Obstacle Avoiding Robot without microcontroller


An obstacle avoiding robot is an intelligent device, which can automatically sense and overcome obstacles on its path. It is developed without micro-controller in order to eliminate critical circuits, difficult programming etc. All you want to do is to just understand the circuit diagram and start doing this robot. This simple technique can be incorporated in wheeled robots to keep them away from damages and accidents.

What’s required?

This intelligent robot requires several components to bring them alive. It doesn’t cost too much, and easily available in all electronics markets as well.

  • 2 x 12 V DC motor
  • 2 x IR Sensor modules
  • 1 x IC 7404
  • 1 x IC 7805
  • 1 x IC L293D
  • 1 x Breadboard
  • 2 x 10 uf capacitors
  • 2 x Plastic wheels
  • 1 x Castor wheel
  • 1 x Battery (requires according to the usage)
  • 1 x Battery holder
  • 1 x Battery snap
  • 2 meters of Breadboard wires
  • 1 meter of Two-core wires
  • 2 x 2 feet cardboard (for preparing the body of robot)

Circuit Diagram:

How to assemble them?

The circuit diagram of obstacle avoiding robot is shown in the above picture. It could utmost help you to develop this robot with ease. In case, if you are new to robotics, observe the following step by step instructions of all connections given below.

Preparation of outer part:

  • Cut one square-shaped cardboard and paste one lengthy cardboard below it
  • Fix two 12 V DC motors inside the square cardboard in opposite directions
  • Connect two plastic wheels on the shaft of the motors
  • Fix the castor wheel below the lengthy cardboard
  • Place the Right IR Module in top-right of lengthy cardboard, and Left IR Module in top-left of lengthy cardboard.

Breadboard connections:

1)      Power Supply:

  • Take the breadboard and connect the battery holder in horizontal position
  • Insert the positive and negative wire of battery snap in holder
  • Attach IC 7805 Voltage Regulator, and place one 10 uf capacitor in IN and GND connection of IC 7805 and other in GND and OUT connection.
  • Take the positive supply from battery holder via breadboard wire and place it in IN of IC 7805, and also connect its negative supply in last row of breadboard.
  • Place the GND of IC 7805 in last row of breadboard, and transfer its OUT to first row of breadboard.
  • As a result of these connections, +5 V power is obtained in the first row of breadboard

2)      Integrated circuit (IC) connections:

  • Insert IC 7404 and IC L293D in the breadboard
  • Supply +5 V power to 1st, 8th, 9th, and 16th pins of IC L293D, and 14th pin of IC 7404
  • Provide ground connection to 4th, 5th, 12th, and 13th pins of IC L293D, and 7th pin of IC 7404
  • Take a breadboard wire and connect the 10th pin of IC 7404 to 7th pin of IC L293D
  • Similarly, connect 4th pin of IC 7404 to 10th pin of IC L293D

3)      12V DC motor connections:

  • Take the wire of Right Motor and insert it in 3rd & 6th pins of IC L293D
  • Also, place the wire of Left Motor in 11th and 14th pins of IC L293D

4)      IR Sensor Module connections:

  • Give +5V power to IR sensor modules via red-colored wire and ground connection via black-colored wire.
  • Place the mid wire of Right IR Sensor Module in 11th pin of IC 7404 and 2nd pin of IC L293D
  • Connect the mid wire of Left IR Sensor Module in 3rd pin of IC 7404 and 15th pin of IC L293D

How does it work?

After finishing the assembling work, connect the 9V battery via battery snap. Then, see what happens. The robot will automatically start traveling on the unstructured path without hitting any objects.

When the left IR module senses any obstacles on its way, it will turn right till it stops sensing. Similarly, it will turn left when the right IR module senses obstacles. If both the sensors sense an obstacle, then the robot will stop moving.

You can see the working of the Obstacle Avoiding Robot without micro-controller in the below video:


The concept of developing an Obstacle Avoiding Robot may be simple, but you may meet some obstacles in implementing it. Overall, I feel the above details are well-enough to complete this intelligent robot. It will cost approximately $40 U S Dollars to develop one. You can try it in your free time, and any quires related to it are most welcomed.

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