Controlling the Hardware (LCD, Buttons and Sound)

Controlling the Hardware(LCD, Buttons and Sound) Fall, 2008

Presentaion Schedule

LCD • LCD (Liquid Crystal Display) • text mode and graphics mode. • Text LCD methods • NXT LCD screen is 16 characters wide and eight characters deep. • x ranges from 0 to 15, and y from 0 to 7. • public static drawString(String str, int x, int y); • a string of text to the LCD screen starting at text co-ordinate • (1 character == 8 pixels) • drawString(String str, int x, int y, boolean invert); • inverting the text drawing white characters on black background. • public static drawInt(int i, int x, int y); • an integer starting at co-ordinate (x,y). left aligned • public static drawInt(int i, int places, int x, int y); • right-aligns the integer • the number of characters indicated by places

LCD • drawChar(char c, int x, int y, boolean invert); • a character at text co-ordinate (x, y) with optional inversion of the character. • public static clear(); • Clears the display import lejos.nxt.*; import java.io.*; public class LCDTest { public static void main (String[] args) throws Exception { LCD.drawString("F_memory:", 0, 0); LCD.drawString("SCREEN_WIDTH:", 0, 8, true); LCD.drawString("SCREEN_HEIGHT:", 0, 15, true); LCD.drawInt((int) Runtime.getRuntime().freeMemory(), 4, 11, 0); LCD.drawInt(LCD.SCREEN_WIDTH, 3, 12, 1); LCD.drawInt(LCD.SCREEN_HEIGHT, 3, 12, 2); Thread.sleep(10000); } }

Buttons • Buttons • The NXT buttons are accessed by static fields: • Button.ENTER • Button.ESCAPE • Button.LEFT • Button.RIGHT • public final boolean isPressed(); • Check if the button is pressed.

Buttons : Example 1 import lejos.nxt.*; public class ButtonPresses { public static void main (String[] args) throws Exception { while (true) { LCD.clear(); if (Button.ENTER.isPressed()) { LCD.drawString("ENTER",0,0); Thread.sleep(1000); } if (Button.ESCAPE.isPressed()) { LCD.drawString("ESCAPE",0,0); Thread.sleep(1000); break; } if (Button.LEFT.isPressed()) { LCD.drawString("LEFT",0,0); Thread.sleep(1000); } if (Button.RIGHT.isPressed()) { LCD.drawString("RIGHT",0,0); Thread.sleep(1000); } } } }

Buttons • void waitForPressAndRelease() • Wait until the button is released • static int waitForPress() • wait for some button to be pressed • returns the id of the button that is pressed. • public static int readButtons() • 0x01 (ENTER button pressed), • 0x02 (LEFT button pressed), • 0x04 (RIGHT button pressed), • 0x08 (ESCAPE button pressed). • If all buttons are released, this method returns 0. • public void addButtonListener(ButtonListener aListener) • Adds a listener of button events. • Each button can serve at most 4 listeners.

Buttons : Example 2 import lejos.nxt.*; public class ButtonTest { public static void main (String[] args)throws Exception { int bid; Button.ENTER.waitForPressAndRelease(); LCD.drawString("Finished", 3, 4); Thread.sleep(2000); bid=Button.ESCAPE.waitForPress(); LCD.drawString("ESCAPE...", 3, 5); LCD.drawInt(bid, 11, 5); Thread.sleep(2000); bid=LCD.readButtons(); LCD.drawInt(bid, 11, 7); Thread.sleep(2000); } }

Sound • Sound • public static playTone(int aFrequency, int aDuration, int aVolume); • aFrequency - The frequency of the tone in Hertz (Hz). • aDuration - The duration of the tone, in milliseconds. • (aVolume) : The volume of the playback 100 corresponds to 100%

Sound: Example1 import lejos.nxt.*; public class Tune { // NOTE: This tune was generated from a midi using Guy // Truffelli's Brick Music Studio www.aga.it/~guy/lego private static final short [] note = { 2349,115, 0,5, 1760,165, 0,35, 1760,28, 0,13, 1976,23, 0,18, 1760,18, 0,23, 1568,15, 0,25, 1480,103, 0,18, 1175,180, 0,20, 1760,18, 0,23, 1976,20, 0,20, 1760,15, 0,25, 1568,15, 0,25, 2217,98, 0,23, 1760,88, 0,33, 1760,75, 0,5, 1760,20, 0,20, 1760,20, 0,20, 1976,18, 0,23, 1760,18, 0,23, 2217,225, 0,15, 2217,218}; public static void main(String [] args) { for(int i=0;i<note.length; i+=2) { final short w = note[i+1]; final int n = note[i]; if (n != 0) Sound.playTone(n, w*10); try { Thread.sleep(w*10); } catch (InterruptedException e) {} } } }

Sound • public static void systemSound (boolean aQueued, int aCode); • aQueued parameter is ignored on the NXT. • code = 0 : Short beep  public static void beep(); • code = 1 : Double beep public static void twoBeeps(); • code = 2 : Descending arpeggio  public static void beepSequence(); • code = 3 : Ascending arpeggio  public static void beepSequenceUp(); • code = 4 : Long, low buzz public static void buzz(); • public static void pause(int t); • produce a rest when playing a tune:

Sound • public static int playSample(File file, intvol) • play 8-bit WAV files. • vol: volume control (0 ~ 100) • Upload a WAV File to NXT • Command prompt: nxtbrowse • Connect  Upload file • Select a WAV File • ringin.wav, ringout.wav

Sound: Example2 import lejos.nxt.*; import java.io.*; public class SoundSample { static File f1,f2; public static void main(String [] options) throws Exception { f1 = new File("ringin.wav"); f2 = new File("ringout.wav"); LCD.drawString("Play a WAV file",0,0); while(true) { Sound.playSample(f1,100); Thread.sleep(1500); if (Button.readButtons()>0) break; } Sound.playSample(f2,100); } }

Reference • Reference • http://www.bartneck.de/2008/03/04/java-lego-nxt-eclipse-tutorial/ • http://www.seas.upenn.edu/~pfpcse/NXT/nxtjavatutorial.html • http://lejos-osek.sourceforge.net/nxt2nxt.htm • http://lejos.sourceforge.net/ • http://www.juanantonio.info/jab_cms.php?id=206 • http://lejos.sourceforge.net/nxt/nxj/api/index.html

Controlling the Hardware (LCD, Buttons and Sound)