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

Patterns stored in tables!

Arrays and loops replay different ON/OFF shapes on the bar.

Displays often look up patterns from tables instead of typing each step.

The story

The problem

Writing every LED by hand gets tedious — reuse pattern data.

Think of it like

Like reading sheet music: the notes are written once, played in a loop.

Meet the parts

Runs your sketch

Arduino

Brain

Loading part…

Ten segments you can light up

LED bar graph

Display

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How it works

Show stripes

patternA[] is a table of 1s and 0s — the loop in showPattern() writes each segment ON or OFF.

showPattern(patternA);
delay(400);

Show pairs

patternB[] is a different shape on the bar — same function, different data.

showPattern(patternB);
delay(400);

Show center block

Then loop() starts again with patternA. Tables + loops avoid rewriting every LED by hand.

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 Arduino
Place the Arduino (uno) on the breadboard.
Arduino placed!
Loading part…
2
Place LED bar graph
Place the LED bar graph (bar1) on the breadboard.
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3
Connect Arduino pin 2 to LED bar graph (bar1) A1
Connect Arduino pin 2 to LED bar graph (bar1) A1.
4
Connect Arduino pin 3 to LED bar graph (bar1) A2
Connect Arduino pin 3 to LED bar graph (bar1) A2.
5
Connect Arduino pin 4 to LED bar graph (bar1) A3
Connect Arduino pin 4 to LED bar graph (bar1) A3.
6
Connect Arduino pin 5 to LED bar graph (bar1) A4
Connect Arduino pin 5 to LED bar graph (bar1) A4.
7
Connect Arduino pin 6 to LED bar graph (bar1) A5
Connect Arduino pin 6 to LED bar graph (bar1) A5.
8
Connect Arduino pin 7 to LED bar graph (bar1) A6
Connect Arduino pin 7 to LED bar graph (bar1) A6.
9
Connect Arduino pin 8 to LED bar graph (bar1) A7
Connect Arduino pin 8 to LED bar graph (bar1) A7.
10
Connect Arduino pin 9 to LED bar graph (bar1) A8
Connect Arduino pin 9 to LED bar graph (bar1) A8.
11
Connect Arduino pin 10 to LED bar graph (bar1) A9
Connect Arduino pin 10 to LED bar graph (bar1) A9.
12
Connect Arduino pin 11 to LED bar graph (bar1) A10
Connect Arduino pin 11 to LED bar graph (bar1) A10.
13
Connect LED bar graph (bar1) C10 to Arduino GND
Connect LED bar graph (bar1) C10 to Arduino GND.

Try it

Run and name each shape before it changes.
Patterns come from the arrays — not magic!

Peek at code

Pattern tables

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 array stores which segments are on (1) or off (0). Adding a new look means a new table, not ten new lines.

showPattern()

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

One for-loop walks the table and calls digitalWrite for each segment. Reuse this function for every pattern.

Play patterns in loop

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

loop() calls showPattern three times with pauses — that is the full repeating 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. Where does repeating work belong?

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

Why: Correct—loop() runs again and again.

Q2. Why store patterns in arrays like patternA[]?

A. Reuse the same shape with one loop ✓
B. Make the Arduino faster
C. Replace pinMode()

Why: Correct — a table plus a loop avoids copy-pasting many lines.

Code lab — try on your own

Speed up the show — change all delay(400) to delay(200).
Hint: There are three delay(400) lines in loop().
Flip one segment in patternA — change a 1 to 0 or a 0 to 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 Robo Gurukul Studio.

Program overview

Technical

Sketches have globals, then setup() once, then loop() forever.

In this project

Show different bar graph patterns stored in tables and loops.

Why here

Read from top to bottom. Hover words or lines for 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()

Technical

Runs one time when the board turns on.

In this project

Sets up pins and libraries for Multiple LED Patterns.

Why here

One-time setup belongs here—not in loop().

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

loop()

Technical

Runs again and again after setup() is done.

In this project

This is the main action you see in Multiple LED Patterns.

Why here

Repeating work (blink, read sensors) goes here.

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

Try this: Change numbers in loop(), then compile and run the simulator.

pinMode

Technical

Tells a pin if it listens or drives something.

In this project

Gets the Multiple LED Patterns circuit ready in the simulator.

Why here

Goes in setup() because we only set pins once at the start.

    pinMode(FIRST_PIN + i, OUTPUT);

digitalWrite

Technical

Turns a pin ON or OFF.

In this project

Controls lights, motors, or buzzers in Multiple LED Patterns.

Why here

Goes in loop() so it can keep changing while the program runs.

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

delay

Technical

Waits for some time. Nothing else runs during the wait.

In this project

Controls speed so you can see Multiple LED Patterns in the simulator.

Why here

Right after an action that should stay the same for a moment.

  delay(400);

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