Sensors And Micro-Controllers

SCHOOLS OF ROBOTICS .

• Mechanical Design

• Electronics

• Programming

AUTONOMOUS ROBOT

WHAT ARE SENSORS ?

• Any device that converts a change in physical quantity into electrical signals.

TSOP 1738

• It is a Digital IR Sensor.

• Works for IR pulse rate 38 KHz.

• Pulse rate set by microcontroller.

• Accurately distinguish between two colors.

• Outputs – 0 and 5 Volts.

CIRCUIT DIAGRAM

TSOP RANGE INCREASE CIRCUIT

ANALOG IR SENSOR

• Measures amount of reflected IR light

• Outputs in the range of 0V to 5V

• Hence, called Analog Sensor

CIRCUIT DIAGRAM

LIGHT DEPENDENT RESISTOR

• Made of calcium Sulphate

• Act like open circuit in absence of light

• In light, resistance drops from

1 M ohms to10 ohms

• Popularly called LDRs.

7805

• Microcontrollers – 5V

• Motors – 12V

• Converts 8V to 12V into 5V

• Rest lost as heat

• Current Rating - 0.5 A

INTEGRATED CIRCUITS

• Programmable – Simplest form of microcontroller

• Non – Programmable

• E.g. 555, AND gate, OR gate, Mux, Inverters, etc.

MICRO-CONTROLLERS

• A micro controller is the brain of the robot.

• Logic tables relating Input and Output can be defined by you.

• Many other useful features built into the IC itself.

CONFUSED ?

WORKING

• Consists of CPU interfaced with RAM and Flash Memory.

• Flash memory is Programmable

• CPU accesses information from RAM, which gets it from the

flash memory

ATMEGA 16

ATMEGA 8

PROGRAMMING

• Understands only binary language

• Code written in C

• Used to generate a .hex file

• Transfer the .hex file using a programmer

I/O PINS

• DDRX Registers

• PORTX Registers

• PINX Registers

TIMERS

• Timer 0 – 8 bit ( OC0 at PB3)

• Timer 1 – 16 bit ( 2 parts, OC1A at PD5 and OC1B at PD4)

• Timer 2, 8 bit (OC2 at PD7)

• System Clock (fs)

• Timer Clock

THANK YOU