Assignment 4: Libraries!

        // Include the CapacitiveSensor library to detect touch 
        #include CapacitiveSensor.h
            
        // Include the Servo library to control a servo motor
        #include Servo.h
            
        // The code below for capacitive sensor and servo motor was taken from Paul Badger
        // and Scott Fitzgerald through the Arduino examples, and then modified for my 
        // own purpose to combine the two functions!
            
        // Create a CapacitiveSensor object named "cs_4_2".
        // The first number (4) is the "send" pin.
        // The second number (2) is the "receive" pin.
        CapacitiveSensor cs_4_2 = CapacitiveSensor(4, 2);
            
            
        // Create a Servo object named "myservo" so we can control it in the code
        Servo myservo;
            
        // Create an integer variable "pos" that will hold the current angle 
        // of the servo (0–180°)
        int pos = 0;
            
            
        // Define a threshold that determines what counts as a "touch".
        // Based on the readings in my Serial Monitor, my conductivity 
        // level reads about ~2k - 3k.
        // With nothing touching the sensor, it reads about ~200.
        // Therefore, I am defining this threshold to be 1k, so that when 
        // my finger touches it will be sure to make the motor move faster
        long touchThreshold = 1000;
            
        
        // Define two different delay times to control how fast the servo moves.
        // "slowSpeed" = delay (in ms) between servo position steps when untouched.
        // "fastSpeed" = delay (in ms) between steps when touched.
        int slowSpeed = 20;
        int fastSpeed = 5;
            
            
        void setup() {
            // Start the Serial Monitor to display sensor value readings.
            Serial.begin(9600);
        
            // Attach the servo’s control wire to Arduino pin 9.
            // This allows the Servo library to send position signals to that pin.
            myservo.attach(9);
        
            // disable auto-calibration of the capacitive sensor.
            // When auto-calibration is off, the sensor’s baseline remains fixed,
            // which can make behavior more stable.
            cs_4_2.set_CS_AutocaL_Millis(0xFFFFFFFF);
        }
            
            
        // main loop 
        void loop() {
            // 1. Read capacitive sensor value
            // This measures the capacitance on the sensor pad by sending 30 pulses.
            // The result is a number: higher means more capacitance (a finger touch).
            // ** ChatGPT helped me understand what this line of code does! 
            long sensorValue = cs_4_2.capacitiveSensor(30);
        
            // 2. Print the sensor reading to the Serial Monitor
            Serial.print("Sensor Value: ");
            Serial.println(sensorValue);
        
            // 3. Decide how fast the servo should move through a variable, delayTime, that
            // holds the current speed setting.
            int delayTime = 0;  
            
            // If the measured capacitance is above the threshold,
            // that means the pad is being touched.
            if (sensorValue > touchThreshold) {
            delayTime = fastSpeed;   // move the servo faster
            } else {
            delayTime = slowSpeed;   // move the servo slower
            }
        
            // 4. Sweep the servo back and forth between 0° and 180°
            // This part is very similar to Scott Fitzgerald's example
            // of 'sweep' for a servo motor. However, I replaced the delay
            // time with my own values so that the motor speeds up or 
            // slows down according to the capacitor.
        
            // Move from 0° up to 180° one degree at a time.
            for (pos = 0; pos <= 180; pos++) {
            myservo.write(pos);   // Tell the servo to move to the "pos" angle
            delay(delayTime);     // Pause briefly before moving to the next degree
            }
        
            // move back from 180° down to 0° one degree at a time.
            for (pos = 180; pos >= 0; pos--) {
            myservo.write(pos);   // Tell the servo to move to the "pos" angle
            delay(delayTime);     // Use the same delay time for this direction
            }
        
            // After this, the loop starts over and repeats forever.
        }