com.diozero.devices.ServoController Maven / Gradle / Ivy
The newest version!
package com.diozero.devices;
/*
* #%L
* Organisation: diozero
* Project: diozero - Core
* Filename: ServoController.java
*
* This file is part of the diozero project. More information about this project
* can be found at https://www.diozero.com/.
* %%
* Copyright (C) 2016 - 2024 diozero
* %%
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
* #L%
*/
import java.util.Objects;
import com.diozero.api.ServoDevice;
import com.diozero.api.ServoTrim;
/**
* A "wrapper" around the PCA9685 PWM controller: the main purpose is to prevent re-use of a previously allocated PWM
* channel.
*
* NOTEL The servo creation allows for setting the initial angle of the servo (aka `initialPulseWidthUs`). This
* is intended to prevent the servo from "jumping" to the default position when the servo is first powered on.
*
*/
public class ServoController implements AutoCloseable {
private final PCA9685 pwmController;
private final ServoDevice[] servos = new ServoDevice[16];
/**
* Default constructor. Uses the default PCA9685 controller.
*/
public ServoController() {
this(new PCA9685());
}
/**
* Constructor.
*
* @param controller the PCA9685 controller to use
*/
public ServoController(PCA9685 controller) {
pwmController = controller;
}
// implement singleton pattern
private static ServoController instance;
/**
* Get the singleton default instance of the ServoController.
*
* @return the default ServoController
*/
public static synchronized ServoController getInstance() {
if (instance == null) {
instance = new ServoController();
}
return instance;
}
@Override
public void close() throws Exception {
pwmController.close();
}
/**
* Get a ServoDevice for the specified channel. If the channel has not been used before, a new ServoDevice will be
* created. If the channel has been used before, the existing ServoDevice will be returned. This will use the default
* trim and the initial angle should be 90 degrees.
*
* @param servoNumber 0-15
* @return the appropriate ServoDevice
*/
public ServoDevice getServo(int servoNumber) {
return createOrGetServo(servoNumber, ServoTrim.DEFAULT, null);
}
/**
* Get a ServoDevice for the specified servo. If the servo has not been used before, a new ServoDevice will be
* created. If it has been used before, the existing ServoDevice will be returned. This will use the default trim.
*
* @param servoNumber 0-15
* @param startAngle the initial angle
* @return the appropriate ServoDevice
*/
public ServoDevice getServo(int servoNumber, int startAngle) {
return getServo(servoNumber, ServoTrim.DEFAULT, startAngle);
}
/**
* Get a ServoDevice for the specified servo. If the servo has not been used before, a new ServoDevice will be
* created. If it has been used before, the existing ServoDevice will be returned. The initial angle should
* be 90 degrees.
*
* @param servoNumber 0-15
* @param trim Servo trim
* @return the appropriate ServoDevice
*/
public ServoDevice getServo(int servoNumber, ServoTrim trim) {
return createOrGetServo(servoNumber, trim, null);
}
/**
* Get a ServoDevice for the specified servo. If the servo has not been used before, a new ServoDevice will be
* created. If it has been used before, the existing ServoDevice will be returned.
*
* NOTE: {@code trim} and {@code startAngle} will only be applied on device creation.
*
*
* @param servoNumber 0-15
* @param trim Servo trim
* @param startAngle the initial angle
* @return the appropriate ServoDevice
*/
public ServoDevice getServo(int servoNumber, ServoTrim trim, int startAngle) {
return createOrGetServo(servoNumber, trim, trim.convertAngleToPulseWidthUs(startAngle));
}
private synchronized ServoDevice createOrGetServo(int servoNumber, ServoTrim trim, Integer initialPulseWidthUs) {
Objects.checkIndex(servoNumber, 16);
if (servos[servoNumber] == null) {
servos[servoNumber] = new ServoDevice.Builder(servoNumber)
.setDeviceFactory(pwmController)
.setTrim(trim)
.setFrequency(pwmController.getBoardPwmFrequency())
.setInitialPulseWidthUs(initialPulseWidthUs)
.build();
}
return servos[servoNumber];
}
}