/*
* #%L
* **********************************************************************
* ORGANIZATION : Pi4J
* PROJECT : Pi4J :: Java Examples
* FILENAME : StepperMotorGpioExample.java
*
* This file is part of the Pi4J project. More information about
* this project can be found here: http://www.pi4j.com/
* **********************************************************************
* %%
* Copyright (C) 2012 - 2013 Pi4J
* %%
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
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* #L%
*/
import com.pi4j.component.motor.impl.GpioStepperMotorComponent;
import com.pi4j.io.gpio.GpioController;
import com.pi4j.io.gpio.GpioFactory;
import com.pi4j.io.gpio.GpioPinDigitalOutput;
import com.pi4j.io.gpio.PinState;
import com.pi4j.io.gpio.RaspiPin;
/**
* This example code demonstrates how to control a stepper motor
* using the GPIO pins on the Raspberry Pi.
*
* @author Robert Savage
*/
public class StepperMotorGpioExample {
public static void main(String[] args) throws InterruptedException {
System.out.println("<--Pi4J--> GPIO Stepper Motor Example ... started.");
// create gpio controller
final GpioController gpio = GpioFactory.getInstance();
// provision gpio pins #00 to #03 as output pins and ensure in LOW state
final GpioPinDigitalOutput[] pins = {
gpio.provisionDigitalOutputPin(RaspiPin.GPIO_00, PinState.LOW),
gpio.provisionDigitalOutputPin(RaspiPin.GPIO_01, PinState.LOW),
gpio.provisionDigitalOutputPin(RaspiPin.GPIO_02, PinState.LOW),
gpio.provisionDigitalOutputPin(RaspiPin.GPIO_03, PinState.LOW)};
// this will ensure that the motor is stopped when the program terminates
gpio.setShutdownOptions(true, PinState.LOW, pins);
// create motor component
GpioStepperMotorComponent motor = new GpioStepperMotorComponent(pins);
// @see http://www.lirtex.com/robotics/stepper-motor-controller-circuit/
// for additional details on stepping techniques
// create byte array to demonstrate a single-step sequencing
// (This is the most basic method, turning on a single electromagnet every time.
// This sequence requires the least amount of energy and generates the smoothest movement.)
byte[] single_step_sequence = new byte[4];
single_step_sequence[0] = (byte) 0b0001;
single_step_sequence[1] = (byte) 0b0010;
single_step_sequence[2] = (byte) 0b0100;
single_step_sequence[3] = (byte) 0b1000;
// create byte array to demonstrate a double-step sequencing
// (In this method two coils are turned on simultaneously. This method does not generate
// a smooth movement as the previous method, and it requires double the current, but as
// return it generates double the torque.)
byte[] double_step_sequence = new byte[4];
double_step_sequence[0] = (byte) 0b0011;
double_step_sequence[1] = (byte) 0b0110;
double_step_sequence[2] = (byte) 0b1100;
double_step_sequence[3] = (byte) 0b1001;
// create byte array to demonstrate a half-step sequencing
// (In this method two coils are turned on simultaneously. This method does not generate
// a smooth movement as the previous method, and it requires double the current, but as
// return it generates double the torque.)
byte[] half_step_sequence = new byte[8];
half_step_sequence[0] = (byte) 0b0001;
half_step_sequence[1] = (byte) 0b0011;
half_step_sequence[2] = (byte) 0b0010;
half_step_sequence[3] = (byte) 0b0110;
half_step_sequence[4] = (byte) 0b0100;
half_step_sequence[5] = (byte) 0b1100;
half_step_sequence[6] = (byte) 0b1000;
half_step_sequence[7] = (byte) 0b1001;
// define stepper parameters before attempting to control motor
// anything lower than 2 ms does not work for my sample motor using single step sequence
motor.setStepInterval(2);
motor.setStepSequence(single_step_sequence);
// There are 32 steps per revolution on my sample motor, and inside is a ~1/64 reduction gear set.
// Gear reduction is actually: (32/9)/(22/11)x(26/9)x(31/10)=63.683950617
// This means is that there are really 32*63.683950617 steps per revolution = 2037.88641975 ~ 2038 steps!
motor.setStepsPerRevolution(2038);
// test motor control : STEPPING FORWARD
System.out.println(" Motor FORWARD for 2038 steps.");
motor.step(2038);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : STEPPING REVERSE
System.out.println(" Motor REVERSE for 2038 steps.");
motor.step(-2038);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : ROTATE FORWARD
System.out.println(" Motor FORWARD for 2 revolutions.");
motor.rotate(2);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : ROTATE REVERSE
System.out.println(" Motor REVERSE for 2 revolutions.");
motor.rotate(-2);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : TIMED FORWARD
System.out.println(" Motor FORWARD for 5 seconds.");
motor.forward(5000);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : TIMED REVERSE
System.out.println(" Motor REVERSE for 5 seconds.");
motor.reverse(5000);
System.out.println(" Motor STOPPED for 2 seconds.");
Thread.sleep(2000);
// test motor control : ROTATE FORWARD with different timing and sequence
System.out.println(" Motor FORWARD with slower speed and higher torque for 1 revolution.");
motor.setStepSequence(double_step_sequence);
motor.setStepInterval(10);
motor.rotate(1);
System.out.println(" Motor STOPPED.");
// final stop to ensure no motor activity
motor.stop();
// stop all GPIO activity/threads by shutting down the GPIO controller
// (this method will forcefully shutdown all GPIO monitoring threads and scheduled tasks)
gpio.shutdown();
}
}