1. Decisions, Looping, and input sensors Mindstorms, Eclipse and Java

2. Decisions and Looping  So far, we can only execute a sequence of lines of code.  Decision control structures  Vary which lines of code to execute if something is true or false.  The IF statement  Looping control structures  Repeat code over and over again some number of times.  The WHILE loop

3. IF Statement The Java: if(condition){ // java code }

4. But what can the condition be?  Relational operators: ==equal to !=not equal to >greater than <less than >=greater than or equal to <=less than or equal to truealways true falsealways false

5. Example: int x = 5; if (x > 10){ LCD.drawString(“Hi”, 0, 0); } if(x <= 10){ LCD.drawString(“Bye”, 0, 0); } What is displayed on the LCD?

6. While The Java: while(condition){ // java code }

7. Example int y = 1; while (y <= 3){ LCD.drawString(“Hi”, 0, y); y = y + 1; } What is displayed on the LCD?

8. Using Input Sensors  The Mindstorms input sensors can return data that you can use in a condition to make a decision. Buttons  The Button class has four instances, accessed by static fields:  Button.ENTER  Button.ESCAPE  Button.LEFT  Button.RIGHT

9. Methods  waitForPress()  Returns an integer corresponding a button  ENTER: 1  LEFT:2  RIGHT:4  ESCAPE:8  waitForPressAndRelease()  Can be applied to any button  Example: Button.ENTER. waitForPressAndRelease();  isPressed()  Can be applied to any button  Returns true or false

10. Example Button Code while (true) { LCD.clear(); if (Button.ENTER.isPressed()) LCD.drawString("ENTER", 0, 0); if (Button.ESCAPE.isPressed()) LCD.drawString("ESCAPE", 0, 0); if (Button.LEFT.isPressed()) LCD.drawString("LEFT", 0, 0); if (Button.RIGHT.isPressed()) LCD.drawString("RIGHT", 0, 0); }

11. Sensing Touch  TouchSensor  isPressed()  Returns true if the button is pressed.  Needs to be plugged into one of the Sensor ports.  In your code, you will need to declare a new touch sensor, indicating which port it is plugged into: TouchSensor t = new TouchSensor(SensorPort.S1); Give it a name Indicate the port number

12. Sensor port 1 Example: Plug the touch senor in the port 1

13. Try this code: What is displayed on the LCD?

14. Sound Sensor  SoundSensor  Readvalue()  Returns a value in the range [0-100] corresponding to how much noise it hears.  Like the touch sensor it needs to be plugged into a sensor port and initialized

15. Try out this code What is displayed on the LCD?

16. This code uses sound to trigger a motor to rotate

17. The Ultra Sonic Distance Sensor  UltrasonicSensor  getDistance()  Returns the distance to an object in CM.  A value of 255 means no distance was detected  Maximum is about 170  Example Code:

18. Light Sensor  LightSensor  Sensor how much light in around the Mindstorm  readValue()  Returns the raw value  readNormalizedValue()  Returns a value in between 0 to 1023  setFloodLight(boolean)  Turn flood light on or off.

19. Light Sensor Example Code

20. Wrapping up…  Sound Object  Make the Mindstorm beep  beep()  twoBeeps()  beepSequence()  beepSequenceUp()  playTone(int aFrequency, int aDuration)  playSample(File aWAVfile)  playSample(File aWAVfile, int volume)  playNote(int[] inst,int freq, int len)

21. Wrapping up…  Battery  getVoltageMilliVolt()  getVoltage()  LCD  setPixel(int pixelValue, int x, int y);  Can be used to draw a single pixel (dot) on the LCD

22. Drawing a Parabola on LCD

23. Plot sound waves over a 2 second period. VERY COOL!!!!