In this project, we will learn how to drive a simple Toy Hobby Motor using the integrated circuit L293D.

Why do we need the L293D?

The Arduino cannot provide enough current to drive a motor directly from its pins (it will burn out!). The L293D acts as a "switch": it takes commands from the Arduino and supplies current from an external battery to the motor.

What you will need:

• 1x Arduino Uno
• 1x DC Motor (Type 130)
• 1x L293D motor driver integrated circuit
• 1x Battery Holder (e.g., 4xAA for 6V)
• Breadboard & Wires

The Wiring (The Circuit)

Place the L293D on the breadboard. The semicircle (notch) indicates the "top" side (Pins 1 and 16).

Power Connections:

1. Pin 16 (VCC1): To the 5V of the Arduino (chip power supply).

2. Pin 8 (VCC2): To the (+) of the Battery (motor power supply).

3. GND (Pins 4, 5, 12, 13): Connect all together to the ground (GND) of the Arduino AND to the (-) of the Battery. Attention: They must share a common ground!

Control Connections (Arduino):

1. Pin 1 (Enable 1,2): To Pin 9 of the Arduino (for speed control with PWM).

2. Pin 2 (Input 1): To Pin 3 of the Arduino.

3. Pin 7 (Input 2): To Pin 4 of the Arduino.

Motor Connections:

1. Pin 3 (Output 1): To one wire of the Motor.

2. Pin 6 (Output 2): To the other wire of the Motor.

Upload the following code. The motor will start slowly, accelerate, stop, and then rotate in reverse.

C++

// Pin Definitions const int enablePin = 9; // Controls speed (PWM) const int in1Pin = 3; // Controls direction A const int in2Pin = 4; // Controls direction B void setup() { // Set pins as outputs pinMode(enablePin, OUTPUT); pinMode(in1Pin, OUTPUT); pinMode(in2Pin, OUTPUT); } void loop() { // --- STEP 1: Move Forward --- digitalWrite(in1Pin, HIGH); // One end positive digitalWrite(in2Pin, LOW); // The other end negative // Accelerate from 0 to 255 (Maximum) for (int speed = 0; speed <= 255; speed++) { analogWrite(enablePin, speed); delay(20); } delay(1000); // Wait 1 second // --- STEP 2: Stop --- digitalWrite(in1Pin, LOW); digitalWrite(in2Pin, LOW); analogWrite(enablePin, 0); delay(1000); // --- STEP 3: Move Backward --- digitalWrite(in1Pin, LOW); // Reverse polarity digitalWrite(in2Pin, HIGH); analogWrite(enablePin, 200); // Constant speed (about 80%) delay(2000); // Run for 2 seconds // Stop before repeating the cycle digitalWrite(in1Pin, LOW); digitalWrite(in2Pin, LOW); delay(1000); }

• Rotation Direction: When in1 is HIGH and in2 is LOW, the current flows in one direction. When reversed, the motor spins in the opposite direction.

• Speed: The enablePin acts like the throttle. Using the command analogWrite(enablePin, 255) gives full throttle, while 128 gives half speed.