replaced some vars by define statements

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

Taupunkt/Taupunkt.ino

@@ -1,24 +1,40 @@
-// include the library code:
+// load library for display
 #include <LiquidCrystal.h>
+// load library for DHT22 sensor
 #include <DHT22.h>
 
-int pinDHT22a = 7;
-DHT22 dht22a(pinDHT22a);
-int status1 = 0;
+#define TRESHOLD   2
+#define HYSTERESIS 1   
+#define MIN_OUT_TEMP 5 // °C
 
-int pinDHT22b = 6;
-DHT22 dht22b(pinDHT22b);
-int status2 = 0;
-const int rs = 13, en = 12, d4 = 11, d5 = 10, d6 = 9, d7 = 8;
-LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
+#define RELAY_PIN 5
 
-float temp1 = 0, temp2 = 0, humi1 = 0, humi2 = 0;
-float treshold = 2;
-float hyster = 1;
-float min_temp = 5;
+#define DHT22_OUTSIDE_PIN 6
+#define DHT22_INSIDE_PIN 7
 
-int relay = 5;
+#define LCD_D7_PIN  8
+#define LCD_D6_PIN  9
+#define LCD_D5_PIN 10
+#define LCD_D4_PIN 11
+#define LCD_EN_PIN 12
+#define LCD_RS_PIN 13
 
+
+// create objects for sensor communication
+DHT22 dht22inside(DHT22_INSIDE_PIN);
+DHT22 dht22outside(DHT22_OUTSIDE_PIN);
+
+// create object for LCD communication
+LiquidCrystal lcd(LCD_RS_PIN, LCD_EN_PIN, LCD_D4_PIN, LCD_D5_PIN, LCD_D6_PIN, LCD_D7_PIN);
+
+// these variables are used to capture error states of the sensors:
+int inside_state = 0;
+int outside_state = 0;
+
+// these variables hold measures from the sensors
+float inside_temp = 0, outside_temp = 0, inside_humi = 0, outside_humi = 0;
+
+// these arrays are used to create some special characters for the LCD
 byte degree[8] = {
   0b00010,
   0b00101,
@@ -65,15 +81,14 @@ byte off[8] = {
 
 
 void setup() {
-  // set up the LCD's number of columns and rows:
+  // set up the LCD
   lcd.begin(16, 4);
   lcd.createChar(0, degree); 
   lcd.createChar(1, tau); 
   lcd.createChar(2, on); 
   lcd.createChar(3, off); 
-  pinMode(relay,OUTPUT);
-  pinMode(4,OUTPUT);
-  digitalWrite(4,LOW);
+
+  // prepare "table" on LCD
   lcd.setCursor(0,0);
   lcd.print("     IN   OUT");
   
@@ -91,6 +106,14 @@ void setup() {
   lcd.print("   .    . ");
   lcd.write((int)0);
   lcd.print("C");
+
+
+  // set up the relay
+  pinMode(RELAY_PIN,OUTPUT);
+
+  // TODO: is this needed any longer?
+  pinMode(4,OUTPUT);
+  digitalWrite(4,LOW);
 }
 
 void printVal(float v){
@@ -101,13 +124,13 @@ void printVal(float v){
 void relayOff(){
   lcd.setCursor(0,0);
   lcd.print("OFF");
-  digitalWrite(relay,LOW);
+  digitalWrite(RELAY_PIN,LOW);
 }
 
 void relayOn(){
   lcd.setCursor(0,0);
   lcd.print("ON ");
-  digitalWrite(relay,HIGH);
+  digitalWrite(RELAY_PIN,HIGH);
 }
 
 void fehler(int col, int code){
@@ -147,84 +170,84 @@ float taupunkt(float t, float r) {
 }
 
 void loop() {  
-  delay(2500);  
-  temp1  = dht22a.getTemperature();
-  humi1  = dht22a.getHumidity();
-  status1 = dht22a.getLastError();
-  temp2  = dht22b.getTemperature();
-  humi2  = dht22b.getHumidity();
-  status2 = dht22b.getLastError();
+  delay(2500); // dht 22 sensor may only be read every two seconds
+  inside_temp  = dht22inside.getTemperature();
+  inside_humi  = dht22inside.getHumidity();
+  inside_state = dht22inside.getLastError();
+  outside_temp  = dht22outside.getTemperature();
+  outside_humi  = dht22outside.getHumidity();
+  outside_state = dht22outside.getLastError();
   
