Aim: The aim of the project is to construct a robot which is built in such a way that that stops its movement or changes its direction when an obstacle is kept in front of it during its movement.
Image of the model:
Working of the project:
IR sensors are used in this project.The sensors emit IR radiations in all the directions and when any obstacle is kept in front of it the IR radiations are reflected back to the sensors which will open the circuit and the power supply to the motors are obstructed due to this.This in turn will stop the movement of the wheels or change the direction of the rotation of the wheels in the direction where the obstacle is not kept.
EAGLE SCHEMATIC CIRCUIT DIAGRAM:
Explanation of the circuit working:
The IC used here is L239D. The output of the IR sensors are connected to the pin numbers 2 and 15 which are the control inputs to the motors. As discussed earlier the sensor emits IR radiations in the forward direction and when an obstacle is sensed the emitted IR radiations are reflected back to the sensor due to which the control input to the motor gets switched off and the movement of the motors in turn the wheels are turned off. A single battery is used to provide power to the L239D.
Working of the IR sensor:
An IR proximity sensor works by applying a voltage to a pair of IR light emitting diodes (LED’s) which in turn, emit infrared light. This light propagates through the air and once it hits an object it is reflected back towards the sensor. If the object is close, the reflected light will be stronger than if the object is further away. The sensing unit (for this experiment a Sharp IS471FE will be used), in the form of an integrated circuit (IC), detects the reflected infrared light, and if its intensity is strong enough, the circuit becomes active. When the sensing unit becomes active, it sends a corresponding signal to the output terminal which can then be used to activate any number of devices. For the purpose of this exercise, a small green LED will turn on when the sensor becomes active.