Electronics & Arduino Learning Hub

Electronics Fundamentals

⚡ Ohm's Law

The fundamental relationship between voltage, current, and resistance in electrical circuits.

V = I × R

Voltage = Current × Resistance

Interactive Demo:

Voltage (V):

Current (A):

Resistance: 450 Ω

🔋 Voltage & Current

Understanding the flow of electricity and electrical potential difference.

Voltage (V): Electric potential difference - the "pressure" that pushes current through a circuit

Current (I): Flow of electric charge - measured in Amperes (A)

Power (P): P = V × I (Watts)

🔌 Circuit Types

Series vs Parallel circuits and their characteristics.

Series Circuit

Components in a line

Same current everywhere

Voltages add up

Parallel Circuit

Components side by side

Same voltage across each

Currents add up

⚡ Electrical Safety

Essential safety practices when working with electronics.

⚠️ Safety Rules:

Always disconnect power before making connections
Check polarity on batteries and components
Never exceed component voltage/current ratings
Use proper tools and work in a clean environment
Double-check connections before powering on

Resistor Color Code Calculator

🎨 Interactive Resistor Calculator

Select colors to calculate resistance values and learn the color coding system.

Band 1 (1st Digit):

Band 2 (2nd Digit):

Band 3 (Multiplier):

Band 4 (Tolerance):

10 kΩ ±5%

💡 Memory Tip: "Big Boys Race Our Young Girls But Violet Generally Wins"

Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White (0-9)

Arduino Programming Guide

🤖 Arduino Basics

Arduino Uno has 14 digital pins, 6 analog inputs, and operates at 5V. Perfect for learning electronics!

💡 Blink LED Program

The "Hello World" of Arduino programming.

// Blink LED on pin 13
void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
}
                        

LED Status:

📊 Serial Communication

Communicate with your computer for debugging and data logging.

// Serial communication example
void setup() {
  Serial.begin(9600);
  Serial.println("Arduino Ready!");
}

void loop() {
  int sensorValue = analogRead(A0);
  Serial.print("Sensor: ");
  Serial.println(sensorValue);
  delay(500);
}
                        

Arduino Ready!
Sensor: 512
Sensor: 498
Sensor: 523

🎛️ Analog vs Digital

Understanding the difference between analog and digital signals.

Digital Pins (0-13)

HIGH (5V) or LOW (0V)
digitalWrite() & digitalRead()
Perfect for LEDs, buttons

Analog Pins (A0-A5)

0-5V range (0-1023 values)
analogRead() & analogWrite()
Great for sensors

Arduino Projects

🚦 Traffic Light System

Create a realistic traffic light sequence using LEDs.

// Traffic light sequence
int redPin = 13, yellowPin = 12, greenPin = 11;

void setup() {
  pinMode(redPin, OUTPUT);
  pinMode(yellowPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
}

void loop() {
  trafficSequence();
}
                        

🌡️ Temperature Monitor

Read temperature from a sensor and display on serial monitor.

// LM35 temperature sensor
void loop() {
  int reading = analogRead(A0);
  float voltage = reading * 5.0 / 1024.0;
  float temp = voltage * 100.0;
  
  Serial.print("Temperature: ");
  Serial.print(temp);
  Serial.println("°C");
  delay(1000);
}
                        

Temperature: 23.5°C
Temperature: 23.7°C
Temperature: 23.4°C

🔊 Buzzer Alarm System

Create sound alerts with a piezo buzzer and button input.

// Buzzer alarm with button
int buzzerPin = 8, buttonPin = 2;

void setup() {
  pinMode(buzzerPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  if(digitalRead(buttonPin) == LOW) {
    tone(buzzerPin, 1000, 500);
    delay(600);
  }
}
                        

💡 PWM Dimmer

Control LED brightness using Pulse Width Modulation.

// LED brightness control
int ledPin = 9;
int brightness = 0;

void loop() {
  for(brightness = 0; brightness <= 255; brightness++) {
    analogWrite(ledPin, brightness);
    delay(5);
  }
  for(brightness = 255; brightness >= 0; brightness--) {
    analogWrite(ledPin, brightness);
    delay(5);
  }
}
                        

LED Brightness:

Quick Reference Guide

📋 Arduino Functions

Digital I/O

pinMode(pin, mode)
digitalWrite(pin, value)
digitalRead(pin)

Analog I/O

analogRead(pin)
analogWrite(pin, value)
analogReference(type)

Time & Serial

delay(ms) - Pause execution
millis() - Get current time
Serial.begin(baud) - Start serial
Serial.println(data) - Print data

🔧 Component Values

Common Resistor Values (Ω)

220, 330, 470, 1K, 2.2K, 4.7K, 10K, 22K, 47K, 100K

LED Forward Voltages

Red: 1.8-2.2V | Green: 2.0-2.4V | Blue: 3.0-3.4V | White: 3.0-3.6V

Standard Capacitor Values (μF)

0.1, 1, 10, 22, 47, 100, 220, 470, 1000

⚡ Voltage Levels

Arduino Uno Specifications

Operating Voltage: 5V
Input Voltage: 7-12V (recommended)
Digital Pin Current: 20mA max
Analog Resolution: 10-bit (0-1023)
Clock Speed: 16 MHz
Flash Memory: 32KB

🐛 Troubleshooting Tips

Common Issues & Solutions

Code won't upload: Check COM port & board selection
LED not lighting: Check polarity & current limiting resistor
Sensor readings erratic: Add pull-up resistors or capacitors
Serial monitor blank: Check baud rate matches code
Breadboard issues: Check power rails & loose connections

Sensors & Components

🌡️

Temperature Sensors

LM35, DHT22, DS18B20

Measure ambient temperature

💡

Light Sensors

LDR, Photodiode, TSL2561

Detect light intensity

🔊

Sound Sensors

Microphone, Sound detector

Detect sound levels

📏

Distance Sensors

HC-SR04, Sharp IR

Measure distance to objects

🧭

Motion Sensors

PIR, Accelerometer, Gyro

Detect movement & orientation

🌡️

Pressure Sensors

BMP180, BMP280

Measure atmospheric pressure

📏 Ultrasonic Distance Sensor

HC-SR04 sensor for measuring distances up to 4 meters.

// HC-SR04 Ultrasonic Sensor
int trigPin = 9, echoPin = 10;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  delay(100);
}
                        

Distance: 25 cm
Distance: 23 cm
Distance: 28 cm

🌡️ DHT22 Temperature & Humidity

Digital sensor for temperature and humidity readings.

// DHT22 Sensor (requires DHT library)
#include "DHT.h"
DHT dht(2, DHT22);

void setup() {
  Serial.begin(9600);
  dht.begin();
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();
  
  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print("% Temperature: ");
  Serial.print(t);
  Serial.println("°C");
  delay(2000);
}
                        

Humidity: 65% Temperature: 22.5°C
Humidity: 64% Temperature: 22.7°C

💡 Light Dependent Resistor (LDR)

Simple analog sensor that changes resistance with light levels.

// LDR Light Sensor
int ldrPin = A0, ledPin = 13;

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  int lightLevel = analogRead(ldrPin);
  Serial.print("Light Level: ");
  Serial.println(lightLevel);
  
  if(lightLevel < 300) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
  delay(500);
}
                        

Light Level:

Auto LED:

512

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