-  boolean err1 = false;
-  boolean err2 = false;
-  if (status1 != dht22a.OK || isnan(temp1)||isnan(humi1)) {    
-    fehler(5,status1);
-    err1 = true;
+  boolean inside_error = false, outside_error = false;
+  
+  if (inside_state != dht22inside.OK || isnan(inside_temp)||isnan(inside_humi)) {    
+    fehler(5,inside_state);
+    inside_error = true;
   } else {    
-    if (temp1<-40 || temp1>80){
+    if (inside_temp<-40 || inside_temp>80){
       lcd.setCursor(5,1);    
-      lcd.print("oor!");
-      err1 = true;
+      lcd.print("OOR!"); // out of range!
+      inside_error = true;
     } else {
       lcd.setCursor(5,1);    
-      printVal(temp1);      
+      printVal(inside_temp);      
     }
-    if (humi1<0 || humi1>100){
+    if (inside_humi<0 || inside_humi>100){
       lcd.setCursor(5,2);    
-      lcd.print("oor!");
-      err1 = true;
+      lcd.print("OOR!"); // out of range
+      inside_error = true;
     } else {
       lcd.setCursor(5,2);
-      printVal(humi1);
+      printVal(inside_humi);
     }
   }
 
-  if (status2 != dht22b.OK) {    
-    fehler(10,status2);
-    err2 = true;
+  if (outside_state != dht22outside.OK) {    
+    fehler(10,outside_state);
+    outside_error = true;
   } else {    
-    if (temp2<-40 || temp2>80){
+    if (outside_temp<-40 || outside_temp>80){
       lcd.setCursor(10,1);    
-      lcd.print("oor!");
-      err2 = true;
+      lcd.print("OOR!"); // out of range!
+      outside_error = true;
     } else {
       lcd.setCursor(10,1);    
-      printVal(temp2);      
+      printVal(outside_temp);      
     }
-    if (humi2<0 || humi2>100){
+    if (outside_humi<0 || outside_humi>100){
       lcd.setCursor(10,2);    
-      lcd.print("oor!");
-      err2 = true;
+      lcd.print("ORR!"); // out of range!
+      outside_error = true;
     } else {
       lcd.setCursor(10,2);
-      printVal(humi2);
+      printVal(outside_humi);
     }
   }  
 
   lcd.setCursor(5,3);    
-  float tau1, tau2;
-  if (err1){
+  float tau_outside, tau_inside;
+  if (inside_error){
     lcd.print("----");
   } else {
-    tau1 = taupunkt(temp1,humi1);    
-    printVal(tau1);
+    tau_inside = taupunkt(inside_temp,inside_humi);    
+    printVal(tau_inside);
   }
 
   lcd.setCursor(10,3); 
-  if (err2){
+  if (outside_error){
     lcd.print("----");
   } else {
-    tau2 = taupunkt(temp2,humi2);    
-    printVal(tau2);    
+    tau_outside = taupunkt(outside_temp,outside_humi);    
+    printVal(tau_outside);    
   }  
 
-  if (err1 || err2){
+  if (inside_error || outside_error || outside_temp < MIN_OUT_TEMP){
     relayOff();
   } else {
-    if (tau1 > tau2 + treshold + hyster) {
+    if (tau_inside > tau_outside + TRESHOLD + HYSTERESIS) {
       relayOn();
     } 
-    if (tau1 < tau2 + treshold) {
+    if (tau_inside < tau_outside + TRESHOLD) {
       relayOff();
     }
   }