basic sensors for microcontrollers

FULL SETUP

#define encoderPinA 3 // Define pin A for the encoder
#define encoderPinB 4 // Define pin B for the encoder
#define encoderSW 5 // Define pin SW for the encoder (optional)

#define poti_pin A1

int poti_val = 0;
 
volatile int encoderValue = 0; // Variable to store the dial value
volatile int lastEncoded = 0; // Variable to store the last encoded value
 
void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
 
  pinMode(encoderPinA, INPUT); // Set encoder A pin as input
  pinMode(encoderPinB, INPUT); // Set encoder B pin as input
  pinMode(encoderSW, INPUT_PULLUP); // Set encoder SW pin as input with pull-up resistor (optional)
 
  // Attach interrupts to the encoder pins
  attachInterrupt(digitalPinToInterrupt(encoderPinA), updateEncoder, CHANGE);
  attachInterrupt(digitalPinToInterrupt(encoderPinB), updateEncoder, CHANGE);
 
  Serial.println("Encoder Test:");
}
 
void loop() {
  // Print the encoder value
  static int lastPrintValue = -1;
  if (encoderValue != lastPrintValue) {
    Serial.print("Encoder Value: ");
    Serial.println(encoderValue);
    lastPrintValue = encoderValue;
  }
 
  // Check if the encoder button is pressed (optional)
  if (digitalRead(encoderSW) == LOW) {
   

    // read out poti value
    poti_val = analogRead( poti_pin );

     Serial.println("Button Pressed with poti value: ");
     Serial.print (poti_val);

    delay(200); // Debounce delay
  }
}
 
void updateEncoder() {
  int MSB = digitalRead(encoderPinA); // Read the MSB (most significant bit)
  int LSB = digitalRead(encoderPinB); // Read the LSB (least significant bit)
 
  int encoded = (MSB << 1) | LSB; // Combine the two bits to get the encoded value
  int sum = (lastEncoded << 2) | encoded; // Shift last encoded value and combine with current
 
  if (sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue++;
  if (sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue--;
 
  lastEncoded = encoded; // Store the current encoded value for the next change
}

LDR

#define LDRPin A1 // Define the pin where the LDR is connected

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
  pinMode(LDRPin, INPUT); // Set the LDR pin as an input
}

void loop() {
  int ldrValue = analogRead(LDRPin); // Read the analog value from the LDR
  Serial.print("LDR Value: "); // Print the label
  Serial.println(ldrValue); // Print the LDR value
  delay(500); // Wait for half a second before the next reading
}

distance

#define trigPin 13
#define echoPin 12

long duration, distance;
float voltage, speedOfSound = 0.0343; // Speed of sound in cm/us

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  digitalWrite(trigPin, LOW);  
  delayMicroseconds(2);  
  digitalWrite(trigPin, HIGH);
 
  delayMicroseconds(10); // Added this line
  
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration / 2.0) * speedOfSound; // includes Speed of Sound conversion factor into centimeters and microseconds

  Serial.println(distance);
  delayMicroseconds(100); // wait
}

pir sensor

IR distance interruptor

https://wiki.seeedstudio.com/Grove-IR_Distance_Interrupter_v1.2/

void setup()  {
    Serial.begin(9600);
    pinMode(6,INPUT);
}
void loop()  {
    while(1)  {
        delay(500);
        if(digitalRead(6)==LOW)  {
            Serial.println("Somebody is here.");
        }
        else  {
            Serial.println("Nobody.");
        }
    }
}