serial.print("\n");
}
if(tempA1 >= tempMax)
{
driveArdumoto(MOTOR_A, CW, 75); // Set motor A to CW
Serial.print("Hot - CW");
Serial.print("\n");
}
if((tempA1 > tempMin) && (tempA1 < tempMax))
{
stopArdumoto(MOTOR_A); // STOP motor A
Serial.print("Butterzone - OFF");
Serial.print("\n");
}
/*
// Drive motor B (and only motor B) at various speeds, then stop.
driveArdumoto(MOTOR_B, CCW, 255); // Set motor B to CCW at max
delay(1000); // Motor B will spin as set for 1 second
driveArdumoto(MOTOR_B, CW, 127); // Set motor B to CW at half
delay(1000); // Motor B will keep trucking for 1 second
stopArdumoto(MOTOR_B); // STOP motor B
// Now spin both!
driveArdumoto(MOTOR_A, CW, 255); // Motor A at max speed.
driveArdumoto(MOTOR_B, CW, 255); // Motor B at max speed.
delay(1000); // Drive forward for a second
// Now go backwards at half that speed:
driveArdumoto(MOTOR_A, CCW, 127); // Motor A at max speed.
driveArdumoto(MOTOR_B, CCW, 127); // Motor B at max speed.
*/
}
// driveArdumoto drives 'motor' in 'dir' direction at 'spd' speed
void driveArdumoto(byte motor, byte dir, byte spd)
{
if (motor == MOTOR_A)
{
digitalWrite(DIRA, dir);
analogWrite(PWMA, spd);
}
else if (motor == MOTOR_B)
{
digitalWrite(DIRB, dir);
analogWrite(PWMB, spd);
}
}
// stopArdumoto makes a motor stop
void stopArdumoto(byte motor)
{
driveArdumoto(motor, 0, 0);
}
// setupArdumoto initialize all pins
void setupArdumoto()
{
// All pins should be setup as outputs:
pinMode(PWMA, OUTPUT);
pinMode(PWMB, OUTPUT);
pinMode(DIRA, OUTPUT);
pinMode(DIRB, OUTPUT);
// Initialize all pins as low:
digitalWrite(PWMA, LOW);
digitalWrite(PWMB, LOW);
digitalWrite(DIRA, LOW);
digitalWrite(DIRB, LOW);
}
