REPORT ON BASIC ELECTRONICS AND ROBOTICS WORKSHOP

(At College of Engineering, Guindy – on the 10^th and 11^th of January 2009)

(TOPIC: ‘ROBOTICS USING DISCRETE ELECTRONIC COMPONENTS’)

The following is the report on a workshop held at College of Engineering, Guindy on the 10^th and 11^th of January 2009. The workshop was conducted by two R & D employees of a Mumbai based electronics solutions company. The workshop had participants from various technical branches at varying levels – including electronics, Information technology, and Mechanical Engineering, right from 1^st to 4^th years. Besides students from Vishakapatnam, Bengaluru and Tirupati attended the workshop and a total of 20 teams (of twos and threes) participated.

The workshop was aimed at creating a practical approach towards electronics and creating some robots which had basic functionalities – such as sensing sound, light, obstacles, etc and reacting to them in different ways. Many concepts which were dealt with, in regular classes, were brought out alive in the workshop. As students from other branches of Engineering were also present, the instructor took us through the concepts at a slow pace.

THE KIT

The kit contained a collection of resistors and capacitors of different values, transistors, sensors (mic, photodiodes), visible and IR LEDs, a TSOP module, op-amp and 555 timer ICs, a chassis for the robot, a motor driver circuit, two motors and a breadboard which could be mounted on the robot. Also, a multimeter and a manual were supplied with the kit.

SUMMARY of TOPICS COVERED

INTRODUCTION

Robots are human designed machines which perform tasks that may be harder for humans and can be:

-teleoperated(operated from a remote location), or

-manually operated, or

-autonomous(self governing robots)

Teleoperated robots are further classified as wired or wireless. Autonomous robots can be PC controlled (for faster reaction in complex systems), Microcontroller controlled (when no high end calculations are required), or using discrete electronics components (without programming).

BASICS OF ELECTRONICS

THEORY:

The basics were dealt with in this session. The topics covered were – Ohms law, power equation, fixed and variable resistors and their types.

The identification of resistors and variable resistors (from the colour coding, and 3 digit codes) were skills that were put to use later in the workshop. Capacitors, their types (polar and non polar), identification (from 3 digit codes in case of non-polar capacitors) and applications (as timing element, filters and energy storage elements). Theoretical calculations were done to fix current limiting resistors in LED circuits, and potential divider arrangement of the photodiode. Pointers were given to debug circuits.

PRACTICAL:

Glowing LEDs.

TRANSISTORS

THEORY

The various applications of transistors were listed. However, their use in digital circuits is limited to switching. The transistor to be used is mainly decided based on the requirement, and some decisive parameters like V_ce, Ic, DC current gain and Transition frequency. The current limiter resistors, and fixed biasing resistors were fixed through theoretical calculations and data from the datasheet.

PRACTICAL

Transistor as a switch in glowing LEDs.

SENSORS

THEORY

Sensors are an integral part of the robot apart from actuators. The capability and complexity of a robot is directly dependant on the number of sensory inputs.

There are two types of sensors – Proximity/Range sensors and Environmental sensors. Proximity sensors are further classified as mechanical or Reflective. Environmental sensors include light, temperature, pressure, humidity, gases.

IR LEDs, mechanical obstacle sensors, and IR photodiode were studied in detail.

PRACTICAL

The potential divider arrangement of a photodiode, both in light and darkness; light activated robot.

OP-AMPS

THEORY

Operational amplifiers are used to perform various mathematical operations like integration, addition, subtraction, differentiation, etc. The characteristics and their use as a comparator was studied. The advantages and disadvantages of different op-amps were looked into. The dual op-amp LM 358 was used in the following practical work.

The algorithm for line sensor robots (with one and two sensors), two line sensor robots were learnt.

PRACTICAL

Line sensing robot – with one sensor, two sensors;

IC 555

THEORY

The application of the 555 timer was listed – timer, square wave generator, comparator, Schmitt trigger, etc. The various modes were listed, of which the monostable and astable modes and their connections were studied in detail.

The TSOP module was also studied after this topic.

PRACTICAL

Monostable state of LM555 – connection; Astable operation of LM555 – square wave generator, timer; Clap activated robot, obstacle sensing robot using TSOP.

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In addition, several other modifications were suggested in the manual that was provided, resulting in a large number of combinations of robots, making the kit ideal for most competitions.

We were also told about the ‘Micromouse’ competition, which is claimed to be the world’s most advanced robotics competition. We were inspired to develop our skills to that level to make it possible for us to participate in such competitions.

The total cost of the workshop was around Rs.5000 per team, which included the kit. The practical approach to electronics was very refreshing and unique. Indeed, the money spent on the training was worth it. The workshop was both enlightening and entertaining. And we would recommend such workshops to our classmates.

(As compiled on 18th of january, 2009. The workshop was attended with a classmate - Raghavan)