First Version Of A Binary Die - Arduino Uno Quick Start Manual

BinaryDice/Blink/Blink.ino
const unsigned int LED_PIN = 12;
const unsigned int PAUSE = 500;
void setup() {
pinMode(LED_PIN, OUTPUT);
}
void loop() {
digitalWrite(LED_PIN, HIGH);
delay(PAUSE);
digitalWrite(LED_PIN, LOW);
delay(PAUSE);
}
We ve built a strong foundation for our project, and in the next section we ll
build upon it.

First Version of a Binary Die

You re certainly familiar with a regular die displaying results in a range from
one to six. To emulate such a die exactly with an electronic device, you d need
seven LEDs and some fairly complicated business logic. We ll take a shortcut
and display the result of a die roll in binary.
For a binary die, we need only three LEDs to represent the current result. We
turn the result into a binary number, and for every bit that is set, we light
up a corresponding LED. The following diagram shows how the die results
are mapped to LEDs. (A black triangle stands for a shining LED.)
We already know how to control a single LED on a breadboard. Controlling
three LEDs is similar and requires only more wires, LEDs, 1kΩ resistors, and
pins. Figure 11, A first working version of our binary die, on page 46
the first working version of a binary die.
The most important difference is the common ground. When you need ground
for a single LED, you can connect it to the LED directly. But we need ground
for three LEDs now, so we ll use the breadboard s rows for the first time.
Connect the row marked with a hyphen (-) to the Arduino s ground pin, and
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First Version of a Binary Die 45
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