Mission 05 · Stage 1

Multiple LED Patterns

nested loops and pattern tables

Show different bar graph patterns stored in tables and loops.

Pin connections

Part 1		Part 2
Arduino pin 2	→	LED bar graph A1
Arduino pin 3	→	LED bar graph A2
Arduino pin 4	→	LED bar graph A3
Arduino pin 5	→	LED bar graph A4
Arduino pin 6	→	LED bar graph A5
Arduino pin 7	→	LED bar graph A6
Arduino pin 8	→	LED bar graph A7
Arduino pin 9	→	LED bar graph A8
Arduino pin 10	→	LED bar graph A9
Arduino pin 11	→	LED bar graph A10
LED bar graph C10	→	Arduino GND

See it

Let's make light shapes!

A row of lights shows stripes, then pairs, then a glowing block — again and again.

Big screens and scoreboards show saved shapes just like this!

The story

The problem

Typing every single light by hand is a lot of work. Let's save the shapes and reuse them.

Think of it like

It's like a coloring book — the shapes are drawn once, and you fill them in again and again.

Meet the parts

Holds all the parts and joins them, like a LEGO baseplate.

Breadboard

Our building board

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It reads the saved shapes and tells the lights what to do.

Arduino

The brain

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Ten little lights in a line that make the shapes.

LED bar graph

The row of lights

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How it works

Show the stripes

patternA is a list of 1s and 0s. A 1 means a light glows and a 0 means it stays dark — together they make stripes.

showPattern(patternA);
delay(400);

Show the pairs

patternB is a different list, so the lights make a different shape — two on, two off.

showPattern(patternB);
delay(400);

Show the middle block

patternC lights up the middle lights. Then loop() jumps back to the stripes and does it all again!

showPattern(patternC);
delay(400);

Then loop back to step 1

Build the circuit

Follow these steps in order. Match the wires to the colors shown.

1
Place Breadboard
Place the Breadboard (bb1) on the breadboard.
Breadboard placed — build like the real world!
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2
Place Arduino
Place the Arduino (uno) on the breadboard.
Arduino placed — ready to build!
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3
Place LED bar graph
Place the LED bar graph (bar1) on the breadboard.
Row of ten lights placed — now let's wire them up!
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4
Connect Arduino pin 2 to LED bar graph (bar1) A1
Arduino pin 2 to segment 1's anode (A1)
Tip: Arduino pin 2 to segment 1's anode (A1)
Light 1 wired!
5
Connect Arduino pin 3 to LED bar graph (bar1) A2
Arduino pin 3 to segment 2's anode (A2)
Tip: Arduino pin 3 to segment 2's anode (A2)
Light 2 wired!
6
Connect Arduino pin 4 to LED bar graph (bar1) A3
Arduino pin 4 to segment 3's anode (A3)
Tip: Arduino pin 4 to segment 3's anode (A3)
Light 3 wired!
7
Connect Arduino pin 5 to LED bar graph (bar1) A4
Arduino pin 5 to segment 4's anode (A4)
Tip: Arduino pin 5 to segment 4's anode (A4)
Light 4 wired!
8
Connect Arduino pin 6 to LED bar graph (bar1) A5
Arduino pin 6 to segment 5's anode (A5)
Tip: Arduino pin 6 to segment 5's anode (A5)
Light 5 wired!
9
Connect Arduino pin 7 to LED bar graph (bar1) A6
Arduino pin 7 to segment 6's anode (A6)
Tip: Arduino pin 7 to segment 6's anode (A6)
Light 6 wired!
10
Connect Arduino pin 8 to LED bar graph (bar1) A7
Arduino pin 8 to segment 7's anode (A7)
Tip: Arduino pin 8 to segment 7's anode (A7)
Light 7 wired!
11
Connect Arduino pin 9 to LED bar graph (bar1) A8
Arduino pin 9 to segment 8's anode (A8)
Tip: Arduino pin 9 to segment 8's anode (A8)
Light 8 wired!
12
Connect Arduino pin 10 to LED bar graph (bar1) A9
Arduino pin 10 to segment 9's anode (A9)
Tip: Arduino pin 10 to segment 9's anode (A9)
Light 9 wired!
13
Connect Arduino pin 11 to LED bar graph (bar1) A10
Arduino pin 11 to segment 10's anode (A10)
Tip: Arduino pin 11 to segment 10's anode (A10)
All ten lights are wired!
14
Connect LED bar graph (bar1) C10 to Arduino GND
One wire from the bar graph's common cathode side to Arduino GND — all segments share this ground inside the part
Tip: One wire from the bar graph's common cathode side to Arduino GND — all segments share this ground inside the part
Circuit complete — the shapes can play!

Try it

Press the green Run button — try to name each shape before it changes.
The shapes come from the saved lists at the top — not magic!

