Author : Ghibea Ovidiu-Catalin
Group : 1221A
Faculty : FILS
This robot has an anxiety problem and does not want to meet with anyoane or anything.
Small robot that is capable of sensing incoming obstacles and avoid them. Once the switch is turned on, the robot will start moving in a straight line. The ultrasonic sensor placed on the front of the robot will pick up any incoming waves and will translate this into distance in the code. If the received distance will be lower than a certain threshold He will stop and signal to the motor driver module to turn left until there is nothing in front of him anymore, after which he will continue moving.
Components
Name | Quantity |
---|---|
Arduino Uno | 1 |
HC-SR04 Ultrasonic Sensor | 1 |
Speaker | 1 |
LM298N Motor Driver Module | 1 |
5V DC Motors | 2 |
Switch | 1 |
9V Battery | 1 |
Wheels | 2 |
Chassis | 1 |
Jumper Wires | 1 |
Electric diagram:
First define trig and echo pin of HC-SR04 in the program. In this project the trig pin is connected to GPIO9 and echo pin is connected to GPIO10 of Arduino NANO.
int trigPin = 9; // trig pin of HC-SR04 int echoPin = 10; // Echo pin of HC-SR04
Define pins for input of LM298N Motor Driver Module. The LM298N has 4 data input pins used to control the direction of motor connected to it.
int revleft4 = 4; //REVerse motion of Left motor int fwdleft5 = 5; //ForWarD motion of Left motor int revright6 = 6; //REVerse motion of Right motor int fwdright7 = 7; //ForWarD motion of Right motor
In setup() function, define the data direction of utilised GPIO pins. The four Motor pins and Trig pin is set as OUTPUT and Echo Pin is set as Input.
pinMode(revleft4, OUTPUT); // set Motor pins as output pinMode(fwdleft5, OUTPUT); pinMode(revright6, OUTPUT); pinMode(fwdright7, OUTPUT); pinMode(trigPin, OUTPUT); // set trig pin as output pinMode(echoPin, INPUT); //set echo pin as input to capture reflected waves
In loop() function, get the distance from HC-SR04 and based on the distance move the motor direction. The distance will show the object distance coming in front of the robot. The Distance is taken by bursting a beam of ultrasonic up to 10 us and receiving it after 10us. To learn more about measuring distance using Ultrasonic sensor and Arduino, follow the link.
digitalWrite(trigPin, LOW); delayMicroseconds(2); digitalWrite(trigPin, HIGH); // send waves for 10 us delayMicroseconds(10); duration = pulseIn(echoPin, HIGH); // receive reflected waves distance = duration / 58.2; // convert to distance delay(10);
If the distance is greater than the defined distance means there is not obstacle in its path and it will moving in forward direction.
if (distance > 19) { digitalWrite(fwdright7, HIGH); // move forward digitalWrite(revright6, LOW); digitalWrite(fwdleft5, HIGH); digitalWrite(revleft4, LOW); }
If the distance is less than the defined distance to avoid obstacle means there is some obstacle ahead. So in this situation robot will stop for a while and movebackwards after that again stop for a while and then take turn to another direction.
if (distance < 18) { digitalWrite(fwdright7, LOW); //Stop digitalWrite(revright6, LOW); digitalWrite(fwdleft5, LOW); digitalWrite(revleft4, LOW); delay(500); digitalWrite(fwdright7, LOW); //movebackword digitalWrite(revright6, HIGH); digitalWrite(fwdleft5, LOW); digitalWrite(revleft4, HIGH); delay(500); digitalWrite(fwdright7, LOW); //Stop digitalWrite(revright6, LOW); digitalWrite(fwdleft5, LOW); digitalWrite(revleft4, LOW); delay(100); digitalWrite(fwdright7, HIGH); digitalWrite(revright6, LOW); digitalWrite(revleft4, LOW); digitalWrite(fwdleft5, LOW); delay(500); }
This is how a robot can avoid obstacles in its path without getting stuck anywhere.
After finishing the project, I learned that: