Initial junk to get temp control working.

Totally not working yet, just getting it pushed
to the remote

boil_kettle/boil_kettle.ino

@@ -3,7 +3,7 @@
 #include <SPI.h>
 #include <Ethernet.h>
 
-// Additoinal Libraries
+// Additional Libraries
 #include <ArduinoJson.h>
 #include <MQTT.h>
 #include <LiquidCrystal_I2C.h>
@@ -15,17 +15,28 @@
 #include "config.h"
 #include "button.h"
 #include "slowPWM.h"
+#include "thermoControl.h"
 
 // Global variables.
-byte KettleDuty = 0;
-bool KettleOn = false;
+uint8_t KettleDuty = 0;
+double KettleTemp;
+uint8_t KettleSetpoint;
+modes KettleMode = OFF;
+
+/* Defined in config.h for now */
+// uint8_t ThreshPWR = 5;
+// double Hysteresis = 1;
 
 // User I/O objects.
 Button Enter;
-slowPWM boilPWM;
 MD_REncoder rotary = MD_REncoder(encoderDT, encoderCLK);
 LiquidCrystal_I2C lcd(0x27,20,4);
 
+// Internal I/O
+Adafruit_MAX31865 KettleThermo = Adafruit_MAX31865(10);
+slowPWM boilPWM;
+thermoControl KettleController = thermoControl(&KettleTemp, &KettleSetpoint, &KettleDuty, &ThreshPWR, &Hysteresis);
+
 EthernetClient net;
 MQTTClient mqtt_client;
 
@@ -34,13 +45,26 @@ unsigned long lastRun = 0;
 // Return a character array to represent the
 // On/Off state of the kettle.
 char* KettleState() {
-  if (KettleOn) {
-    return (char*)"On";
+  if (KettleMode == MANUAL) {
+    return (char*)"Manual";
+  } else if (KettleMode == AUTOMATIC) {
+    return (char*)"Auto";
   } else {
     return (char*)"Off";
   }
 }
 
+char* ShowKettleSetting() {
+  char* LCD_Line;
+  if (KettleMode == MANUAL) {
+    return sprintf(LCD_Line, "Kettle Power:   %03d%", KettleDuty);
+  } else if (KettleMode == AUTOMATIC) {
+    return sprintf(LCD_Line, "Kettle Temp:    %03dF", KettleSetpoint);
+  } else {
+    return (char[])"        Off          ";
+  }
+}
+
 // Interrupt function to run when encoder is turned.
 //
 // Increases/decreases the kettle output to a max
@@ -65,7 +89,7 @@ void doEncoder()
 
 // LCD menu setup.
 LiquidLine KettleState_line(0, 0, "Boil Kettle      ", KettleState);
-LiquidLine kettle_power_line(0, 1, "Kettle Power %   ", KettleDuty);
+LiquidLine kettle_power_line(0, 1, ShowKettleSetting);
 LiquidScreen home_screen(KettleState_line, kettle_power_line);
 LiquidMenu menu(lcd);
 
@@ -84,6 +108,7 @@ void setup() {
   pinMode(encoderDT, INPUT_PULLUP);
   Enter.begin(encoderBTN);
   boilPWM.begin(kettlePWM, PeriodPWM);
+  KettleThermo.begin(MAX31865_3WIRE);
 
   // if you get a connection, report back via serial:
   if (Ethernet.linkStatus() == LinkON) {
@@ -106,7 +131,8 @@ void UpdateBoilKettle(){
   static byte last_KettleDuty = 0;
 
   if (Enter.pressed()) {
-    KettleOn = !KettleOn;
+    
+    KettleMode = !KettleMode;
     menu.update();
   }
 
@@ -115,7 +141,8 @@ void UpdateBoilKettle(){
     menu.update();
   }
 
-  if (KettleOn) {
+  if (KettleMode) {
+    KettleController.Compute();
     digitalWrite(kettlePWM, boilPWM.compute(KettleDuty));
   } else {
     digitalWrite(kettlePWM, boilPWM.compute(0));
@@ -123,6 +150,7 @@ void UpdateBoilKettle(){
 }
 
 void loop() {
+  KettleTemp = KettleThermo.readRTD();
   UpdateBoilKettle();
 
   unsigned long elapsedTime = (millis() - lastRun);

boil_kettle/thermoControl.cpp

@@ -0,0 +1,71 @@
+
+#include <Arduino.h>
+#include <EEPROM.h>
+#include "thermoControl.h"
+
+thermoControl::thermoControl(double* input_temp, uint8_t* setpoint_temp, uint8_t* output_pwm, uint8_t* max_threshold, uint8_t* hysteresis) {
+  output_pwm = output_pwm;
+  input_temp = input_temp;
+  setpoint_temp = setpoint_temp;
+  
+  outMax = 100;
+  outMin = 10;
+  
+  OpMode = OFF;
+  SampleTime = 100;
+  lastTime = millis()-SampleTime;
+
+}
+
+bool thermoControl::Compute() {
+  unsigned long now = millis();
+  unsigned long timeChange = (now - lastTime);
+
+  if(timeChange>=SampleTime && OpMode == AUTOMATIC) {
+    double output;
+    double input = *input_temp;
+    double error = (double)*setpoint_temp - input;
+
+    if (error >= (double)*max_threshold) {
+      output = outMax;
+    } else if (error > *hysteresis) {
+      output = 100 * error / *max_threshold;
+      output = max(output, outMin);
+      output = min(output, outMax);
+    } else {
+      output = 0;
+    }
+    *output_pwm = output;
+    lastTime = now;
+
+    return true;
+  } else {
+    return false;
+  }
+}
+
+void thermoControl::SetSampleTime(int NewSampleTime) {
+  if (NewSampleTime > 0) {
+    SampleTime = (unsigned long)NewSampleTime;
+  }
+}
+
+void thermoControl::SetPowerLimits(uint8_t Max, uint8_t Min) {
+  if(Min >= Max) return;
+  outMax = Max;
+  outMin = Min;
+}
+
+void thermoControl::SetMode(modes newMode) {
+  OpMode = newMode;
+}
+
+modes thermoControl::GetMode() {
+  return OpMode;
+}
+
+modes thermoControl::CycleMode() {
+  OpMode = (modes)(OpMode + 1);
+  return OpMode;
+}
+    

boil_kettle/thermoControl.h

@@ -0,0 +1,33 @@
+#ifndef THERMOCONTROL_h
+#define THERMOCONTROL_h
+
+enum modes : uint8_t {OFF, AUTOMATIC, MANUAL};
+
+class thermoControl {
+  private:
+    double *input_temp;
+    double *output_pwm;
+    double *setpoint_temp;
+    double *hysteresis;
+    double *max_threshold;
+    double outMax;
+    double outMin;
+    
+    modes OpMode;
+
+    unsigned long SampleTime;
+    unsigned long lastTime;
+
+  public:
+    thermoControl(double*, uint8_t*, uint8_t*, uint8_t*, uint8_t*);
+    bool Compute();
+    void SetSampleTime(int);
+    void SetPowerLimits(uint8_t, uint8_t);
+    void SetHysteresis(double);
+    void SetThreshPWR(uint8_t);
+    void SetMode(modes);
+    modes GetMode();
+    modes CycleMode();
+};
+
+#endif