irobot.pptx
DESCRIPTION
Manual For line follower robotTRANSCRIPT
Sensors
• A sensor is a device which measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument.
• They are used to provide feedback from the external environment
WORKING OF IR SENSORSThe infrared phototransistor acts as a transistor with the base voltage determined by the amount of light hitting the transistor.
Hence it acts as a variable current source. Greater amount of IR light cause greater currents to flow through the collector-emitter leads.
As shown in the diagram below, the phototransistor is wired in a similar configuration to the voltage divider.The variable current traveling through the resistor causes a voltage drop in the pull-up resistor.This voltage is measured as the output of the device
IR reflectance sensors contain a matched infrared transmitter and infrared receiver pair.These devices work by measuring the amount of light that is reflected into the receiver.Because the receiver also responds to ambient light, the device works best when well shielded from abient light,and when the distance between the sensor and the reflective surface is small(less than 5mm).IR reflectance sensors are often used to detect white and black surfaces. White surfaces generally reflect well,while black surfaces reflect poorly. One of such applications is the line follower of a robot.
IR Sensor Pair
Transmitter (Tx)
Receiver (Rx)
IR sensor PairObject / Line
Transmitter = LED( Light Emitting Diode)
Receiver = Photodiode
The resistance of the sensor decreases when IR light falls on it. A good sensor will have near zero resistancein presence of light and a very large resistance in absence of light.
Principle of Operation
R1< R2
WHITE surfaceMaximum reflectionT1 is turned ONVout is LOW
BLACK surfaceMinimum or No ReflectionT1 is turned OFFVout is HIGH
Interfacing IR sensor with ATmega16
ATMEGA
PORTA
Out: 1
Out: 0
In
10
2
Programming IR sensor with ATmega16
#include <mega16.h>
void main(){
int x;
DDRA=0b00000011; // last two pins as o/p for Vcc & GNDPORTA.0 =1; // VccPORTA.1= 0; // Gnd
x= PINA.2;
// now you can use x for any calculation u want}
COMPARATOR
Registers used in the ADCADMUX – ADC Multiplexer Selection RegisterADCSRA – ADC Control and Status Register A
These registers are used to configure ADCHowever when using CVAVR this will be done by code wizard
Configuring ADC using Code Wizard
1. Open a new project2. Select ‘yes’ to use code wizard3. Goto ADC tab on Code Wizard
ADC
Line Follower : Design
The bot has two IR sensors facing downwards (towards the floor).
The separation between the sensors is such that in normal (correct) position of the bot , both the sensors are on white surface. ie separation > strip width
The bot is driven by two wheel differential drive ie the two back wheels are driven by independent motors.
SleftSright
Line Follower : Algo
When the bot is in correct pos, both sensors are on white & read LOW. The robot should move forward in this case.
Sleft Sright Movement
LOW LOW Forward
SleftSright
Line Follower : Algo
When the bot is over line from right side, left sensor is on white & reads LOW whereas right sensor is on black & reads HIGH The robot should take a right turn in this case to come back in correct pos.
Sleft Sright Movement
LOW HIGH Right Turn
SleftSright
Line Follower : Algo
When the bot is over line from left side, right sensor is on white & reads LOW whereas left sensor is on black & reads HIGH The robot should take a left turn in this case to come back in correct pos.
Sleft Sright Movement
HIGH LOW Left Turn
Sleft
Sright
Line Follower
Sleft Sright Movement Left Motor Right Motor
LOW LOW Forward Forward Forward
LOW HIGH Right Turn Forward Back
HIGH LOW Left Turn Back Forward
IN THIS WHEN VOLTAGE V > 2.5 OUTPUT IS 1 AND IF V < 2.5 OUTPUT IS 0.
ContactsName Contact Email
Nikhil Gupta 9795359594,9044059843 [email protected]
Manish Singhal 9450150792 [email protected]
Rishabh Tekriwal 8960976256 [email protected]
Tanmay Agarwal 8573900881,8009607882 [email protected]
Deepak Kumar 8565997407 [email protected]
Gaurav Mishra 8303340071 [email protected]
Prabha Shankar lahariya 8004274085 [email protected]
Rishabh Yadav 9044172285 [email protected]
Vijay Singh 9044612364 [email protected]
Harshit Gupta 7860495316 [email protected]