Windows 10 IoT Core Universal Windows Platform (UWP) implementation for Dexter BrickPi+ board on Raspberry Pi and enabling LEGO MINDSTORMS components to be controlled by Windows 10 IoT Core.
The code has been tested on Raspberry Pi 2 Model B and Raspberry Pi 3 Model B and Windows IoT Core OS from Version 10.0.14393.0 and onwards (Redstone/Anniversary Update).
Lego Mindstorms NXT 2.0 Sensors and Motors are implemented and tested, and many of the HiTechnic sensors and port multiplexer:
- Mindstorms NXT Touch Sensor
- Mindstorms NXT Color sensor (see also Known Issues section )
- Mindstorms NXT Ultrasonic Sensor
- Mindstorms EV3 Touch Sensor (untested)
- HiTechnic NXT Touch Sensor Multiplexer
- HiTechnic Angle Sensor
- HiTechnic Compass Sensor
- HiTechnic Gyro Sensor (legacy)
- HiTechnic EOPD Sensor
- HiTechnic Acceleration & Tilt Sensor
- HiTechnic IR Seeker V2 Sensor
The application uses the Background Application template for Windows IoT Core.
Add a reference to the BrickPi.Uwp library to your project. You can either use the source code version by cloning and compiling this Github repository, or use the BrickPi UWP Windows IoT Core Nuget package.
To install BrickPi UWP Windows IoT Core, run the following command in the Package Manager Console
Install-Package BrickPi.UWP or run the Package Manager UI:
Search for "BrickPi.UWP" package:
Enable the package in the current project
Once the project is created, you need to enable support for serial port capabilities. This can't be done in the UI Manifest editor, so you'll need to text edit the Package.appmanifest file and add (there will be an internetClient capability by default):
<Capabilities>
<Capability Name="internetClient" />
<DeviceCapability Name="serialcommunication">
<Device Id="any">
<Function Type="name:serialPort" />
</Device>
</DeviceCapability>
</Capabilities>First you need to implement a deferal for the background task instance
public sealed class StartupTask : IBackgroundTask
{
BackgroundTaskDeferral deferal;
public async void Run(IBackgroundTaskInstance taskInstance)
{
deferal = taskInstance.GetDeferral();
//....
}
}More details about this can be found in the Developing Background Applications guide.
Next you need to get a reference to the BrickPi instance. The BrickPi is connected to an UART port on the Raspberry, which is referenced by name like "UART0". As current Raspberry Pi only have one UART available, name parameter could be dropped and the first available UART is used
//Need a brick and a serial port
Brick brick = await Brick.InitializeInstance("Uart0");To check basic comnunication with the BrickPi works, and see if a correct firmware version is installed on the BrickPi itself, call the GetBrickVersion() like this:
int version = await brick.GetBrickVersion();
Debug.WriteLine(string.Format("Brick Version: {0}", version));The BrickPi should always return version 2. You should always call GetBrickVersion() before you configure any sensors, as this resets any sensor information. This is due to the fact how the firmware version is queried internally by setting all sensors to a specific (non-existing) sensor type.
Internally, the BrickPi runs two Arduinos on the board. Each Arduino has a tiny blue LED connected, which can be controlled on corresponding GPIO-pins from the RaspBerry Pi. Arduino1 Led is connected to GPIO port 18, corresponding to pin 12 on the RaspBerry Pi 40-pin header, and Arduino2 Led is connected on GPIO port 27, corresponding to pin 13 on the RaspBerry Pi 40-pin header. Further details on GPIO pin mappings can be found at the Raspberry Pi 2 & 3 Pin Mappings overview.
To use the LED in code, you can either set the status (ON or OFF) explicitely, or just toggle from current status
brick.Arduino1Led.Toggle(); //change status from ON to OFF or vice versa
brick.Arduino2Led.Light= true; //explicitely set status to ONMotors (Standard NXT Motors) do not need specific configuration, instances are preinitialized and can be referred through the BrickPi.Motors collection:
Motor motorA = brick.Motors[MotorPort.Port_MA];
Motor motorD = brick.Motors[MotorPort.Port_MD];Using the reference, motors can be enabled and a velocity set. Velocity can be positive or negative to indicate the direction to run.
motorA.Velocity = -50;
motorA.Enabled = true;
//...
motorA.Enabled = false; //set the motor to float
//...
motorA.Velocity = 0; //set the motor to hold at current positionEncoders are part of motors and count motor rotation with 0.5 degree precision (720 ticks per revolution). To set custom encoder count, or reset the encoder, the EncoderOffset property can be used. Setting the EncoderOffset equal to current Encoder count, will reset the Encoder.
int encoderTicks = motorA.Encoder;
//reset the Encoder
motorA.EncoderOffset = motorA.Encoder;Sensor ports need to be initialized with the specific sensor type, as different sensors have different response data format. If not explicitely set, each sensor port is initialized as a RawSensor (technically sending a 10-bit response value), which most analog sensors are using.
