Obstacle Avoiding Robot (No Microcontroller)

Make an intelligent autonomous robot that avoids obstacles — all without programming or a microcontroller!

This project shows how to build an obstacle avoiding robot using analog electronics, IR sensors, logic circuits, and motor drivers instead of a microcontroller. It’s perfect for beginners, hobbyists, and students who want to understand the fundamentals of robotics and automation.

In this step, the complete circuit for the robot is designed.

The IR sensor modules are used to detect obstacles on the left and right sides. Their outputs are connected to LM358 op-amp comparator circuits, which convert the analog sensor signals into digital logic levels.

These logic signals are then processed using logic gates to determine the robot’s movement direction. The processed signals are fed into the L293D motor driver IC, which controls the rotation of the DC motors.

Before moving to PCB design, the circuit should be verified using simulation or breadboard testing to ensure correct sensor response and motor operation.

After finalizing the circuit, a PCB layout is designed using PCB design software.

All components such as:

1. IR sensor connectors
2. LM358 op-amp
3. Logic gate ICs
4. L293D motor driver
5. Voltage regulator (7805)

are placed carefully to minimize wiring complexity.

Once the layout is completed, the PCB is printed, etched, and cut to the required size. Proper track thickness is maintained for motor current paths.

In this step, all electronic components are mounted and soldered onto the prepared PCB.

Soldering is done in the following order:

1. Resistors and capacitors
2. IC sockets
3. Voltage regulator
4. Motor driver IC
5. Sensor and motor connectors

After soldering, the PCB is inspected for:

1. Short circuits
2. Cold solder joints
3. Proper component orientation

Once the PCB is ready, it is fixed onto the robot enclosure (chassis) using silicon.

Next:

1. DC motors are mounted on the chassis
2. Wheels are attached to the motor shafts
3. IR sensors are fixed at the front of the robot
4. Wiring is routed neatly to avoid interference with moving parts

Proper alignment of sensors and wheels is important for smooth navigation.

In the final step, the power supply is connected using a 12V or 9v rechargeable battery .

After powering ON:

1. The voltage regulator output is checked
2. Sensor operation is tested
3. Motor movement is observed

The robot is then placed on the floor and tested with obstacles to verify:

1. Forward movement
2. Left and right turns
3. Reverse motion when obstacles are detected on both sides

Any required fine-tuning (sensor sensitivity or alignment) is done at this stage.

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This project shows that you don’t need complex programming to build a smart robot. With a few basic electronic components and careful assembly, you can create your own obstacle-avoiding robot and learn the core principles of robotics and automation.

Feel free to modify the design, experiment with sensor placement, or improve the mechanical structure. Try it yourself and take your first step into the exciting world of robotics!