Source

Scott Fitzgerald and Michael Shiloh, The Arduino Projects Book Chapter 2: Spaceship Interface

Contents

Install arduino-cli, run script from command line

https://arduino.github.io/arduino-cli/0.20/getting-started/

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$ brew install arduino-cli
$ arduino-cli core update-index
$ arduino-cli board list
Port                            Protocol Type              Board Name  FQBN            Core
/dev/cu.usbmodem143301          serial   Serial Port (USB) Arduino Uno arduino:avr:uno arduino:avr
$ arduino-cli core install arduino:avr
$ arduino-cli core list
ID          Installed Latest Name
arduino:avr 1.8.4     1.8.4  Arduino AVR Boards
$ arduino-cli sketch new project_first
$ arduino-cli compile --fqbn arduino:avr:uno project_first
$ arduino-cli upload -p /dev/cu.usbmodem143301 --fqbn arduino:avr:uno project_first

Good to know how to do this, but henceforth I’ll use Microsoft’s Arduino extension for Visual Studio Code.

Arduino board pins and electronic components connected to them

Assign board pins input/output roles. You will set each pin to INPUT or OUTPUT in setup(), below.

Pin for pushbutton:

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int inputPins[] = {2};

Pins for LEDs:

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int outputPins[] = {LED_BUILTIN, 3, 4, 5};

After connecting breadboard pushbutton and LEDs to Arduino board pins, identify the pins here.

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int pushButton = 2;
int greenLED = 3;
int redLED1 = 4;
int redLED2 = 5;

Possible states of an output pin.

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int ledStates[] = {HIGH, LOW};

Set starting state of breadboard pushbutton.

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int pushButtonState = LOW;

setup() and loop()

Are run when the program loads.

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void setup() {

    // Set pin modes.
    for (int pin : inputPins) pinMode(pin, INPUT);
    for (int pin : outputPins) pinMode(pin, OUTPUT);
    
    // You may want to set the initial state of a component. Here, turn
    // the green breadboard LED on.
    digitalWrite(greenLED, HIGH);
}


void loop() {

    // Get pushbutton state.
    pushButtonState = digitalRead(pushButton);

    // Respond to changes in a pin value.
    // When button is down...
    if (pushButtonState == HIGH) {

        // ...turn green LED off...
        digitalWrite(greenLED, LOW);

        // ... and turn on red LEDs.
        digitalWrite(redLED1, HIGH);
        digitalWrite(redLED2, HIGH);

    } else {

        // When button is up, turn green LED on...
        digitalWrite(greenLED, HIGH);

        // ... and turn off red LEDs.
        digitalWrite(redLED1, LOW);
        digitalWrite(redLED2, LOW);
        }
}