Removed redundant code (DRY principal) and made it more readable.

4 Channel Relay Plant Watering System and code/arduino_Watering4/arduino_Watering4.ino

@@ -1,84 +1,43 @@
-int IN1 = 2;
-int IN2 = 3;
-int IN3 = 4;
-int IN4 = 5;
+const int pumpRelay[4] = { 2, 3, 4, 5 };
+const int moistureSensor[4] = { A0, A1, A2, A3 };
+const int ON = LOW;
+const int OFF = HIGH;
 
-int Pin1 = A0; //模拟引脚A0连接传感器输入
-int Pin2 = A1;
-int Pin3 = A2;
-int Pin4 = A3;
+// Lower = wetter, 275 = completely wet, 600 = completely dry
+const int moistureThreshold[4] = { 400, 400, 400, 400 };  // Adjust to each plant's needs
 
-float value1 = 0;
-float value2 = 0;
-float value3 = 0;
-float value4 = 0;
 void setup() {
   Serial.begin(9600);
-  pinMode(IN1, OUTPUT);
-  pinMode(IN2, OUTPUT);
-  pinMode(IN3, OUTPUT);
-  pinMode(IN4, OUTPUT);
 
-  pinMode(Pin1, INPUT);
-  pinMode(Pin2, INPUT);
-  pinMode(Pin3, INPUT);
-  pinMode(Pin4, INPUT);
+  for(int i = 0; i < 4; i++) {
+    pinMode(pumpRelay[i], OUTPUT);
+    digitalWrite(pumpRelay[i], OFF);  
+    pinMode(moistureSensor[i], INPUT);
+  }
 
-  digitalWrite(IN1, HIGH);
-  digitalWrite(IN2, HIGH);
-  digitalWrite(IN3, HIGH);
-  digitalWrite(IN4, HIGH);
   delay(500);
 }
+
 void loop() {
+  int moistureLevel;  
+
+  for(int i = 0; i < 4; i++) {
+    moistureLevel = analogRead(moistureSensor[i]);
 
-  Serial.print("MOISTURE LEVEL:");
-  value1 = analogRead(Pin1);
-  Serial.println(value1);
-  if(value1>750)
-  {
-      digitalWrite(IN1, LOW);
-  }
-  else
-  {
-    digitalWrite(IN1, HIGH);
-    }
-
-  Serial.print("MOISTURE LEVEL:");
-  value2 = analogRead(Pin2);
-  Serial.println(value2);
-  if(value2>750)
-  {
-      digitalWrite(IN2, LOW);
-  }
-  else
-  {
-    digitalWrite(IN2, HIGH);
-    }
+    Serial.print("MOISTURE LEVEL ");
+    Serial.print(i);
+    Serial.print(": ");
+    Serial.println(moistureLevel);
 
-  Serial.print("MOISTURE LEVEL:");
-  value3 = analogRead(Pin3);
-  Serial.println(value3);
-  if(value3>750)
-  {
-      digitalWrite(IN3, LOW);
-  }
-  else
-  {
-    digitalWrite(IN3, HIGH);
+    // If the soil is too dry, turn the pump on. 
+    // Otherwise, turn the pump off
+    if(moistureLevel > moistureThreshold[i]) {
+      digitalWrite(pumpRelay[i], ON);
+    } else {
+      digitalWrite(pumpRelay[i], OFF);
     }
-
-  Serial.print("MOISTURE LEVEL:");
-  value4 = analogRead(Pin4);
-  Serial.println(value4);
-  if(value4>750)
-  {
-      digitalWrite(IN4, LOW);
   }
-  else
-  {
-    digitalWrite(IN4, HIGH);
-    }
-    Serial.println();
+
+  Serial.println();
   delay(1000);
 }