Package com.crossbotics.ftchelper.hardware

Class ServoSetup

java.lang.Object
com.crossbotics.ftchelper.hardware.ServoSetup
public final class ServoSetup extends Object
Sets up a servo in one readable chain.

A servo is a small motor that turns to a position you choose (0 to 1) and holds it there. 


 Servo claw = ServoSetup.get(hardwareMap, "claw")
         .reversed()
         .range(0.20, 0.75)   // 0 now means 0.20 and 1 means 0.75
         .done();

This does NOT move the servo. A servo moves the first time you set a position.

How far 0 to 1 turns it. The hub tells a servo where to go with a pulse: 600 microseconds (us) for position 0 and 2400 us for 1 (the FTC SDK's normal range). Most FTC servos can take 500 to 2500 us, so the normal range leaves a little of their turn unused: a goBILDA 2000 servo (300 degrees over 500-2500 us) turns 270 degrees over 0 to 1. fullRange() widens the pulse to 500-2500 us, so 0 to 1 turns it all 300 degrees. Docs: docs/modules/hardware.md#full-range.

Each step hands back the same ServoSetup (return this) so the next step can follow. Tutorial 02 (docs/tutorials/02-motors-and-servos.md) shows servos in a full program. Docs: docs/modules/hardware.md

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final double
    FULL_PULSE_HIGH_US
    The pulse for position 1 with fullRange().
    static final double
    FULL_PULSE_LOW_US
    The pulse for position 0 with fullRange(): what goBILDA, REV and Axon servos accept.
    static final double
    SDK_PULSE_HIGH_US
    The FTC SDK's normal pulse for position 1, microseconds (PwmControl.PwmRange.usPulseUpperDefault).
    static final double
    SDK_PULSE_LOW_US
    The FTC SDK's normal pulse for position 0, microseconds (PwmControl.PwmRange.usPulseLowerDefault).

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    checkPulse(double lowUs, double highUs)
    Checks a pulse range: 100 to 3000 microseconds, low below high.
    com.qualcomm.robotcore.hardware.Servo
    done()
    Gives you the servo.
    ServoSetup
    fullRange()
    Uses the servo's whole turn: positions 0 to 1 send 500 to 2500 microseconds instead of the SDK's normal 600 to 2400.
    static ServoSetup
    get(com.qualcomm.robotcore.hardware.HardwareMap hardwareMap, String name)
    Starts the setup for a servo in the configuration.
    static ServoSetup
    of(com.qualcomm.robotcore.hardware.Servo servo)
    Starts the setup for a servo you already have.
    ServoSetup
    pulseRange(double lowUs, double highUs)
    Sets the pulse the hub sends for positions 0 and 1 (see fullRange() for the usual one).
    ServoSetup
    range(double min, double max)
    Limits the servo to part of its travel.
    ServoSetup
    reversed()
    Position 0 and 1 swap ends.
    static boolean
    setPulseRange(com.qualcomm.robotcore.hardware.Servo servo, double lowUs, double highUs)
    Sets a servo's pulse range if it can (a servo on a REV Control or Expansion Hub, or a Servo Hub, can: it is a PwmControl).

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • SDK_PULSE_LOW_US

      public static final double SDK_PULSE_LOW_US
      The FTC SDK's normal pulse for position 0, microseconds (PwmControl.PwmRange.usPulseLowerDefault).
      See Also:

    • SDK_PULSE_HIGH_US

      public static final double SDK_PULSE_HIGH_US
      The FTC SDK's normal pulse for position 1, microseconds (PwmControl.PwmRange.usPulseUpperDefault).
      See Also:

    • FULL_PULSE_LOW_US

      public static final double FULL_PULSE_LOW_US
      The pulse for position 0 with fullRange(): what goBILDA, REV and Axon servos accept.
      See Also:

    • FULL_PULSE_HIGH_US

      public static final double FULL_PULSE_HIGH_US
      The pulse for position 1 with fullRange().
      See Also:

  • Method Details

    • get

      public static ServoSetup get(com.qualcomm.robotcore.hardware.HardwareMap hardwareMap, String name)
      Starts the setup for a servo in the configuration.
      Parameters:
      hardwareMap - the OpMode's hardwareMap
      name - the servo's configuration name
      Returns:
      the start of the chain
      Throws:
      IllegalArgumentException - with the list of real servo names if the name is wrong

    • of

      public static ServoSetup of(com.qualcomm.robotcore.hardware.Servo servo)
      Starts the setup for a servo you already have.
      Parameters:
      servo - the servo to set up
      Returns:
      the start of the chain

    • reversed

      public ServoSetup reversed()
      Position 0 and 1 swap ends. Use when a servo is mounted mirrored.

    • range

      public ServoSetup range(double min, double max)
      Limits the servo to part of its travel. After this, position 0 means min and position 1 means max. Use it so code can never drive the servo into the frame.
      Parameters:
      min - 0 to 1, the real position used for 0
      max - 0 to 1, the real position used for 1 (must be bigger than min)

    • fullRange

      public ServoSetup fullRange()
      Uses the servo's whole turn: positions 0 to 1 send 500 to 2500 microseconds instead of the SDK's normal 600 to 2400. A goBILDA 2000 servo then turns 300 degrees over 0 to 1 instead of 270. Do it BEFORE you measure positions (the Servo Finder has the same switch): the same position number points somewhere else after the change. A servo that cannot change its pulse (not on a REV hub) keeps the normal range: check setPulseRange(com.qualcomm.robotcore.hardware.Servo, double, double)'s answer if you need to know. 
      
 Servo wrist = ServoSetup.get(hardwareMap, "wrist").fullRange().done();
      Returns:
      this setup, for the next step

    • pulseRange

      public ServoSetup pulseRange(double lowUs, double highUs)
      Sets the pulse the hub sends for positions 0 and 1 (see fullRange() for the usual one).
      Parameters:
      lowUs - microseconds for position 0, e.g. 500 (100 to 3000)
      highUs - microseconds for position 1, e.g. 2500 (more than lowUs, at most 3000)
      Returns:
      this setup, for the next step
      Throws:
      IllegalArgumentException - for numbers outside those ranges

    • setPulseRange

      public static boolean setPulseRange(com.qualcomm.robotcore.hardware.Servo servo, double lowUs, double highUs)
      Sets a servo's pulse range if it can (a servo on a REV Control or Expansion Hub, or a Servo Hub, can: it is a PwmControl). Does not move it.
      Parameters:
      servo - the servo
      lowUs - microseconds for position 0 (100 to 3000)
      highUs - microseconds for position 1 (more than lowUs, at most 3000)
      Returns:
      true if it was set; false if this servo cannot change its pulse (it keeps its range)
      Throws:
      IllegalArgumentException - for numbers outside those ranges

    • checkPulse

      public static void checkPulse(double lowUs, double highUs)
      Checks a pulse range: 100 to 3000 microseconds, low below high.
      Parameters:
      lowUs - microseconds for position 0
      highUs - microseconds for position 1
      Throws:
      IllegalArgumentException - when they are not

    • done

      public com.qualcomm.robotcore.hardware.Servo done()
      Gives you the servo. Always end the chain with this.
      Returns:
      the servo, set up (it has not moved yet)