Class rundown (v2.0)


Bluetooth/USB communication

The MindSqualls library connects to the NXT brick using either Bluetooth or USB.

The communication channel to the NXT brick is handled by 3 classes:

Class Function
NxtCommunicationProtocol Implements the NXT protocol.
NxtBluetoothConnection Implements communicating with the NXT using Bluetooth.
NxtUsbConnection Implements communicating with the NXT using USB. (new in v2.0)

If an error occurs, these classes may throw a NxtException, NxtConnectionException, or a NxtCommunicationProtocolException as well as ordinary .Net exceptions like ArgumentException. You will find the definition of these in the NxtExceptions.cs file.

If you are only interested in how to communicate with your NXT brick, it means that you can make do with these 4-5 C# files: NxtCommunicationProtocol.cs, NxtCommunicationProtocolStructures.cs, NxtBluetoothConnection.cs/NxtUsbConnection.cs and NxtExceptions.cs.

The NXT brick

The NxtBrick implements the brick itself. The brick has a commLink for the Bluetooth/USB connection.

It also has a motorArray of 3 motors and a sensorArray of 4 sensors.

The NxtPollable class has a brick field and since NxtMotor and NxtSensor inherits this class, this provides the opposite relation.

Class Function
NxtPollable Implements common functionality for polling a sensor or a motor for sensor-input.
NxtBrick Implements the NXT brick.
NxtMotor Implements a NXT motor.
NxtSensor Implements a generic NXT sensor. This abstract class needs to be overridden for the specific types of NXT sensors.

Note: In previous versions of the API, the NxtMotor and NxtSensor each implemented a brick field. In v1.2 this field has been moved to the NxtPollable class. If you are interested you can see the class-rundown for v1.1 here.

The sensor class hierarchy

Both motors and sensors can be queried for information; The sensors can be polled for their sensor-readings (duh!), and the motor can be polled for their rotation count.

As a result the sensor class hierarchy starts with the NxtPollable classes and includes the NxtMotor class as well as the NxtSensor class and its derived classes:

Class Function
HiTechnicAccelerationSensor (v1.2) Implements the Acceleration / Tilt Sensor sensor from HiTechnic.
HiTechnicCompassSensor Implements the Compass sensor from HiTechnic.
HiTechnicColorSensor (v1.1) Implements the Color sensor from HiTechnic.
NxtActiveSensor,
NxtPassiveSensor, and
NxtDigitalSensor 		According to the LEGO MINDSTORMS NXT Hardware Developer Kit p. 7 sensors is divided into three types: active sensors (e.g. Robotics Invention Systems sensors), passive sensors (e.g. the NXT touch, light, and sound sensors), and digital sensors (e.g. the NXT ultrasonic sensor and the HiTechnic compass sensor). The three abstract classes NxtActiveSensor, NxtPassiveSensor, and NxtDigitalSensor reflect this.

So far there is no classes implementing the NxtActiveSensor class. The NxtPassiveSensor class implements sensors that get their sensor-reading through the GetInputValues() method. The NxtDigitalSensor implements sensors that gets their sensor-reading through the LsWrite()-, LsGetStatus()- and LsRead()-methods using the I2C protocol.
Nxt2ColorSensor (v2.0) Implements the new Color sensor in the NXT 2.0 set.
NxtNoSensor (v1.1) Use this class if you need to blind a sensor port.
NxtLightSensor Implements the Light sensor. The sensor may provide its own light, or it may measure the ambient light.
NxtMotor See above.
NxtPollable Implements a pollable device for the NXT brick i.e. a device that can measurable something.
NxtSensor See above.
NxtSoundSensor Implements the Sound sensor. Readings may be in both the dB and dBA scales.
NxtTouchSensor Implements the Touch sensor.
NxtUltrasonicSensor Implements the Ultrasonic sensor. Readings is in cm units.

Synchronized motors

The NXT brick provides supports for synchronizing two motors. This is practical since it makes it possible to drive the robot on a straight line, without one motor overtaking the other.

The NxtMotorSync class handles this functionality.

Class Function
NxtMotorSync Establishes a relationship between two motors, allowing them to be synchronized.

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