birt barcode open source The MINDSTORMS NXT in Font

Generation Denso QR Bar Code in Font The MINDSTORMS NXT

In particular, the NXT programmable brick shown in Figure 1-4 has a 32-bit microprocessor, 4 inputs, 3 outputs, Bluetooth communications, a speaker, and a 100x64 LCD display. Also, the NXT includes three powerful motors with built-in rotation sensors. The graphical programming language, NXT-G, is simple but complete enough to be quite usable.

Figure 1-4. The NXT programmable brick LEGO didn t just improve on the product; it went about improving the product launch as well. One hundred NXT kits were distributed months ahead of the major launch to a hand-selected group through the MINDSTORMS Developer Program (MDP) to work out any remaining issues. LEGO even provided detailed product documentation and SDKs well in advance. Aftermarket sensor manufacturers and software developers were able to have products available immediately, as opposed to months later for the RIS. There was only a small network of NXT hackers because the product was very capable right out of the box. Its programming language is quite usable; there s an extra input, three sophisticated motors, and more types of sensors; and it is well-documented. Not that there aren t ways to go beyond what comes in the MINDSTORMS NXT box LEGO couldn t possibly provide every sensor or actuator that could be used for building inventions, and that s where this book fits in. In 2009, LEGO freshened up the NXT kit with an improved NXT2 (see Figure 1-5). The NXT2 has enhancements to the software as well as a Color Sensor to replace the original monochrome Light Sensor. The second-generation kit no longer includes the Sound Sensor and it has a slight change in parts inventory to reflect the four new construction plans. The MINDSTORMS product continues to be

a very popular consumer item as well as a major tool in education. It has even been chosen as the computer for the FIRST LEGO League and FIRST Tech Challenge robotic competitions.

Figure 1-5. Steven Canvin, Marketing Manager, LEGO MINDSTORMS, holding the very first NXT 2.0 kit Photo courtesy of LEGO

Sensors provide feedback to a system telling it where it is or how it s doing. The NXT has several types of sensors designed specifically for it and backward compatibility to the old RCX sensors. All the sensors are well documented by LEGO, but we ll provide additional characteristics and show the internal construction of the sensors.

The original NXT came with five types of sensors:Touch, Light, Sound, Ultrasonic, and Rotation. The NXT Rotation Sensor is conveniently built into its motor so shaft position and speed are always available to NXT programs. Second-generation NXTs replaced the Light Sensor with one that could additionally discriminate color and eliminated the Sound Sensor entirely.

The NXT Touch Sensor is shown in Figure 1-6. A nice feature of the Touch Sensor is its cross-hole that allows you to connect the sensor operator directly to other assemblies.

Figure 1-6. NXT Touch Sensor Internally, the Touch Sensor is a printed circuit board (PCB) mounted push button and a connector, as seen in Figure 1-7. There s also a resistor in series with the switch so it won t create a dead short if it s accidentally connected to an output port.

The NXT Light Sensor includes a red light emitting diode (LED) light source that can be turned on and off from software (see Figures 1-8 and 1-9). The LED allows you to measure either the reflected LED light shining back from an object or the ambient light falling on the sensor.

Figure 1-8. NXT Light Sensor In Figure 1-9, you can see the LED, phototransistor, and connector mounted on the top of the PCB. All the small surface-mounted electronics are on the bottom of the board.