This sketch is used by Exercise: A4988 Stepper Motor Driver.
Full Source Code
The full code is all in one file StepperSweep.ino.
// StepperSweep - move a stepper motor at different rates // // Copyright (c) 2016, Garth Zeglin. All rights reserved. Licensed under the // terms of the BSD 3-clause license as included in LICENSE. // // This program assumes that: // // 1. A A4988 stepper motor driver is connected to pins 2 and 3. // 2. A control potentiometer can vary the voltage on A0. // 3. The serial console on the Arduino IDE is set to 9600 baud communications speed. // ================================================================================ // Define constant values and global variables. // Define the pin numbers on which the outputs are generated. #define DIR_PIN 2 // The direction pin controls the direction of stepper motor rotation. #define STEP_PIN 3 // Each pulse on the STEP pin moves the stepper motor one angular unit. #define ENABLE_PIN 4 // Optional control of the driver power. // Alternate definitions for the Protoneer CNC Shield board X axis. // #define DIR_PIN 5 // #define STEP_PIN 2 // #define ENABLE_PIN 8 // ================================================================================ // Configure the hardware once after booting up. This runs once after pressing // reset or powering up the board. void setup(void) { // Initialize the stepper driver control pins to output drive mode. pinMode(DIR_PIN, OUTPUT); pinMode(STEP_PIN, OUTPUT); pinMode(ENABLE_PIN, OUTPUT); // Drive the /ENABLE pin low to keep the motor always energized. digitalWrite(ENABLE_PIN, LOW); // Initialize the serial UART at 9600 bits per second. Serial.begin(9600); } /****************************************************************/ /// Rotate the stepper motor a specified distance at constant speed. It does /// not return until the motion is complete, e.g. it 'blocks' for the duration. /// /// \param steps angular distance to move; the sign determines the direction, /// but the precise angle depends upon the driver microstepping /// configuration and type of motor. /// /// \param speed speed in steps/second void rotate_stepper(int steps, float speed) { // Configure the direction pin on the stepper motor driver based on the sign // of the displacement. int dir = (steps > 0)? HIGH:LOW; digitalWrite(DIR_PIN, dir); // Find the positive number of steps pulses to emit. int pulses = abs(steps); // Compute a delay time in microseconds controlling the duration of each half // of the step cycle. // microseconds/half-step = (1000000 microseconds/second) * (1 step/2 half-steps) / (steps/second) unsigned long wait_time = 500000/speed; // The delayMicroseconds() function cannot wait more than 16.383ms, so the // total delay is separated into millisecond and microsecond components. This // increases the range of speeds this function can handle. unsigned int msec = wait_time / 1000; unsigned int usec = wait_time - (1000*msec); // Print a status message to the console. Serial.print("Beginning rotation of "); Serial.print(steps); Serial.print(" steps with delay interval of "); Serial.print(msec); Serial.print(" milliseconds, "); Serial.print(usec); Serial.print(" microseconds.\n"); // Loop for the given number of step cycles. The driver will change outputs // on the rising edge of the step signal so short pulses would work fine, but // this produces a square wave for easier visualization on a scope. for(int i = 0; i < pulses; i++) { digitalWrite(STEP_PIN, HIGH); if (msec > 0) delay(msec); if (usec > 0) delayMicroseconds(usec); digitalWrite(STEP_PIN, LOW); if (msec > 0) delay(msec); if (usec > 0) delayMicroseconds(usec); } } // ================================================================================
Read more: Arduino Sketch Stepper Sweep