Example #1
0
  /**
   * [ARGUMENT/OPTION "--pin (#)" | "-p (#)" ] This example program accepts an optional argument for
   * specifying the GPIO pin (by number) to use with this GPIO listener example. If no argument is
   * provided, then GPIO #1 will be used. -- EXAMPLE: "--pin 4" or "-p 0".
   *
   * <p>[ARGUMENT/OPTION "--pull (up|down|off)" | "-l (up|down|off)" | "--up" | "--down" ] This
   * example program accepts an optional argument for specifying pin pull resistance. Supported
   * values: "up|down" (or simply "1|0"). If no value is specified in the command argument, then the
   * pin pull resistance will be set to PULL_UP by default. -- EXAMPLES: "--pull up", "-pull down",
   * "--pull off", "--up", "--down", "-pull 0", "--pull 1", "-l up", "-l down".
   *
   * @param args
   * @throws InterruptedException
   * @throws PlatformAlreadyAssignedException
   */
  public static void main(String[] args)
      throws InterruptedException, PlatformAlreadyAssignedException {

    // ####################################################################
    //
    // since we are not using the default Raspberry Pi platform, we should
    // explicitly assign the platform as the BananaPro platform.
    //
    // ####################################################################
    PlatformManager.setPlatform(Platform.BANANAPRO);

    // create Pi4J console wrapper/helper
    // (This is a utility class to abstract some of the boilerplate code)
    final Console console = new Console();

    // print program title/header
    console.title("<-- The Pi4J Project -->", "GPIO Input Example");

    // allow for user to exit program using CTRL-C
    console.promptForExit();

    // create gpio controller
    final GpioController gpio = GpioFactory.getInstance();

    // ####################################################################
    //
    // When provisioning a pin, use the BananaProPin class.
    //
    // ####################################################################

    // by default we will use gpio pin #01; however, if an argument
    // has been provided, then lookup the pin by address
    Pin pin =
        CommandArgumentParser.getPin(
            BananaProPin.class, // pin provider class to obtain pin instance from
            BananaProPin.GPIO_01, // default pin if no pin argument found
            args); // argument array to search in

    // by default we will use gpio pin PULL-UP; however, if an argument
    // has been provided, then use the specified pull resistance
    PinPullResistance pull =
        CommandArgumentParser.getPinPullResistance(
            PinPullResistance.PULL_UP, // default pin pull resistance if no pull argument found
            args); // argument array to search in

    // provision gpio pin as an input pin
    final GpioPinDigitalInput input = gpio.provisionDigitalInputPin(pin, "MyInput", pull);

    // set shutdown state for this pin: unexport the pin
    input.setShutdownOptions(true);

    // prompt user that we are ready
    console.println("Successfully provisioned [" + pin + "] with PULL resistance = [" + pull + "]");
    console.emptyLine();
    console.box("The GPIO input pin states will be displayed below.");
    console.emptyLine();

    // display pin state
    console.emptyLine();
    console.println(
        " ["
            + input.toString()
            + "] digital state is: "
            + ConsoleColor.conditional(
                input.getState().isHigh(), // conditional expression
                ConsoleColor.GREEN, // positive conditional color
                ConsoleColor.RED, // negative conditional color
                input.getState()));
    console.emptyLine();

    // stop all GPIO activity/threads by shutting down the GPIO controller
    // (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks)
    gpio.shutdown();
  }
  /**
   * [ARGUMENT/OPTION "--pin (#)" | "-p (#)" ] This example program accepts an optional argument for
   * specifying the GPIO pin (by number) to use with this GPIO listener example. If no argument is
   * provided, then GPIO #1 will be used. -- EXAMPLE: "--pin 4" or "-p 0".
   *
   * @param args
   * @throws InterruptedException
   * @throws PlatformAlreadyAssignedException
   */
  public static void main(String[] args)
      throws InterruptedException, PlatformAlreadyAssignedException {

    // ####################################################################
    //
    // since we are not using the default Raspberry Pi platform, we should
    // explicitly assign the platform as the BananaPi platform.
    //
    // ####################################################################
    PlatformManager.setPlatform(Platform.BANANAPI);

