Obstacle Avoiding Robot using PIC Microcontroller

The Obstacle Avoiding Robot is an autonomous navigation system orchestrated by the PIC16F877A microcontroller. At the core of the perception system are two infrared (IR) sensors and an HC-SR04 ultrasonic sensor, which continuously monitor the environment for physical barriers. The HC-SR04 uses high-frequency sound waves to measure distance, while the IR sensors detect close-range reflections from nearby objects. The microcontroller reads these sensor inputs to evaluate real-time spatial conditions. When the path is clear, the control unit commands the dual DC gear motors to move forward by sending appropriate logic signals to the L293D motor driver. Because microcontrollers output low-current control signals that cannot directly drive heavy inductive loads, the L293D acts as an essential bridge, using an external power bank or 9V/12V battery to supply the high current needed to actuate the DC gear motors. Upon detecting an obstacle within a predefined threshold, the PIC16F877A processes the data, halts forward movement, executes a programmed avoidance maneuver—such as reversing or turning—by changing the motor rotation directions through the L293D, and then resumes scanning for a clear path. The entire firmware logic is compiled using the MPLAB XC8 Compiler and flashed onto the microcontroller.