Windows 10 IoT Core

LED Matrix Graphics Library

Graphics Lib to draw, scroll & control text or symbols on multiple 8x8 LED Matrices and Seven Segment Displays (7-Segment Displays). Supports HT16K33, Ht16K33BiColor and the MAX7219 LED Matrix Driver chips

This project makes it really easy to add graphics to your Windows 10 for IoT project running on Raspberry Pi 2 or the Minnow Max Board.

The main graphics library includes a font set, symbols and support for drawing lines, boxes, dots plus support for scrolling text across multiple display panels for form a larger frame.

The library includes three LED Matrix drivers and the library is designed to be extensible making it easy to add new LED drivers.

The MAX7219 LED driver supports chaining and rotation of multiple LED Matrix display and Seven Segment Displays (7-Segment) panels together over a single SPI line. These modules are cheap, readily available and a chain of four panels can be purchased on eBay for about $US6.

The HT16K33 I2C driver supports two implementations. The Adafruit Mini 8x8 LED Matrix with I2C Backpack, and the Adafruit Bicolor LED Square Pixel Matrix with I2C Backpack. These can be chained and rotated together but each display panel must have a unique I2C address.

The Glovebox.Graphics Library is also available on NuGet.

#LED Maxtrix Hello World Example

using Glovebox.Graphics.Components;
using Glovebox.Graphics.Drivers;
using Windows.ApplicationModel.Background;

// The Background Application template is documented at https://go.microsoft.com/fwlink/?LinkID=533884&clcid=0x409&WT.mc_id=iot-0000-dglover

namespace HelloWorld {
	public sealed class StartupTask : IBackgroundTask
	{
		BackgroundTaskDeferral _deferral;   // for a headless Windows 10 for IoT projects you need to hold a deferral to keep the app active in the background

		public void Run(IBackgroundTaskInstance taskInstance) {
			_deferral = taskInstance.GetDeferral();  // request the deferral

			MAX7219 driver = new MAX7219(4, MAX7219.Rotate.D90, MAX7219.ChipSelect.CE0);  // 4 panels, rotate 90 degrees, SPI CE0
			LED8x8Matrix matrix = new LED8x8Matrix(driver);     // pass the driver to the LED8x8Matrix Graphics Library

			while (true) {
				matrix.ScrollStringInFromRight("Hello World 2015", 100);
			}
		}
	}
}

#Seven Segment Display Example

using Glovebox.Graphics.Components;
using Glovebox.Graphics.Drivers;
using Glovebox.IoT.Devices.Sensors;
using System;
using System.Text;
using System.Threading.Tasks;
using Windows.ApplicationModel.Background;

namespace SevenSegmentDisplaySample {
    public sealed class StartupTask : IBackgroundTask {

        BackgroundTaskDeferral _deferral;   // for a headless Windows 10 for IoT projects you need to hold a deferral to keep the app active in the background
        double temperature;
        bool blink = false;
        StringBuilder data = new StringBuilder(40);

        public void Run(IBackgroundTaskInstance taskInstance) {
            _deferral = taskInstance.GetDeferral();  // get the deferral handle

            int count = 0;

            MAX7219 driver = new MAX7219(2);
            SevenSegmentDisplay ssd = new SevenSegmentDisplay(driver);
            BMP180 bmp = new BMP180(BMP180.Mode.HIGHRES);

            ssd.FrameClear();
            ssd.FrameDraw();
            ssd.SetBrightness(4);

            while (true) {
                temperature = bmp.Temperature.DegreesCelsius;

                data.Clear();

                // is temperature less than 3 digits and there is a decimal part too then right pad to 5 places as decimal point does not take up a digit space on the display
                if (temperature < 100 && temperature != (int)temperature) { data.Append($"{Math.Round(temperature, 1)}C".PadRight(5)); }
                else { data.Append($"{Math.Round(temperature, 0)}C".PadRight(4)); }

                data.Append(Math.Round(bmp.Pressure.Hectopascals, 0));

                if (blink = !blink) { data.Append("."); }  // add a blinking dot on bottom right as an I'm alive indicator

                ssd.DrawString(data.ToString());

                ssd.DrawString(count++, 1);

                ssd.FrameDraw();

                Task.Delay(2000).Wait();
            }
        }
    }
}

Be sure to review the examples in the Example Project for more extensice samples

Raspberry Pi 2 Pin Mappings

MinnowBoard Max Pin Mapings

LED Matrix Drivers

##MAX7219 SPI LED Driver

MAX7219 based LED matrices are great, they are simple to chain together and they connect to the Raspberry Pi via either SPI channel. Oh, and best of all they are cheap. You can buy 4 chained 8x8 LED matrices for about $US6 off eBay. Now that's a lot of LEDs for not a lot of money!

