what could be more awsome than building your own robot,today im gonna explain how to build your own obstacle avoiding robot with a servo motor and an ultrasonic sensor.dont worry! I'll guide you step by step through the processes.
so basically ,if you search online ,you will be able to find so many obstacle avoiding robots with different algorithms,in here the algorithm will be,
- robot moves forward
- when detect an obstacle with 35 cm range
look right (40') check for obstacle,if no obstacle is detected turn the ser vo to initial positon ,turn the chassis to right, move forward ,
if obstacle detected in rightside ,look left (130'),if no obstacle turn the servo to initial position turn the chassis left ,move forward in that direction
if obstacle detected in all 3 directions,rotate the robot chassis in 180 degrees and go forward.
now lets see how to build the robot.
Step 1: Finding Components
you will need.
2 wheel robot chassis
l298N motor driver
HC-SR04 ultrasonic sensor
towerpro micro servo 9g
11.1V lipo battery
nuts and bolts,screwdriver
double sided tape
Step 2: Assembling
at this point you should have your 2 wheeled robot chassis on your hand ready to build your robot.assemble the lipo battery,motor driver,arduino, on to the robot chassis.use double sideded tape to fix them onto the chassis .make sure they are properly fixed.
take the micro servo and attach a ultrasonic sensor to a stand like in the picture and attach it to the chassis.
Step 3: L298N Motordriver Connection
attach the Left motor to OUT1 and OUT2
Right motor to OUT3 and OUT4
detach the pin holders in ENA and ENB ,these pins will be use to control the speed of the robot.and let the pin connection be
ENB - 3
connect the lipo battery as shown in the diagram.
if the motors are rotating in the other direction for forward command then simply intechange the motor wires
Step 4: Ultrasonic Sensor Connection
VCC-5V OF ARDUINO
GND-0V OF ARDUINO
this sensor has 4 pins .the trigger pin will emit 8 ultrasonic waves,to trigger the trgger pin we must give a pulse of 10us-1ms with freq 40Hz.
then by equation S=Ut ,distance can be measured here U will be velocity of air 330ms-1 converted to cm per ms and t will be the high period of the echo/2
the connection with arduino will be as the given diagram .
delayMicroseconds(10); digitalWrite(trigpin, LOW);
duration = pulseIn(echo, HIGH); distance = (1 / 29.1) * (duration / 2); delay(60);
Step 5: Servo Motor Connection
red(+)- arduino 5V
orange(signal pin)-9 (ANY PWM PIN)
if given it to rotate at 90 degrees it doesnt mean that it will rotate 90' where the axis was at last..it means that it will rotate to 90 position .(longer flaps will be vetical)
keep in mind that this servomotor can rotate only 0-180 degrees .this is an advatange for us in positional control
if we incoparate PWM with angle 0-255 maps to 0-180 degrees
without using the map operation we can use a built in function
SM.write(90);// the angle you want to rotate
Step 6: Programming
1. Download and Install the Arduino
Desktop IDE · windows - https://www.arduino.cc/en/Guide/Windows ·
Mac OS X - https://www.arduino.cc/en/Guide/MacOSX ·
2. Download and open obstacle_avoid.ino
3. Upload the code to the arduino board via a USB cable
Important !-when given an instance if there are no obstacle within 35 cm range sometimes the programme might execute SM.Write operation part.(since ultrasonic sensor gives dummy Values)to eliminate this problem we have to wait 60ms in else part.
thats it!! now you have a obstacle avoiding robot.