    // create Pi4J console wrapper/helper
    // (This is a utility class to abstract some of the boilerplate code)
    final Console console = new Console();

    // print program title/header
    console.title("<-- The Pi4J Project -->", "GPIO Output Example");

    // allow for user to exit program using CTRL-C
    console.promptForExit();

    // create gpio controller
    final GpioController gpio = GpioFactory.getInstance();

    // ####################################################################
    //
    // When provisioning a pin, use the BananaPiPin class.
    //
    // ####################################################################

    // by default we will use gpio pin #01; however, if an argument
    // has been provided, then lookup the pin by address
    Pin pin =
        CommandArgumentParser.getPin(
            BananaPiPin.class, // pin provider class to obtain pin instance from
            BananaPiPin.GPIO_01, // default pin if no pin argument found
            args); // argument array to search in

    // provision gpio pin as an output pin and turn on
    final GpioPinDigitalOutput output =
        gpio.provisionDigitalOutputPin(pin, "My Output", PinState.HIGH);

    // set shutdown state for this pin: keep as output pin, set to low state
    output.setShutdownOptions(false, PinState.LOW);

    // create a pin listener to print out changes to the output gpio pin state
    output.addListener(
        new GpioPinListenerDigital() {
          @Override
          public void handleGpioPinDigitalStateChangeEvent(GpioPinDigitalStateChangeEvent event) {
            // display pin state on console
            console.println(
                " --> GPIO PIN STATE CHANGE: "
                    + event.getPin()
                    + " = "
                    + ConsoleColor.conditional(
                        event.getState().isHigh(), // conditional expression
                        ConsoleColor.GREEN, // positive conditional color
                        ConsoleColor.RED, // negative conditional color
                        event.getState())); // text to display
          }
        });

    // prompt user that we are ready
    console.println(" ... Successfully provisioned output pin: " + output.toString());
    console.emptyLine();
    console.box("The GPIO output pin states will cycle HIGH and LOW states now.");
    console.emptyLine();

    // notify user of current pin state
    console.println(
        "--> ["
            + output.toString()
            + "] state was provisioned with state = "
            + ConsoleColor.conditional(
                output.getState().isHigh(), // conditional expression
                ConsoleColor.GREEN, // positive conditional color
                ConsoleColor.RED, // negative conditional color
                output.getState())); // text to display

    // wait
    Thread.sleep(500);

    // --------------------------------------------------------------------------

    // tset gpio pin state to LOW
    console.emptyLine();
    console.println("Setting output pin state is set to LOW.");
    output.low(); // or ... output.setState(PinState.LOW);

    // wait
    Thread.sleep(500);

    // --------------------------------------------------------------------------

    // tset gpio pin state to HIGH
    console.emptyLine();
    console.println("Setting output pin state from LOW to HIGH.");
    output.setState(PinState.HIGH); // or ... output.high();

    // wait
    Thread.sleep(500);

    // --------------------------------------------------------------------------

    // toggle the current state of gpio pin (from HIGH to LOW)
    console.emptyLine();
    console.println("Toggling output pin state from HIGH to LOW.");
    output.toggle();

    // wait
    Thread.sleep(500);

    // --------------------------------------------------------------------------

    // pulse gpio pin state for 1 second HIGH and then return to LOW
    console.emptyLine();
    console.println("Pulsing output pin state HIGH for 1 second.");
    output.pulse(1000, true); // set second argument to 'true' use a blocking call
    Thread.sleep(50);

    // --------------------------------------------------------------------------

    // blink gpio pin state for 1 second between HIGH and LOW states
    console.emptyLine();
    console.println(
        "Blinking output pin state between HIGH and LOW for 3 seconds with a blink rate of 250ms.");
    Future future = output.blink(250, 3000);

    // --------------------------------------------------------------------------

    // wait for blinking to finish; we are notified in a future object
    while (!future.isDone()) {
      Thread.sleep(50);
    }

    // stop all GPIO activity/threads by shutting down the GPIO controller
    // (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks)
    gpio.shutdown();
  }