NXTKit

NXTKit is a native (10.6+) Cocoa framework for talking with Lego NXT devices. Communication over both Bluetooth and USB is supported. To enforce a clean architecture, NXTKit is built on top of DeviceKit, thus separating transport communication details from higher-level functionality. Both Garbage Collected and non-Garbage Collected environments are supported.

Basic Usage

1. Check if a NXT brick is connected via USB. The MRUSBDeviceEntry class abstracts much of this. If a USB device can't be found, display an instance of IOBluetoothDeviceSelectorController (part of the IOBluetoothUI framework).
2. Construct a new MRBluetoothDeviceTransport or MRUSBDeviceTransport. Bluetooth should only be used when wireless connectivity is key or when USB isn't available, considering it uses more power.
3. Initialize an instance of MRNXTDevice with the device transport created in the previous step. Register yourself as a delegate of the device, and call - open: .
4. Once a Bluetooth or USB connection is established, you can enqueue subclasses of MRNXTCommand onto the device's work queue. If the passed response block is not NULL, an instance of MRNXTResponse will be provided in the callback block. Commands execute serially in FIFO order.

Example

NSArray *usbDevices = [MRUSBDeviceEntry matchingDevicesForProductID:0x2 vendorID:0x694];

if ([usbDevices count]) {
    // setup USB transport
    return;
}

// else setup Bluetooth transport

IOBluetoothDevice *device = ... ; /* returned from IOBluetoothDeviceSelectorController */

MRBluetoothDeviceTransport *transport = [[MRBluetoothDeviceTransport alloc]
                                                initWithBluetoothDevice:device];

nxtDevice = [[MRNXTDevice alloc] initWithTransport:transport];
[transport release];

[nxtDevice setDelegate:self];

if (![nxtDevice open:&error]) {
    // ... handle error
}

...

- (void)deviceDidOpen:(MRDevice *)aDevice {
    [self playSound];
}

- (void)playSound {
    MRNXTPlaySoundFileCommand *comm = [[MRNXTPlaySoundFileCommand alloc] init];
    comm.loop = NO;
    comm.filename = @"Woops.rso";
    
    [nxtDevice enqueueCommand:comm responseBlock:^(MRNXTResponse *response) {
        // work with response, check status, etc ...
    }];
    
    [comm release];
}

See the NXT-Browser project for a full, working sample that utilizes NXTKit.

About Filenames

All filenames on the NXT can have a maximum length of 19 characters (15.3), and will be truncated when necessary. The following wildcards are also accepted:

- Filename.Extension
- *.(Extension)
- Filename.*
- *.*