Arduino hello world

06 Nov 2015

Using an Arduino board with a GNU/Linux personal computer has become pretty straightforward. The following command will install the required software:

sudo aptitude install arduino-mk

In order to get the file-system permissions to use the USB-serial it is necessary to add the current user to the dialout group. It is necessary to log out and back in after this.

usermod $USER -a -G dialout

For the Arduino Diecimila you then create a Makefile with the following content (see /usr/share/arduino/hardware/arduino/boards.txt for other supported boards).

ARDUINO_DIR = /usr/share/arduino
BOARD_TAG    = diecimila
ARDUINO_PORT = /dev/ttyUSB0
ARDUINO_LIBS =
include /usr/share/arduino/Arduino.mk

Make sure that /dev/ttyUSB0 is the right device! You can do this by inspecting the output of dmesg after plugging in the Arduino device.

Now you can create a sketch file (ino file extension) for programming the micro controller. E.g. a file Blink.ino with the following content:

int led = 13;

void setup() {
  pinMode(led, OUTPUT);
}

void loop() {
  digitalWrite(led, HIGH);
  delay(50);
  digitalWrite(led, LOW);
  delay(50);
}

Finally compile and upload the code:

make
make upload

The source is available on Github: github.com/wedesoft/arduino-hello-world

Update:

It is also possible to switch the LED according to instructions send over the USB serial channel. The following program facilitates this:

int led = 13;

void setup() {
  Serial.begin(9600);
  pinMode(led, OUTPUT);
}

void loop() {
  char c;
  if (Serial.available()) {
    c = Serial.read();
    if (c == '1') {
      digitalWrite(led, HIGH);
      Serial.write("LED on\r\n");
    } else if (c == '0') {
      digitalWrite(led, LOW);
      Serial.write("LED off\r\n");
    } else
      Serial.write("Switch LED on/off using keys '1' and '0'\r\n");
  };
}

After opening screen as a serial terminal, the LED can be controlled using keys ‘1’ and ‘0’:

screen /dev/ttyUSB0 9600

Exit with Ctrl-A \

See also:

Jan Wedekind

Arduino hello world