This LED Matrix can only display one colour, so there is a Led palette in the Pixel class. Led.On() and led.Off() to turn a pixel on or off. But actually you can use any Pixel colour you like other than Black to turn a pixel on.

###Wiring

GPIO pin-outs

The breakout board has two headers to allow daisy-chaining.

Name	Remarks	RPi Pin	RPi Function
VCC	+5V Power	2	5V0
GND	Ground	6	GND
DIN	Data In	19	GPIO 10 (MOSI)
CS	Chip Select	24	GPIO 8 (SPI CE0)
CLK	Clock	23	GPIO 11 (SPI CLK)

###Examples

MAX7219 driver = new MAX7219()  // create new MAX7219 LED Matrix driver and take all the defaults

MAX7219 driver = new MAX7219(4, MAX7219.Rotate.D90, MAX7219.ChipSelect.CE0);  // 4 panels, rotate 90 degrees, SPI CE0

###Constructors

Name	Description
MAX7219()	Defaults to 1 Display Panel, No rotation, SPI CE0, SPI Controller Name SPI0
MAX7219(numOfPanels)	Number of chained Display Panels
MAX7219(numOfPanels, rotate)	Number of chained Display Panels. Rotate each display panel none, 90 degrees, 180 degrees
MAX7219(numOfPanels, rotate, chipSelect)	Number of chained Display Panels. Rotate each display panel none, 90 degrees, 180 degrees. SPI Chip Select CE0, CE1
MAX7219(numOfPanels, rotate, chipSelect, SPIControllerName)	Number of chained Display Panels. Rotate each display panel none, 90 degrees, 180 degrees. SPI Chip Select CE0, CE1. SPIControllerName = SPI0 on Raspberry Pi and MinnowBoard Max

##Class Ht16K33 I2C LED Driver

This Adafruit 8x8 LED Matrix is a great way to add status to your project. They are available in multiple colours, from Red, to Green, yellow, white and more. You can create a wide display panel using multiple of these LED Matrices and treat them as one panel.

This LED Matrix can only display one colour, so there is a Mono colour palette in the Pixel class. Mono.On and Mono.Off to turn a pixel on or off. But actually you can use any Pixel colour you like other than Black to turn a pixel on.

###Wiring

GPIO pin-outs

The breakout board has two headers to allow daisy-chaining.

Name	Remarks	RPi Pin	RPi Function
VCC	+5V Power	2	5V0
GND	Ground	6	GND
SDA	Serial Data Line	3	I2C1 SDA
SCL	Serial Clock Line	5	I2C1 SCL

###Examples

Ht16K33 driver = new Ht16K33(new byte[] { 0x70, 0x72 }, Ht16K33.Rotate.None);  // pass in two I2C Addresses for the panels to be treated as one display panel 

Ht16K33 driver = new Ht16K33() // create new driver and take defaults - I2C Address 0x70

###Constructors

Name	Description
Ht16K33()	Defaults: I2C Address = 0x70, Rotate = none, Display on, Brightness 2 (0-15), I2C Controller Name I2C1
Ht16K33(new byte[] { 0x70 })	Collection of I2C Addresses. Specify if not using the default 0x70 address or you are chaining multiple I2C LED Matrices together in to one long display panel
Ht16K33(new byte[] { 0x70 }, Ht16K33.Rotate.None)	Rotate none, 90 degress, 180 degress)
Ht16K33(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On)	Display on or off
Ht16K33(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2)	Brightness 0-15
Ht16K33(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2, LedDriver.BlinkRate.Off)	Blink off, slow, medium, fast
Ht16K33(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2, LedDriver.BlinkRate.Off, "I2C1")	I2C Controller name: I2C1 for Raspberry Pi, I2C5 for MinnowBoard Max

##Class Ht16K33BiColor

The Adafruit Bicolor LED Square Pixel Matrix with I2C Backpack are a great way to add a little more colour to your projects. With two LEDS, a Red and a Green you can actually combine and create three colours. Red, Green and Yellow, nice.

You can create a wide display panel using multiple of these LED Matrices and treat them as one panel.

