org.kjkoster.wedo.bricks.Tilt Maven / Gradle / Ivy
package org.kjkoster.wedo.bricks;
import static java.lang.String.format;
import static org.kjkoster.wedo.bricks.Tilt.Direction.BACKWARD;
import static org.kjkoster.wedo.bricks.Tilt.Direction.FORWARD;
import static org.kjkoster.wedo.bricks.Tilt.Direction.LEFT;
import static org.kjkoster.wedo.bricks.Tilt.Direction.NO_TILT;
import static org.kjkoster.wedo.bricks.Tilt.Direction.RIGHT;
import lombok.Value;
/**
* The representation of a single sample from a tilt sensor. These directions
* are taken with the wire of the sensor facing towards you.
*
* The tilt sensor does not tell us a whole lot when it is not slightly tilted.
* I chose to lump all of those under NO_TILT rather than calling
* it flat. The same value comes out when the sensor is placed on its side or
* straight up.
*
* @author Kees Jan Koster <[email protected]>
*/
@Value
public class Tilt {
private final byte value;
/**
* The tilt directions.
*/
public enum Direction {
/**
* backwards tilt.
*/
BACKWARD,
/**
* Forward tilt.
*/
FORWARD,
/**
* Left tilt.
*/
LEFT,
/**
* Right tilt.
*/
RIGHT,
/**
* Flat, upright or on its side, no way to tell.
*/
NO_TILT
}
/**
* Find the tilt direction, if one can be determined.
*
* @return The tilt direction.
*/
public Direction getDirection() {
final int tilt = (value & 0xff);
if (tilt < 4) {
throw new IllegalStateException(format(
"motor interference on tilt sensor (value 0x%02x)", value));
}
if (tilt > 10 && tilt < 40) {
return BACKWARD;
}
if (tilt > 60 && tilt < 90) {
return RIGHT;
}
if (tilt > 117 && tilt < 140) {
return NO_TILT;
}
if (tilt > 151 && tilt < 190) {
return FORWARD;
}
if (tilt > 203 && tilt < 240) {
return LEFT;
}
throw new IllegalArgumentException(
format("unknown tilt value 0x%02x", value));
}
}