ARDUINO LINE FOLLOWER ROBOT Submitted by:

contents Project overview Block diagram Power supply Arduino IR LED & Photodiode Motor Driver IC Schematic & Working of the project Advantages Applications Future scope Conclusion

Project overview The main objective of the project is sensing a particular path and then following that path a rolling robotic vehicle moves forward. Initially the robot moves on its black track path. Below the robot, IR transmitter present continuously sends IR signals which is reflected through IR receivers which is placed next to the transmitter because of reflections from any non black path. Whenever any side comes on black line, the IR signals are not reflected back from the path and the IR receiver changes its logic state which generates hardware interrupt to microcontroller.

Contd.. The microcontroller, which is interfaced to DC geared motors through motor driver IC acts by stopping one motor so that the direction of the robot moves in such a way to avoid the wrong path till the reflection for both the sensors are resumed. Thus it follows only the black path.

ARDUINO The Arduino microcontroller is an easy to use yet powerful single board computer that has gained considerable traction in the hobby and professional market. The Arduino is open-source, which means hardware is reasonably priced and development software is free.

Image of development board

Features of Duemalinove The Duemalinove board features an Atmel ATmega328 microcontroller operating at 5 V with 2 Kb of RAM, 32 Kb of flash memory for storing programs and 1 Kb of EEPROM for storing parameters. The clock speed is 16 MHz, which translates to about executing about 300,000 lines of C source code per second

…..contd The Arduino programming language is a simplified version of C/C++. If you know C, programming the Arduino will be familiar. If you do not know C, no need to worry as only a few commands are needed to perform useful functions.

Block diagram

Battery An electrical battery is a combination of one or more electrochemical cells, used to convert stored chemical energy into electrical energy. The battery has become a common power source for many household, robotics and industrial applications. Larger batteries provide standby power for telephone exchanges or computer data centers

IR LED Here the IR transmitter is like a normal LED but transmits the IR signals. These are infrared LEDs; the light output is not visible by our eyes. They can be used as replacement LEDs for remote controls, night vision for camcorders, invisible beam sensors, etc.

Photodiode Here the photodiode is like a normal LED but receives the IR signals. A photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation.

MOTOR driver L293D L293D is a dual H-bridge motor driver integrated circuit (IC). Motor drivers act as current amplifiers since they take a low-current control signal and provide a higher-current signal. This higher current signal is used to drive the motors. L293D contains two inbuilt H-bridge driver circuits. In its common mode of operation, two DC motors can be driven simultaneously, both in forward and reverse direction.

Operation of motor driver L293D has 2 set of arrangements where one set has input 1, input 2, output 1 and output 2 and other set has input 3, input 4, output 3 and output 4, according to block diagram if pin no 2 & 7 are high then pin no 3 & 6 are also high. If enable 1 and pin number 2 are high leaving pin number 7 as low then the motor rotates in forward direction. If enable 2 and pin number 10 are high leaving pin number 15 as low then the motor rotates in forward direction.

Contd.. If enable 1 and pin number 2 are low leaving pin number 7 as high then the motor rotates in reverse direction. If enable 2 and pin number 15 are high leaving pin number 10 as low then the motor rotates in forward direction.

Working of project The microcontroller 2 inputs are driven by n-p-n transistors and the base of the transistor is fed from the reversed biased series resistor protected photodiode. The series protection consists of a 10k resistor, a photodiode and a transistor. When no IR light fall on photodiode, the voltage across the photodiode is high then the voltage across the base-emitter of transistor goes low, hence the collector of transistor is high. When IR light falls on photodiode, the voltage across the photodiode decreases, it implies that the voltage across the base emitter of transistor increases hence the collector of transistor is low in this condition.

Contd.. These collectors of Q1& Q2 are fed to pins 1 & 2 of microcontroller. The program is so written that in normal situation motor driver IC gets input from the output of the arduino for both rotating in one direction.