What is a robot?

A robot is a machine that can sense the world around it, think about what it sensed, and act by moving or doing something. If a machine can do all three on its own, we call it a robot.

Think of yourself crossing a road. Your eyes see a car (sense), your brain decides to wait (think), and your legs stay still until the road is clear (act). A robot does the same thing with electronic parts.

The parts of a robot

Human	Robot part	Example
Eyes, ears, skin	Sensors	Camera, distance sensor, touch switch
Brain	Controller	Arduino, Raspberry Pi
Muscles	Actuators	Motors, servos, speakers
Food and energy	Power supply	Batteries
Skeleton	Body (chassis)	Plastic, acrylic or metal frame

Is it a robot?

• A ceiling fan is not a robot: it does not sense anything.
• An automatic door is a simple robot: it senses a person and opens.
• A robot vacuum cleaner is a smarter robot: it senses walls and dirt, plans a path and cleans.

Types of robots you see today

• Industrial robots: robot arms that weld and paint cars in factories.
• Service robots: robot vacuum cleaners, delivery robots, hospital robots.
• Exploration robots: Mars rovers, underwater robots.
• Drones (UAVs): flying robots used for filming, farming and rescue.
• Ground robots (UGVs): rovers used for security, beach cleaning and disaster areas.
• Humanoids: robots shaped like humans.

The word “robot” comes from the Czech word robota, meaning “forced work”. It was first used in a 1920 play by Karel Čapek.

What you will build in this course

Over 11 lessons you will build one robot car and keep making it smarter: first it drives in a square, then it avoids walls, follows a black line, follows the line smoothly using PID control, and finally you drive it from your phone. You will finish with a project of your own.

What you need

Item	Qty	First used in
Arduino Uno (or compatible) and USB cable	1	Lesson 5
Breadboard and jumper wires (male-male, male-female)	1 set	Lesson 2
LEDs, resistors (220 Ω and 10 kΩ), push buttons, buzzer	1 set	Lesson 2
Potentiometer and LDR (light sensor)	1 each	Lesson 3
HC-SR04 ultrasonic distance sensor	1	Lesson 3
IR sensor modules	2 (5 for Lesson 8)	Lesson 3
SG90 servo motor	1	Lesson 4
BO DC gear motors with wheels	2	Lesson 4
L298N motor driver	1	Lesson 4
Robot chassis with caster wheel	1	Lesson 6
2 × 18650 cells with holder (7.4 V) and switch	1	Lesson 6
HC-05 Bluetooth module (or an ESP32 board)	1	Lesson 9

Free software: the Arduino IDE, Tinkercad Circuits (to try circuits online before building them) and a Bluetooth RC controller app on a phone. No kit yet? You can do Lessons 1 to 5 entirely in Tinkercad.

Try it

1. Walk around your home or school and list 5 machines. For each one, write what it senses, how it thinks and how it acts. Decide: robot or not?
2. Draw your dream robot. Label its sensors, controller, actuators and power supply.

Check yourself

1. What are the three things every robot does?
   
   Answer

   It senses, it thinks (decides), and it acts.

2. Which robot part works like our muscles?
   
   Answer

   The actuators, such as motors and servos.

3. Is a washing machine with a water-level sensor a robot? Why?
   
   Answer

   Yes, a simple one. It senses the water level, its controller decides when to stop filling, and it acts by closing a valve and spinning the drum.

Challenge

Find one robot used in India (for example in farming, defence or space) and explain its sense, think and act parts.