/* Obstacle Avoiding Robot Uses HC-SR04 Ultrasonic Sensor Author: Study For Next */ #include <NewPing.h> #define TRIG_PIN A0 #define ECHO_PIN A1 #define MAX_DISTANCE 200 NewPing sonar(TRIG_PIN, ECHO_PIN, MAX_DISTANCE); // Motor Pins int LM1 = 3; int LM2 = 4; int RM1 = 5; int RM2 = 6; void setup() { pinMode(LM1, OUTPUT); pinMode(LM2, OUTPUT); pinMode(RM1, OUTPUT); pinMode(RM2, OUTPUT); } void loop() { int distance = sonar.ping_cm(); if (distance > 0 && distance < 20) { stop(); delay(500); moveBackward(); delay(500); turnLeft(); delay(1000); } else { moveForward(); } } void moveForward() { digitalWrite(LM1, HIGH); digitalWrite(LM2, LOW); digitalWrite(RM1, HIGH); digitalWrite(RM2, LOW); } // ... other functions (backward, turn, stop)