Welcome to Your First Arduino Project! In this lesson, you'll learn how to make an LED blink - the "Hello World" of electronics!
Understanding Digital Output
Digital output is the foundation of controlling electronic devices with a microcontroller. Let's break down what this means.
What is Digital?
In electronics, digital means there are only two possible states:
HIGH
5 Volts (5V)
Logic 1
ON
LOW
0 Volts (0V)
Logic 0
OFF
Think of it like a light switch - it's either ON or OFF, nothing in between!
Pin 13 - The Special Pin
The Arduino Uno has 14 digital pins (numbered 0-13). Pin 13 is special because:
- It has a built-in LED on the Arduino board itself
- It has a built-in resistor for that LED
- Perfect for testing without any external components
- When connecting external LEDs, you still need a resistor!
Essential Arduino Functions
pinMode(pin, mode)
pinMode(pin, mode)
Configures a pin to behave as an INPUT or OUTPUT.
pinMode(13, OUTPUT); // Set pin 13 as an outputParameters:
pin: The pin number (0-13 for digital)mode: EitherINPUTorOUTPUT
digitalWrite(pin, value)
digitalWrite(pin, value)
Sets a digital pin to HIGH (5V) or LOW (0V).
digitalWrite(13, HIGH); // Turn ON (5V)
digitalWrite(13, LOW); // Turn OFF (0V)What happens electrically:
HIGH: Pin outputs 5V, current flows through LED, LED lights up!LOW: Pin outputs 0V, no current flows, LED is off
delay(milliseconds)
delay(milliseconds)
Pauses the program for a specified time.
delay(1000); // Wait for 1000ms = 1 second
delay(500); // Wait for 500ms = 0.5 secondsTime conversion:
- 1000 milliseconds = 1 second
- 500 milliseconds = 0.5 seconds
- 100 milliseconds = 0.1 seconds
Safety First!
- Always use a resistor with external LEDs
- Never exceed 40mA per pin
- Check LED polarity before powering on
- Disconnect USB when changing wiring
LED Anatomy
The flat side of the LED dome indicates the cathode (-)