Integrating Robots as a System

The LED will glow in this circuit at Tinkercad.

Explanation
In the given circuit, the 9 V battery is connected to the breadboard such that one rail acts as the positive terminal and the other rail acts as the negative terminal. The LED is connected in series with a resistor between these two rails. Therefore, a closed circuit is formed:

Battery (+) → Resistor → LED → Battery (–)

Since the circuit is complete, current flows through the LED in forward bias, so the LED glows. The resistor is used to limit the current and protect the LED from damage.

Apart from DC motors, other motors available in Tinkercad that can be used to design a wheeled robot include servo motors and stepper motors, which can also be used for controlling motion in robotic systems.

On an Arduino Uno, the pins used to connect external components are mainly input and output pins.

• Input pins take signals into the Arduino from devices like sensors, switches, and buttons.
• Output pins send signals from the Arduino to devices like LEDs, buzzers, and motor drivers (as HIGH = 5V or LOW = 0V).
  The Arduino Uno has digital I/O pins (D0–D13) and analog input pins (A0–A5). Some digital pins also provide PWM output for speed/brightness control.

Pin Table (Arduino Uno)

Power pins like 5V, 3.3V, GND, Vin are not I/O pins; they are used only for power connections.

True

Reason — A breadboard is used to connect multiple components and manage multiple connections in a circuit, as it provides several internally connected points for making circuit connections easily.

True

Reason — DC motors act as actuators in a robot and are used to move the wheels of the robot.

False

Reason — In general, the black terminal of a DC motor is connected to the ground of the microcontroller, while the other terminal is connected to the output of the motor driver.

True

Reason — The controller generates all the controlling signals of the robot through a program and controls the working of all components, hence, it is considered the brain of the robot.

True

Reason — A motor can rotate as long as it gets a suitable power supply, so a motor driver is not strictly mandatory just to make the motor run. However, a motor driver acts as an interface between the controller (Arduino) and the motors, helps in controlling the motor, and provides enhanced current capacity because directly connecting a motor to the Arduino can damage the Arduino or reduce motor performance.

True

Reason — The motor driver acts as an interface between the controller (Arduino Uno) and the motors. It is connected in between them to control motor movement and to supply the required current to the motors based on the signals received from the controller.

False

Reason — Arduino Uno has both input and output pins.

False

Reason — In forward mode, all the wheels of the robot should be in motion. Therefore, HIGH values are sent to all four output pins of the Arduino so that all four motors run together and the robot moves forward.

Microcontroller

Reason — Arduino Uno is a microcontroller that acts as the controller or brain of the robot.

Connecting device

Reason — A breadboard is used to connect multiple components in a circuit and provides several internally connected points, making it easier to manage and organise circuit connections.

5V

Reason — HIGH indicates that the motor driver will receive 5V, and the same value will be transferred to the motor with enhanced current capacity.

Actuator

Reason — Motors are the actuators of the robot. They are used to move the wheels of the robot.

GND Pins

Reason — The GND pin is used to give ground connections to the motors that control the wheels of the robot and is also connected to the ground pins of the motor driver IC.

16

Reason — The motor driver IC L293D has 16 pins.

Give input to Arduino

Reason — The digitalWrite() function is used to send input to the Arduino by writing HIGH or LOW values to the digital output pins.

To enable its working

Reason — Without enabling the enable pins, the motor driver will not work. Therefore, the role of the enable pin in the motor driver IC is to enable its working.

1. Motors are used to move the wheels of the robot.
2. Motor Driver L293D has four input pins.
3. 5V pin in Arduino is used to provide a power supply of 5V to other components.
4. Delay function takes input in milli seconds.
5. In forward mode, all the output pins receive high values.

The Tinkercad connection to glow an LED with the help of the battery is shown below:

The value of resistor is 350 Ω

The digitalWrite() function is used to control the state of a digital pin on the Arduino microcontroller. It is used to send a HIGH or LOW signal through an output pin.

• HIGH means the pin outputs 5 V (ON)
• LOW means the pin outputs 0 V (OFF)

Syntax:
digitalWrite(pin, value);
Where pin = digital pin number, and value = HIGH or LOW.

Example:
digitalWrite(3, HIGH);
will send a HIGH signal through pin 3

A breadboard is a device used to connect multiple components in a circuit. It provides multiple connection points that are internally connected. In a breadboard, the first two and the last two lines are horizontally connected, while in the remaining two blocks, the connections are vertically connected. These internal connections help in making circuit connections easily without soldering.

Labeled pin out diagram of motor driver is shown below:

In the forward move of a wheeled robot, all the wheels of the robot should be in motion. For this purpose, a HIGH value is sent to all four output pins (3, 5, 6, and 9) of the Arduino Uno. When HIGH is sent, the motor driver receives 5V, and the same value is transferred to the motors with enhanced current capacity. As a result, all four motors turn on, and the robot moves in the forward direction. The code for move forward is given below:

void move_forward ()
{
    digitalWrite(3, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(6, HIGH);
    digitalWrite(9, HIGH);
}

Left Move:

To give left movement to the robot, its right wheels should be stopped, and left wheels should be in motion. For this purpose, LOW values are sent to pins 3 and 5, and HIGH values are sent to pins 6 and 9 using the digitalWrite() function. As a result, the right-side wheels stop moving, and only the left-side wheels move, giving the robot a left-hand move. The code for left turn is given below:

void turn_left()
{
    digitalWrite(3, LOW);
    digitalWrite(5, LOW);
    digitalWrite(6, HIGH);
    digitalWrite(9, HIGH);
}

Right Move:

To give right movement to the robot, its left wheels should be stopped, and right wheels should be in motion. For this purpose, HIGH values are sent to pins 3 and 5, and LOW values are sent to pins 6 and 9. Consequently, the left-side wheels stop, and only the right-side wheels move, giving the robot a right-hand move. The code for right turn is given below:

void turn_right()
{
    digitalWrite(3, HIGH);
    digitalWrite(5, HIGH);
    digitalWrite(6, LOW);
    digitalWrite(9, LOW);
}