Circuit Documentation

Summary

This circuit is designed to monitor temperature using an LM35 temperature sensor and control a 28BYJ-48 stepper motor using an Arduino UNO and a ULN2003A breakout board. The motor's rotation direction is determined by the temperature reading: if the temperature exceeds a certain threshold, the motor rotates clockwise; otherwise, it rotates counterclockwise.

Component List

Resistor

• Description: A passive two-terminal electrical component that implements electrical resistance as a circuit element.
• Properties: 220 Ohms resistance.

Arduino UNO

• Description: A microcontroller board based on the ATmega328P. It has digital input/output pins, analog inputs, a USB connection for programming the board, a power jack, an ICSP header, and a reset button.

Temperature Sensor (LM35)

• Description: A precision integrated-circuit temperature device with an output voltage linearly proportional to the Centigrade temperature.
• Properties: Outputs 10mV per degree Celsius.

ULN2003A Breakout Board

• Description: A board that contains the ULN2003A driver chip which is an array of seven NPN Darlington transistors capable of driving a wide range of loads, including solenoids, relays, DC motors, and stepper motors.

28BYJ-48 Stepper Motor

• Description: A small, 5-volt geared stepping motor that can be used whenever precision movement or positioning is required.

Wiring Details

Resistor

• Connections:
  • One end connected to the 5V output of the Arduino UNO.
  • The other end connected to the +Vs pin of the Temperature Sensor (LM35).

Arduino UNO

• Connections:
  • 5V output to the Resistor and ULN2003A breakout board.
  • GND to the Temperature Sensor (LM35) and ULN2003A breakout board.
  • A0 to the Vout pin of the Temperature Sensor (LM35).
  • Digital pins D9, D10, D11, and D12 to the input pins In 1, In 2, In 3, and In 4 of the ULN2003A breakout board, respectively.

Temperature Sensor (LM35)

• Connections:
  • +Vs to the Resistor (connected to 5V of Arduino UNO).
  • Vout to the A0 pin of the Arduino UNO.
  • GND to the GND of the Arduino UNO.

ULN2003A Breakout Board

• Connections:
  • +5V from the Arduino UNO.
  • 0V to the GND of the Arduino UNO.
  • Input pins In 1, In 2, In 3, and In 4 connected to the Arduino UNO digital pins D9, D10, D11, and D12, respectively.
  • Output pins BLUE, PINK, YELLOW, ORANGE, and RED wires to the corresponding pins of the 28BYJ-48 Stepper Motor.

28BYJ-48 Stepper Motor

• Connections:
  • BLUE, PINK, YELLOW, ORANGE, and RED wires to the corresponding output pins of the ULN2003A breakout board.

Documented Code

#include<Stepper.h>

int steps = 2048;
int RPM = 15;
int threshold = 50;
int tempPin = A0;

Stepper assignStepper(steps, 9, 11, 10, 12);

void setup() {
  assignStepper.setSpeed(RPM);
  Serial.begin(9600);
}

void loop() {
  int readValue = analogRead(tempPin);
  float mVout = readValue * (5000.0 / 1023.0);
  float temC = mVout / 10;
  Serial.print(temC);
  Serial.print(" : ");
  if (temC > threshold) {
    Serial.println("Over threshold: Clockwise rotation");
    assignStepper.step(steps);
    delay(1000);
  } else {
    Serial.println("Under threshold: Counterclockwise rotation");
    assignStepper.step(-steps);
    delay(1000);
  }
}

Filename: sketch.ino

Description: This Arduino sketch reads the temperature from the LM35 sensor and converts it to Celsius. If the temperature is above the threshold, the stepper motor is rotated clockwise; otherwise, it is rotated counterclockwise. The stepper motor is controlled via the ULN2003A breakout board.