Fix discontinuity issues, add comments

precipitationctl.ino

@@ -20,14 +20,21 @@ double blend = 0.0f;
 
 Ticker ticker;
 
-double lerp(double a, double b, double t) {
-  t = max(0.0, min(1.0, t));
-  return a + t * (b - a);
+unsigned long current_time, last_target_time;
+
+/// Linear Interpolation between a and b 
+double lerp(double a, double b, double blend) {
+  // Clamp blend to 0.0 and 1.0
+  blend = max(0.0, min(1.0, blend));
+  // Return blended values
+  return a + blend * (b - a);
 }
 
+
+// Normalized Servo function
 void setServoNormalized(double pos) {
   pos = min(1.0, max(0.0, pos));
-  // 
+  // SQRT to emphasize small values
   pos = sqrt(pos);
   int span = abs(SERVO_MAX - SERVO_MIN);
   int servo_pos = SERVO_MIN + span * pos;
@@ -35,6 +42,7 @@ void setServoNormalized(double pos) {
   // Serial.print(pos);
   // Serial.print(" --> ");
   // Serial.println(servo_pos);
+
   Serial.print(SERVO_MIN); // To freeze the lower limit
   Serial.print(" ");
   Serial.print(SERVO_MAX); // To freeze the upper limit
@@ -43,15 +51,26 @@ void setServoNormalized(double pos) {
   servo.write(servo_pos);
 }
 
+
+// Function to select a new target from the list
 void setNewTarget() {
+  // Store time since power up (milliseconds)
+  last_target_time = millis();
+
+  // Store the previous target
   ptarget = target;
+
+  // Select a new target from the data array (see data.h)
   target = data[data_index];
+
+  // Set a new current value
   current = target;
   // Serial.print("New Target is [");
   // Serial.print(data_index);
   // Serial.print("]: ");
   // Serial.print(target);
 
+  // Increment data_index (count up +1)
   data_index++;
 
   // Reset index when longer than the data (loop over)
@@ -61,8 +80,7 @@ void setNewTarget() {
   }
 }
 
-float testval = 0.0f;
-float increment = 0.01f;
+
 
 void setup() {
   Serial.begin(115200);
@@ -73,6 +91,8 @@ void setup() {
 	ESP32PWM::allocateTimer(2);
 	ESP32PWM::allocateTimer(3);
   
+
+  // Servo setup
   servo.setPeriodHertz(50);// Standard 50hz servo
   servo.attach(servoPin, 1000, 2000);   // attaches the servo on pin 18 to the servo object
                                          // using SG90 servo min/max of 500us and 2400us
@@ -80,24 +100,26 @@ void setup() {
                                          // which are the defaults, so this line could be
                                          // "myservo.attach(servoPin);"
 
-  // Set new Target every 28.44 seconds (leads to 3 days)
+  // Set new Target every INTERVAL seconds (see define statement above)
   ticker.attach(INTERVAL, setNewTarget);  // Interval in seconds
 }
 
+
+// Loop is run forever, repeated
 void loop() {
-  unsigned long currentMillis = millis();
-  blend = fmod(float(currentMillis), (INTERVAL * 1000.0f)) / (INTERVAL * 1000.0f);
+  // Store current time
+  current_time = millis();
+  // Calculate blend value (0.0 directly after new target selected, counts up till 1.0)
+  // (this uses the modulo operation (division remainder) to create a repeating pattern)
+  blend = fmod(
+    float(current_time - last_target_time), 
+    (INTERVAL * 1000.0f)) 
+    / (INTERVAL * 1000.0f);
   current = lerp(ptarget, target, blend);
-  // Serial.print(ptarget);
-  // Serial.print(" (");
-  // Serial.print(int(blend*100));
-  // Serial.print("%) ");
-  // Serial.print(target);
-  // Serial.print(" (");
-  // Serial.print(int((1.0-blend)*100));
-  // Serial.print("%) = ");
-  // Serial.println(current);
 
+  // Set servo position
   setServoNormalized(current);
-  delay(2);
+
+  // Wait for x milliseconds
+  delay(20);
 }