Let's blink the built-in LED and control the external LED.

1. 1
Arduino Tutorial #2
- Blink the built-in LED &
Control the external LED -
Dong Ho Son
POSTECH
Pohang, Korea
donghoson@postech.ac.kr

2. 2
Blink the built-in LED - Overview
 Let’s blink the LED
• Simple code
• Turn on the built-in LED
− Built-in LED for test
− Internally connected to digital pin #13
Source: pixabay.com/photo-2168193

3. 3
Blink the built-in LED - Sketch
 setup() { }
• pinMode(13, OUTPUT);
− Prepare the mode of pin
− We will use pin #13
− We will order to LED  OUTPUT
 loop() { }
• digitalWrite(13, HIGH);
− Turn on the built-in LED
• Delay(1000);
− Need 1 sec (1000ms) to check step-by-step
• digitalWrite(13, LOW);
− Turn off the built-in LED

4. 4
Blink the built-in LED - Result
 Built-in LED blinks!
LED OFF!LED ON!
Source: pixabay.com/photo-2168193

5. 5
Control external LED - Overview
 Jumper cables
• Pin #2  Breadboard
• Breadboard  GND (Ground)
 LED
• Longer lead (Positive)  Pin #2
• Shorter lead (Negative)  Resistor
 Resistor
• Necessary to protect the LED
 Breadboard
• Power rails
− The top and bottom rows of holes are connected horizontally
• Terminal strips
− Remaining holes are connected vertically
Positive
Negative
Power rails
Terminal strips
Source: pixabay

6. 6
Control external LED – Circuit
 Configure the circuit
• Jumper cables
• LED
• Resistor (220 Ohm)
• Breadboard
+-
Source: pixabay.com/photo-2168193

7. 7
Control external LED - Sketch
 setup() { }
• pinMode(2, OUTPUT);
− Prepare the mode of pin
− We will use pin #2
− We will order to LED  OUTPUT
 loop() { }
• digitalWrite(2, HIGH);
− Turn on the built-in LED
• Delay(500);
− Need 0.5 sec (500ms) to check step-by-step
• digitalWrite(2, LOW);
− Turn off the built-in LED

8. 8
Control the external LED - Result
 External LED blinks!
+-
Source: pixabay.com/photo-2168193

9. 9
How to Use a Breadboard
 If you are not familiar with how to use a breadboard, please take a
look at the following tutorial on how to use a breadboard
https://www.sciencebuddies.org/science-fair-projects/references/how-
to-use-a-breadboard
 Watch the video first