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