Instances of the specific sensor type need to be created, and attached to the Brick.Sensors collection. If multiple sensors will be attached, initialization can be hold until all sensors are created and added to the collection.
NXTTouchSensor touch = new NXTTouchSensor(SensorPort.Port_S1, SensorType.TOUCH_DEBOUNCE);
await brick.Sensors.Add(touch, true); //true to hold initialization until all sensors are attached
NXTUltraSonicSensor ultrasonic = new NXTUltraSonicSensor(SensorPort.Port_S2, SensorType.ULTRASONIC_CONT);
await brick.Sensors.Add(ultrasonic, true);
//...
if (!await brick.InitializeSensors()) //now explicitely call sensor initialization
Debug.WriteLine("Something went wrong initializing sensors");Sensor data actively needs to be polled from the BrickPi. This can be done in a single shot using brick.UpdateValues(). More typically, a continuous loop running polls sensor data and motor encoder data continously. Such loop can be started by calling brick.Start()
Sensor's internal data buffer will be updated either through single or continuous sensor data polling (see above). In the application, sensor data can than be accessed through the various sensor properties, i.e. the UltraSonic sensor has a property for Distance, or Touch Sensor a boolean property indicating if the button is pressed:
Debug.WriteLine(string.Format("NXT Ultrasonic, Distance: {0}, ", ultrasonic.Distance)); //distance in cm
Debug.WriteLine(string.Format("NXT Touch, Is Pressed: {0}, ", touch.Pressed)); //true if pressedInternally, sensor data is held as RawValue, such as 0 or 1 for touch sensor, or different color values for Color Sensor
Debug.WriteLine(string.Format("NXT Color, Raw: {0}", color.RawValue));Sensors will also raise events if sensor values change
touch.OnPressed += Touch_OnPressed;
touch.OnReleased += Touch_OnReleased;
touch.OnChanged += Touch_OnChanged;
//...
private void Touch_OnChanged(object sender, SensorEventArgs e)
{
if ((e as TouchSensorEventArgs).Pressed)
{
brick.Arduino2Led.Light= true;
}
else
{
brick.Arduino2Led.Light = false;
}
}
private void Touch_OnPressed(object sender, SensorEventArgs e)
{
brick.Arduino1Led.Light= true;
}
private void Touch_OnReleased(object sender, SensorEventArgs e)
{
brick.Arduino1Led.Light= false;
}To avoid raising events on noisy data, ie. where ambient light floats, or ultrasonic distance may vary by few cm, a Threshold could be set with some sensors, which means no event will be raised if the change is less than the threshold value.
ultrasonic.Threshold = 5;The BrickPi+ has an onboard MCP3031 chip, connected to the Raspberry I2C bus. This chip can be used to read the current voltage supplied to the Raspberry/BrickPi stack, i.e. to monitor power supply from battery.
Simple read the brick's Voltage property.
Debug.WriteLine($"Voltage {brick.Voltage}V");There is an issue using the Mindstorms NXT 2.0 Color sensor as reported multiple times in BrickPi forum here, here or here, where the sensor does not initialize correctly if running in SensorType.COLOR_FULL (all colors enabled).
To work around, one has to attach the sensor at the first port of a given Arduino (SensorPort.Port_S1 or SensorPort.Port_S3) and leave the next Port unconnected (SensorPort.Port_S2 or SensorPort.Port_S4), but initialize the same color sensor on both ports
//adding NXTColorSensor twice, on S3 and S4, to work around BrickPi issue. Order (S3 or S4 first) does not matter.
NXTColorSensor color = new NXTColorSensor(SensorPort.Port_S4, SensorType.COLOR_FULL);
await brick.Sensors.Add(color, true);
color = new NXTColorSensor(SensorPort.Port_S3, SensorType.COLOR_FULL);
await brick.Sensors.Add(color, true);_