IoT: Simple LED Blink example

This article helps you to work with a simple experiment of connecting LED lights with Raspberry Pi device (device only with Windows 10 IoT Core OS)

Requirements:

• Raspberry Pi 2/3 with Windows 10 IoT Core OS connected to internet
• Laptop or PC with Windows 10 OS connected to internet
• Visual Studio 2015 installed on your laptop or PC
• Bread Board
• LED Light
• Resistor

Follow the below steps:

**Step – 01: **Select File -> Create new project -> Name it "Simple Led Blink" 

**  **

**Step – 02: **Right click on the selection and add reference. Select Windows IoT Extention for the UWP and click ok.

**Step – 03: **Open MainPage.xaml and add the following for UI

<Grid Background="Wheat">
        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
            <Ellipse x:Name="LED" Fill="LightGray" Stroke="White" Width="100" Height="100" Margin="10"/>
            <TextBlock x:Name="DelayText" Text="500ms" Margin="10" TextAlignment="Center" FontSize="26.667" />
            <TextBlock x:Name="GpioStatus" Text="Waiting to initialize GPIO..." Margin="10,50,10,10" TextAlignment="Center" FontSize="26.667" />
        </StackPanel>
    </Grid>

**Step – 04: **Open the MainPage.xaml.cs add the following in the cs file.

    private const  int LED_PIN =5;
    private GpioPin pin;
    private GpioPinValue pinValue;
    private DispatcherTimer timer;
    private SolidColorBrush redBrush = new SolidColorBrush(Windows.UI.Colors.Red);
    private SolidColorBrush grayBrush = new SolidColorBrush(Windows.UI.Colors.LightGray);
  
    public MainPage()
    {
        InitializeComponent();
  
        timer = new  DispatcherTimer();
        timer.Interval = TimeSpan.FromMilliseconds(500);
        timer.Tick += Timer_Tick;
        InitGPIO();
        if (pin != null)
        {
            timer.Start();
        }
    }
  
    private void  InitGPIO()
    {
        var gpio = GpioController.GetDefault();
  
        // Show an error if there is no GPIO controller
        if (gpio == null)
        {
            pin = null;
            GpioStatus.Text = "There is no GPIO controller on this device.";
            return;
        }
  
        pin = gpio.OpenPin(LED_PIN);
        pinValue = GpioPinValue.High;
        pin.Write(pinValue);
        pin.SetDriveMode(GpioPinDriveMode.Output);
  
        GpioStatus.Text = "GPIO pin initialized correctly.";
  
    }
  
    private void  Timer_Tick(object  sender, object  e)
    {
        if (pinValue == GpioPinValue.High)
        {
            pinValue = GpioPinValue.Low;
            pin.Write(pinValue);
            LED.Fill = redBrush;
        }
        else
        {
            pinValue = GpioPinValue.High;
            pin.Write(pinValue);
            LED.Fill = grayBrush;
        }
    }
  
}

In the above code we are using the GPIO(General purpose input output ports) for the interaction of the electronic circuit. We are using GPIO 5 over here

Connect the following circuit

Once the circuit is connected, build the solution.

**Step – 05: **Now build the solution and select ARM and select Remote Machine

In the address column enter the ip address of the network connected with Raspberry Pi device and click ok.

**Step – 06: **Now once Remote Machine is selected build and run the application. Once the application is build & run operation is completed successfully in the sense you will find the LED blinking according to the timer set.