Comment construire un bâton aveugle en utilisant un capteur Arduino Nano et Ultrasonic

https://www.youtube.com/watch?v=B1QHVHFGRDS

/* ========================== Pin Definitions ========================== */
// Ultrasonic Sensor Pins
#define vccPin 4       // Ultrasonic sensor VCC pin
#define trigPin 5      // Ultrasonic sensor Trigger pin
#define echoPin 6      // Ultrasonic sensor Echo pin
#define gndPin 7       // Ultrasonic sensor GND pin
// Output Signal Pins
#define ledPin 9       // LED signal pin
#define buzzerPin 2  // Buzzer signal pin

/* ========================== Ultrasonic Sensor Data ========================== */
long duration = 0;     // Duration of ultrasonic signal bounce-back (in microseconds)
int distance = 0;      // Calculated distance between the object and sensor (in cm)

/* ========================== Timing Variables ========================== */
// Stores the last time LED and Buzzer states were updated
unsigned long previousLedMillis = 0;
unsigned long previousBuzzerMillis = 0;

/* ========================== Multitasking Interval Variables ========================== */
// Determines the interval between LED blinks and buzzer beeps (in milliseconds)
int ledInterval = 0;        // LED blink interval — varies based on object distance
int buzzerInterval = 0;     // Buzzer beep interval — varies based on object distance

/* ========================== State Variables ========================== */
// Tracks the current state of LED and Buzzer
bool ledState = LOW;        // LED state (ON or OFF)
bool buzzerState = LOW;     // Buzzer state (ON or OFF)

/* ========================== Current Time Variable ========================== */
// Holds the current time in milliseconds
unsigned long currentMillis = 0;

/* ========================== Measure Distance ========================== */
/**
* Triggers the ultrasonic sensor and calculates the distance to the nearest object.
*/
void measureDistance() {
 // Send a 10µs pulse to the trigger pin to start the measurement
 digitalWrite(trigPin, LOW);
 delayMicroseconds(2);
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10);
 digitalWrite(trigPin, LOW);
 // Measure the duration of the pulse on the echo pin
 duration = pulseIn(echoPin, HIGH);
 // Calculate the distance in centimeters (speed of sound: 343 m/s)
 distance = (duration / 2) / 29.1;
 // Output the distance measurement to the Serial Monitor
 Serial.print("Distance: ");
 Serial.print(distance);
 Serial.println(" cm");
}

/* ========================== Task: Trigger Buzzer ========================== */
/**
* Controls the buzzer beep rate based on object proximity.
* Buzzer beeps faster when the object is closer.
*/
void task_triggerBuzzer() {
 // Map the distance to a buzzer interval (30ms when close, 100ms when far)
 buzzerInterval = map(distance, 0, 50, 30, 100);
 // Toggle the buzzer state when the interval has passed
 if (currentMillis - previousBuzzerMillis >= buzzerInterval) {
   previousBuzzerMillis = currentMillis;      // Update the last buzzer time
   buzzerState = !buzzerState;                // Toggle the buzzer state
   digitalWrite(buzzerPin, buzzerState);      // Apply the new state to the pin
 }
}

/* ========================== Task: Trigger LED ========================== */
/**
* Controls the LED blink rate based on object proximity.
* LED blinks faster when the object is closer.
*/
void task_triggerLed() {
 // Map the distance to an LED interval (150ms when close, 1000ms when far)
 ledInterval = map(distance, 0, 50, 150, 1000);
 // Toggle the LED state when the interval has passed
 if (currentMillis - previousLedMillis >= ledInterval) {
   previousLedMillis = currentMillis;         // Update the last LED time
   ledState = !ledState;                      // Toggle the LED state
   digitalWrite(ledPin, ledState);            // Apply the new state to the pin
 }
}

/* ========================== Stop Alerts ========================== */
/**
* Deactivates the LED and buzzer when no object is within range.
*/
void stopAlerts() {
 digitalWrite(buzzerPin, LOW);                // Turn off the buzzer
 digitalWrite(ledPin, LOW);                   // Turn off the LED
 ledState = LOW;                              // Reset LED state
 buzzerState = LOW;                           // Reset buzzer state
}

/* ========================== Setup Function ========================== */
/**
* Initializes hardware components, configures I/O pins, and stabilizes the sensor.
*/
void setup() {
 // Configure Ultrasonic Sensor Pins
 pinMode(vccPin, OUTPUT);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 pinMode(gndPin, OUTPUT);
 // Configure Output Signal Pins
 pinMode(ledPin, OUTPUT);
 pinMode(buzzerPin, OUTPUT);
 // Power up the Ultrasonic Sensor
 digitalWrite(vccPin, HIGH);  // Provide 5V power
 digitalWrite(gndPin, LOW);   // Connect GND to 0V
 // Ensure all signals are in their default LOW state
 digitalWrite(ledPin, LOW);
 digitalWrite(buzzerPin, LOW);
 digitalWrite(trigPin, LOW);
 // Initialize Serial Monitor for debugging
 Serial.begin(9600);
 // Stabilize the ultrasonic sensor after powering up
 delay(1000);
}

/* ========================== Main Loop ========================== */
/**
* Continuously checks distance and triggers LED and buzzer alerts based on proximity.
*/
void loop() {
 // Capture the current time in milliseconds
 currentMillis = millis();
 // Measure the distance from the ultrasonic sensor
 measureDistance();
 // Activate LED and buzzer alerts if object is within 30cm range
 if (distance >= 0 && distance <= 50) {
   task_triggerBuzzer();
   task_triggerLed();
 } else {
   // Stop alerts if the object is out of range
   stopAlerts();
 }
}

Retrouvez l’histoire de Raspberry Pi dans cette vidéo :