Circuit Documentation

Summary

This circuit consists of an Arduino Nano microcontroller, a ULN2003A breakout board, a 28BYJ-48 stepper motor, and a rotary potentiometer. The Arduino Nano reads the analog value from the potentiometer and controls the stepper motor speed through the ULN2003A driver.

Component List

Arduino Nano

• Description: A small, complete, and breadboard-friendly board based on the ATmega328P.
• Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

ULN2003A Breakout Board

• Description: A Darlington transistor array used to drive the stepper motor.
• Pins: In 1, In 2, In 3, In 4, In 5, In 6, In 7, 0V, +5V, ON/OFF jumper switch, BLUE wire, PINK wire, YELLOW wire, ORANGE wire, RED wire

28BYJ-48 Stepper Motor

• Description: A small, inexpensive, and easy-to-use stepper motor.
• Pins: BLUE, PINK, YELLOW, ORANGE, RED

Rotary Potentiometer

• Description: A variable resistor used to provide an analog input to the Arduino.
• Pins: leg1, wiper, leg2
• Properties:
  • Resistance: 10,000 Ohms

Wiring Details

Arduino Nano

• GND connected to ULN2003A breakout board 0V
• D8 connected to ULN2003A breakout board In 1
• D9 connected to ULN2003A breakout board In 2
• D10 connected to ULN2003A breakout board In 3
• D11/MOSI connected to ULN2003A breakout board In 4
• VIN connected to Rotary Potentiometer leg1
• GND connected to Rotary Potentiometer leg2
• 5V connected to ULN2003A breakout board +5V
• A0 connected to Rotary Potentiometer wiper

ULN2003A Breakout Board

• 0V connected to Arduino Nano GND
• In 1 connected to Arduino Nano D8
• In 2 connected to Arduino Nano D9
• In 3 connected to Arduino Nano D10
• In 4 connected to Arduino Nano D11/MOSI
• +5V connected to Arduino Nano 5V
• BLUE wire connected to 28BYJ-48 Stepper Motor BLUE
• PINK wire connected to 28BYJ-48 Stepper Motor PINK
• YELLOW wire connected to 28BYJ-48 Stepper Motor YELLOW
• ORANGE wire connected to 28BYJ-48 Stepper Motor ORANGE
• RED wire connected to 28BYJ-48 Stepper Motor RED

28BYJ-48 Stepper Motor

• BLUE connected to ULN2003A breakout board BLUE wire
• PINK connected to ULN2003A breakout board PINK wire
• YELLOW connected to ULN2003A breakout board YELLOW wire
• ORANGE connected to ULN2003A breakout board ORANGE wire
• RED connected to ULN2003A breakout board RED wire

Rotary Potentiometer

• leg1 connected to Arduino Nano VIN
• wiper connected to Arduino Nano A0
• leg2 connected to Arduino Nano GND

Code Documentation

Arduino Nano Code

#include <Stepper.h>

const int stepsPerRevolution = 200;  
Stepper myStepper(stepsPerRevolution, 4, 5, 6, 7);
int stepCount = 0;  

void setup() {
}

void loop() {
   int sensorReading = analogRead(A0);
   int motorSpeed = map(sensorReading, 0, 1023, 0, 100);
   if (motorSpeed > 0) {
    myStepper.setSpeed(motorSpeed);
    myStepper.step(stepsPerRevolution / 100);
  }
}

This code initializes a stepper motor with 200 steps per revolution. In the loop function, it reads the analog value from pin A0 (connected to the potentiometer), maps this value to a motor speed, and if the speed is greater than 0, it sets the motor speed and steps the motor.