The Pixel class includes a three colour palette, BiColour.Red, BiColour.Green and BiColor.Yellow to control this baby.

###Wiring

GPIO pin-outs

The breakout board has two headers to allow daisy-chaining.

Name	Remarks	RPi Pin	RPi Function
VCC	+5V Power	2	5V0
GND	Ground	6	GND
SDA	Serial Data Line	3	I2C1 SDA
SCL	Serial Clock Line	5	I2C1 SCL

###Examples

Ht16K33 driver = new Ht16K33(new byte[] { 0x70, 0x72 }, Ht16K33.Rotate.None);  // pass in two I2C Addresses for the panels to be treated as one display panel 

Ht16K33 driver = new Ht16K33() // create new driver and take defaults - I2C Address 0x70

###Constructors

Name	Description
Ht16K33BiColor()	Defaults: I2C Address = 0x70, Rotate = none, Display on, Brightness 2 (0-15), I2C Controller Name I2C1
Ht16K33BiColor(new byte[] { 0x70 })	Collection of I2C Addresses. Specify if not using the default 0x70 address or you are chaining multiple I2C LED Matrices together in to one long display panel
Ht16K33BiColor(new byte[] { 0x70 }, Ht16K33.Rotate.None)	Rotate none, 90 degress, 180 degress)
Ht16K33BiColor(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On)	Display on or off
Ht16K33BiColor(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2)	Brightness 0-15
Ht16K33BiColor(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2, LedDriver.BlinkRate.Off)	Blink off, slow, medium, fast
Ht16K33BiColor(new byte[] { 0x70 }, Ht16K33.Rotate.None, LedDriver.Display.On, 2, LedDriver.BlinkRate.Off, "I2C1")	I2C Controller name: I2C1 for Raspberry Pi, I2C5 for MinnowBoard Max

#LED Matrix Manager

##Class LED8x8Matrix

###Constructors

Name	Description
LED8x8Matrix(driver)	Pass in a MAX7219 or Ht16K33 or Ht16K33BiColor LED Matrix driver.

###Examples

LED8x8Matrix matrix = new LED8x8Matrix(new MAX7219());  // take the defaults for the MAX7219 LED Matrix driver


MAX7219 driver = new MAX7219(4, MAX7219.Rotate.D90, MAX7219.ChipSelect.CE0);  // 4 panels, rotate 90 degrees, SPI CE0
LED8x8Matrix matrix = new LED8x8Matrix(driver);     // pass the driver to the LED8x8Matrix Graphics Library

###Methods

Row and Column Roll Operators

• ColumnRollUp
• ColumnRollDown
• ColumnRollLeft
• ColumnRollRight
• ColumnShiftLeft
• ColumnShiftRight

Row and Column Line Draw Operators

• ColumnDrawLine
• RowDrawLine

Frame Operators

A Frame is multiple display panels treated as one display frame

• FrameRollUp
• FrameRollDown
• FrameRollLeft
• FrameRollRight
• FrameShiftLeft
• FrameShiftRight

Draw Operators

• DrawBitmap
• DrawBox
• DrawLetter
• DrawString
• DrawSymbol

###Scroll Operators

• ScrollBitmapInFromLeft
• ScrollBitmapInFromRight
• ScrollCharacterFromLeft
• ScrollCharacterFromRight
• ScrollStringInFromLeft
• ScrollStringInFromRight
• ScrollSymbolInFromLeft
• ScrollSymbolInFromRight

###Frame Privatives

• FrameClear
• FrameDraw

Frame Set Primatives

• FrameSet
• FrameSetBlocks

###Shift Primatives

• FrameShift
• FrameShiftBack
• FrameShiftForward

Pixel Point Primatives

• FramePixelForward
• FramePixelSwap
• PointColour
• PointPostion

Spin Primatives - Circular LED Strings

• SpinColour
• SpinColourOnBackground

LED Control

• SetBlinkRate
• SetBrightness
• SetFrameState

Properties

Property	Description
ColumnsPerPanel	Number of columns per panel
RowsPerPanel	Number of rows per panel
PixelsPerPanel	Number of pixels per panel. ColumnsPerPanel x RowsPerPanel
PanelsPerFrame	Multiple panels make up a frame
ColumnsPerFrame	Total columns across a frame
RowsPerFrame	Total rows down a frame
Length	Total number of Pixels in the Frame. PixelsPerPanel x PanelsPerFrame