challenge-bot.com Git - 3501/stronghold-2016/blob - src/org/usfirst/frc/team3501/robot/sensors/Photogate.java

   1 package org.usfirst.frc.team3501.robot.sensors;
   2
   3 import edu.wpi.first.wpilibj.AnalogInput;
   4
   5 /***
   6  * The photogate is a pair of IR LED and phototransistor sensor that uses a
   7  * reflective method to sense the presence of the boulder within the robot's
   8  * shooting chamber. This class specifically checks for the ball's presence
   9  * using a threshold of voltages outputted from the phototransistor.
  10  *
  11  * @author niyatisriram
  12  */
  13 public class Photogate extends AnalogInput {
  14
  15   private double threshold = 1.8;
  16
  17   /***
  18    * The constructor inputs the channel of the transistor and the threshold
  19    * value.
  20    * The threshold is a specific value, representing the outputted voltage of
  21    * the phototransistor. This value will be somewhere within the range [0,
  22    * 4095] Find the value by testing and finding an average value for which the
  23    * ball is present when the output is greater, and absent when the output is
  24    * less.
  25    */
  26   public Photogate(int channel, int threshold) {
  27     super(channel);
  28     this.threshold = threshold;
  29   }
  30
  31   /***
  32    * @return whether the ball is present or not
  33    */
  34   public boolean isBallPresent() {
  35     if (this.getVoltage() > threshold)
  36       return true;
  37     else
  38       return false;
  39
  40   }
  41
  42   /***
  43    * @param threshold
  44    *          (range [0, 4095])
  45    */
  46   public void setThreshold(int threshold) {
  47     this.threshold = threshold;
  48   }
  49 }