The ATmega8535 line follower robot uses 8 pieces of proximity sensor module. The sensor module use photodioda for detecting the reflection of light from the line/floor.

Proximity / Line Detector circuit:

ATmega8535 is a low cost and great microcontroller for your robot. This microcontroller is very easy to use, very easy to find, very easy to program. In this tutorial, we used C programming language.

Microcontroller ATmega8535 circuit:

The motor driver L298 able to control the motor with current output up to 2A for single DC motor. For double DC motors, there should be up to 1A for each output channel. This motor driver is very good for small and medium DC motor. L298 is great motor driver for small and medium size or robot such as line follower robot and fire fighter robot.

Motor Driver circuit with L298:

Download the complete ATmega8535 line follower robot tutorial which contains schematic diagram, robot design and source code in PDF version (Indonesian language):

Line Tracker Robot AVR ATmega8535

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IR sensor schematic diagram:

The robot uses IR sensors to sense the line, an array of 8 IR LEDs (Tx) and sensors (Rx), facing the ground has been used in this setup. The output of the sensors is an analog signal which depends on the amount of light reflected back, this analog signal is given to the comparator to produce 0s and 1s which are then fed to the uC

Mainboard (microcontroller + DC motor driver schematic diagram):

The L298 Motor Driver has 4 inputs to control the motion of the motors and two enable inputs which are used for switching the motors on and off. To control the speed of the motors a PWM waveform with variable duty cycle is applied to the enable pins. Rapidly switching the voltage between Vs and GND gives an effective voltage between Vs and GND whose value depends on the duty cycle of PWM. 100% duty cycle corresponds to voltage equal to Vs, 50 % corresponds to 0.5Vs and so on. The 1N4004 diodes are used to prevent back EMF of the motors from disturbing the remaining circuit. Many circuits use L293D for motor control, I chose L298 as it has current capacity of 2A per channel @ 45V compared to 0.6 A @ 36 V of a L293D. L293Dâ€s package is not suitable for attaching a good heat sink, practically you canâ€t use it above 16V without frying it. L298 on the other hand works happily at 16V without a heat sink, though it is always better to use one.

Download the document of ATmega16 line follower robot tutorial for complete tutorial including the working explanation of circuit and program, source code and schematic diagram.

Line Following Robot Tutorial ATMega16

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