This example illustrates communication with a Lego Mindstorms NXT brick using text commands sent over the Bluetooth Serial Port Profile. Before setting up a connection in MATLAB, the NXT brick has to be paired with your computer. Once this is done, the device will be visible in MATLAB.To get a list of all the available Bluetooth devices use the instrhwinfo command. Get the "friendly" names of the Bluetooth devices available using the RemoteNames field from the output of instrhwinfo.Get the details of the NXT brick.The device's RemoteName is NXT and its Channel is 1. Construct a bluetooth object called bt as shown by the ObjectConstructorName in the previous step.Now connect to the device.The Lego Mindstorms data sheet defines a protocol for communicating with NXT brick. It specifies that to get the device information, the command should have following format:Bytes 1:2 - Length of commandByte 3 - Type of commandByte 4 - Additional information to execute the commandUsing this information, raw data packet is formed which is sent to the NXT brick.
Bytes 1:2 - Length of command = 2Byte 3 - Type of command = 1 (since it is a system command with reply from device)Byte 4 - 0x9B (This value is defined by the Lego Mindstorms NXT communication protocol)This translates the raw data packet to be: [2 0 1 155]. Write this data to the brick.The device then gives a response containing device information. The response has following format:Bytes 1:2 - Length of responseByte 3 - Type of command issuedByte 4 - Data sent to deviceByte 5 - Command statusBytes 6:20 - Name of device (14 characters + null terminator)Bytes 21:27 - Bluetooth addressByte 28 - LSB of Bluetooth signal strengthByte 31 - MSB of Bluetooth signal strengthByte 32 - LSB of user flashByte 35 - MSB of user flashNow read the response from the brick to get its informationIn this example, the response from the NXT brick is:Bytes 1:2 - Length of response = 33Byte 3 - Type of command issued = 2Byte 4 - Data sent to device = 0x9BByte 5 - Command status = 0 (command was successful)Bytes 6:20 - Name of device (14 characters + null terminator)Bytes 21:27 - Bluetooth addressByte 28 - LSB of Bluetooth signal strength = 0Byte 29 - Not defined = 0Byte 30 - Not defined = 0Byte 31 - MSB of Bluetooth signal strength = 0Byte 32 - LSB of user flash = 0Byte 33 - Not defined = 0Byte 34 - Not defined =
0Byte 35 - MSB of user flash = 132Let us now read only the name of the brick from its response. We know that bytes 6 to 20 corresspond to the brick's name.Clear the buffer of the Bluetooth objectLet us now play a tone at frequency 1500 Hz for 1000 ms on the brick. The Lego Mindstorms NXT direct commands define a command to play a tone on the brick as follows:Bytes 1:2 - Length of commandByte 3 - Type of commandBytes 5:6 - Frequency of the tone in HzBytes 7:8 - Duration of the tone in msIn this example, the raw data packet is formed as follows:Byte 1:2 - Length of command = 6Byte 3 - Type of command = 0 (since it is a direct command with reply from device)Byte 4 - Message id = 3Bytes 5:6 - Frequency of the tone is 1500Hz, which translates to uint8[220 5]Bytes 7:8 - Duration of the tone is 1000 ms, which translates to uint8[232 3]Hence the command to be written to the brick is [6 0 0 3 220 5 232 3].In addition to the audio tone played on the NXT brick, the device also gives a 5 byte response.
Let us now read the response from the brick. The response has the following format:Byte 1:2 - Length of responseByte 3 - Type of command issuedIn this example, the response from the NXT brick is:Byte 1:2 - Length of response = 3Byte 3 - Type of command issued = 2Byte 4 - Message id = 3Byte 5 - Status byte = 0 (command was successful)You can get more information on communicating with Lego Mindstorms NXT using high level commands here.NI Home > Products & Services > Academic Products > Academic Software > NI LabVIEW > LabVIEW for Secondary Schools > NI LabVIEW for LEGO® MINDSTORMS® NI LabVIEW for LEGO® MINDSTORMS® 2014 Primary and Secondary Education License Only Not valid for universities or colleges. Professional software customized for K-12 classroom use Most advanced software environment for programming the NXT\EV3 device Manage your NXT\EV3 device better with a custom graphical screen for advanced projects Build your perfect learning station by adding sensors and TETRIX gear
View Pricing and Purchasing Information 781779-35LabVIEW for LEGO MINDSTORMS, English8 - 13SGD 145.00 781779-3525LabVIEW for LEGO MINDSTORMS Site License, English8 - 13SGD 834.00 781779-3512LabVIEW for LEGO MINDSTORMS, Japanese8 - 13SGD 145.00 781779-352512LabVIEW for LEGO MINDSTORMS Site License, Japanese8 - 13SGD 834.00It would seem 2020 is the ballpark time for a new intelligent brick. There may be updates to the EV3 package before then, but all those should be compatible with the current one.There have been some pictures of the new WeDo2 electrical parts: wedo2 - Google Search . WeDo2 is the first kit to use Power Functions 2 with a new 6-pin electrical plug standard that would eventually roll out across the consumer and educational Mindstorms and Power Functions kits. It remains to be seen what interfacing leads the LEGO company will produce to ensure backward compatibility for PF, 9V, NXT/EV3 or other earlier products, at least so that their actuators could be driven from new control devices.
It appears the plugs would not be stackable, though that is no problem for the Mindstorms product line as that uses point-to-point connections. Power Functions currently allows plugs to be stacked, to drive multiple devices from one output, so that could be a problem unless further provision is announced. To drive multiple devices in Mindstorms, one uses a multiplexer.If you are experimenting with AI in the next 4 years then go for the EV3. AI would be based more within the intelligent brick than in the sensors and actuators; as long as you have some that are compatible with the unit (i.e. the EV3 consumer or educational kit) then you will have what you need. Individual devices are available to add to the kits. There will be EV3 sensors and actuators still available for a few years after any new unit is released because it takes time for educational users to move up to the latest standard; upgrading is not cheap for a class of 20! David Eaton is right about the trend so far, from LEGO, regarding Mindstorms.