Peek at code

The saved shapes

const byte patternA[] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
const byte patternB[] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1};
const byte patternC[] = {0, 0, 0, 0, 1, 1, 1, 1, 0, 0};

Each list holds 1s and 0s. A 1 means a light glows and a 0 means it stays dark. A new shape is just a new list!

The showPattern helper

void showPattern(const byte *pat) {
  for (int i = 0; i < NUM_LEDS; i++) {
    digitalWrite(FIRST_PIN + i, pat[i] ? HIGH : LOW);
  }
}

This little helper reads a shape's list and lights each light ON or OFF. We reuse it for every shape.

Play the shapes

void loop() {
  showPattern(patternA);
  delay(400);
  showPattern(patternB);
  delay(400);
  showPattern(patternC);
  delay(400);
}

loop() shows shape A, then B, then C, with a wait between each. That is the whole repeating light show.

Show full sketch (led-patterns.ino)

const int FIRST_PIN = 2;
const int NUM_LEDS = 10;
const byte patternA[] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
const byte patternB[] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1};
const byte patternC[] = {0, 0, 0, 0, 1, 1, 1, 1, 0, 0};
void showPattern(const byte *pat) {
  for (int i = 0; i < NUM_LEDS; i++) {
    digitalWrite(FIRST_PIN + i, pat[i] ? HIGH : LOW);
  }
}
void setup() {
  for (int i = 0; i < NUM_LEDS; i++) {
    pinMode(FIRST_PIN + i, OUTPUT);
  }
}
void loop() {
  showPattern(patternA);
  delay(400);
  showPattern(patternB);
  delay(400);
  showPattern(patternC);
  delay(400);
}

Quick quiz

Q1. Which part runs again and again?

A. loop() ✓
B. setup()
C. pinMode only

Why: Yes! loop() runs again and again, forever.

Q2. Why do we save the shapes in lists like patternA?

A. So we can reuse a shape with one helper ✓
B. To make the Arduino faster
C. To replace pinMode()

Why: Yes! A saved list plus a helper saves us from typing every light by hand.

Code lab — try on your own

Speed up the show — change all the delay(400) numbers to delay(200).
Hint: There are three delay(400) lines inside loop().
Change the first shape — flip a 1 to a 0 (or a 0 to a 1) on line 3.
Hint: Edit the numbers inside the curly braces of patternA.

Code walkthrough

A line-by-line tour of the sketch — the same steps as in Robot Gurukul Studio.

Program overview

Big idea

Every Arduino program has a top part, a setup() part that runs once, and a loop() part that runs again and again.

In this project

A row of ten lights shows three saved shapes, then starts over.

Tip

Read from the top to the bottom. Tap any word or line if you need help!

const int FIRST_PIN = 2;
const int NUM_LEDS = 10;
const byte patternA[] = {1, 0, 1, 0, 1, 0, 1, 0, 1, 0};
const byte patternB[] = {1, 1, 0, 0, 1, 1, 0, 0, 1, 1};
const byte patternC[] = {0, 0, 0, 0, 1, 1, 1, 1, 0, 0};
void showPattern(const byte *pat) {
  for (int i = 0; i < NUM_LEDS; i++) {
    digitalWrite(FIRST_PIN + i, pat[i] ? HIGH : LOW);
  }
}

setup()

Big idea

setup() runs one time when the board turns on.

In this project

It gets all ten light pins (starting at pin 2) ready.

Why here

Things we do only once go inside setup().

void setup() {
  for (int i = 0; i < NUM_LEDS; i++) {
    pinMode(FIRST_PIN + i, OUTPUT);
  }
}

loop()

Big idea

loop() runs again and again, forever.

In this project

This is where the three light shapes take turns on the bar.

Why here

Things that repeat go inside loop().

void loop() {
  showPattern(patternA);
  delay(400);
  showPattern(patternB);
  delay(400);
  showPattern(patternC);
  delay(400);
}

Try this: Change a delay number inside loop(), then press Run to make each shape hold longer.

pinMode

Big idea

pinMode tells a pin if it will listen or push power out.

In this project

It makes each light pin ready to push power to a light.

Why here

It goes in setup() because we only set it once.

    pinMode(FIRST_PIN + i, OUTPUT);

digitalWrite

Big idea

digitalWrite turns a pin ON or OFF.

In this project

It looks at the shape's list and lights each light ON for a 1 or OFF for a 0.

Why here

It goes in loop() so the shapes can keep changing.

    digitalWrite(FIRST_PIN + i, pat[i] ? HIGH : LOW);

delay

Big idea

delay means wait. Nothing else happens while it waits.

In this project

It holds each shape on screen long enough for you to see it.

Why here

Right after we show a shape.

  delay(400);

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