//加一顆 LED 測試 Uno 是否能正常工作

setup(){

    pinMode(6, OUTPUT);

}

loop(){

    digitalWrite(6, HIGH);

    delay(1000);

    digitalWrite(6, LOW);

    delay(1000);

}

舵機藉由回饋訊號控制，以 SG90S 為例，其內部有一個可變電阻，電阻值會根據直流馬達轉動而改變

改變的電阻值會產生相對應直流電壓，與外部脈波信號產生的相對應直流電壓的壓差再回饋到直流馬達上

當二者電壓差值為 0 時，舵機停止

基本驅動的方式為輸入一個 50Hz，脈波範圍從 1.0ms 到 2.0ms  的 PWM 值

依據規格書上說明，50Hz 1.5ms 的脈波會讓舵機位置置中，1ms 的脈波會讓舵機 all the way left，反之 2ms 的脈波會讓舵機 all the way right

使用上會以函式庫為主

要特別注意的是當發生舵機堵轉(因為某種因素無法轉到要求的位置)時，會導致電流異常持續升高或減速齒輪空轉磨齒損壞電機

SG90S 規格

重量：9g

尺寸：23*12.2*29mm

工作電壓：4.8V(~5V)

轉矩：1.8kg-cm，當工作電壓為4.8V時

運轉速度：0.1秒 ∕ 60度 ，當工作電壓為4.8V時

脈衝寬度範圍：500~2400µs  

死頻帶寬度（dead band width）：10µs

#include <Servo.h>

Servo myservo;

int pos = 0;

void setup(){

    myservo.attach(9);

}

void loop(){

    for(pos = 20; pos <= 110; pos += 1){

        myservo.write(pos);

        delay(10);

    }

    for(pos = 110; pos >= 20; pos += -1){

        myservo.write(pos);

        delay(10);

    }

} 

使用 uln2003 IC 來做驅動 28BYJ-48, 5V DC，規格如下：

• 工作電壓： 5~12V DC

• 轉一圈步數：5.625度/64 (搭配 1/64減速齒輪達到 4096 脈波數轉一圈)

• 每分鐘圈數：80 RPM(Revolution per minute)

• 重量：37 公克

int motorPin1 = 8;

int motorPin2 = 9;

int motorPin3 = 10;

int motorPin4 = 11;

int motorSpeed = 5;

// 1相激磁

void clockwise3() {

// 1

    digitalWrite(motorPin4, HIGH);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin1, LOW);

    delay(motorSpeed);

// 2

    digitalWrite(motorPin4, LOW);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin1, LOW);

    delay(motorSpeed);

// 3

    digitalWrite(motorPin4, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin1, LOW);

    delay(motorSpeed);

// 4

    digitalWrite(motorPin4, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin1, HIGH);

    delay(motorSpeed);

}

// 1-2相激磁

void counterclockwise (){

// 1

    digitalWrite(motorPin1, HIGH);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin4, LOW);

    delay(motorSpeed);

// 2

    digitalWrite(motorPin1, HIGH);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin4, LOW);

    delay (motorSpeed);

// 3

    digitalWrite(motorPin1, LOW);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin4, LOW);

    delay(motorSpeed);

// 4

    digitalWrite(motorPin1, LOW);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin4, LOW);

    delay(motorSpeed);

// 5

    digitalWrite(motorPin1, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin4, LOW);

    delay(motorSpeed);

// 6

    digitalWrite(motorPin1, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin4, HIGH);

    delay (motorSpeed);

// 7

    digitalWrite(motorPin1, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin4, HIGH);

    delay(motorSpeed);

// 8

    digitalWrite(motorPin1, HIGH);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin4, HIGH);

    delay(motorSpeed);

}

//2相激磁

void clockwise2() {

// 1

    digitalWrite(motorPin4, HIGH);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin1, LOW);

    delay(motorSpeed);

// 2

    digitalWrite(motorPin4, LOW);

    digitalWrite(motorPin3, HIGH);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin1, LOW);

    delay(motorSpeed);

// 3

    digitalWrite(motorPin4, LOW);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin2, HIGH);

    digitalWrite(motorPin1, HIGH);

    delay(motorSpeed);

// 4

    digitalWrite(motorPin4, HIGH);

    digitalWrite(motorPin3, LOW);

    digitalWrite(motorPin2, LOW);

    digitalWrite(motorPin1, HIGH);

    delay(motorSpeed);

}

#include <Stepper.h>

Stepper stepper(64, 8,9,10,11);

//轉一圈為64步 (360/5.625 deg)，定義8,9,10,11為輸出腳位

void setup(){

    //將馬達的速度設定成80RPM

    stepper.setSpeed(80); 

}

void loop(){

    stepper.step(256);//正半圈

    delay(1000);

    stepper.step(-256);//反半圈

    delay(1000);

    stepper.step(512);//正1圈

    delay(1000);

    stepper.step(-512);//反1圈

    delay(1000);

}

發現步進馬達不會反向轉，問題出在官方的函式庫驅動的順序

修改 libraries\Stepper\src\Stepper.cpp 約 186 行

將

if (this->pin_count == 4) {

    switch (thisStep) {

      case 0:    // 1010

      digitalWrite(motor_pin_1, HIGH);

      digitalWrite(motor_pin_2, LOW);

      digitalWrite(motor_pin_3, HIGH);

      digitalWrite(motor_pin_4, LOW);

      break;

      case 1:    // 0110

      digitalWrite(motor_pin_1, LOW);

      digitalWrite(motor_pin_2, HIGH);

      digitalWrite(motor_pin_3, HIGH);

      digitalWrite(motor_pin_4, LOW);

      break;

      case 2:    //0101

      digitalWrite(motor_pin_1, LOW);

      digitalWrite(motor_pin_2, HIGH);

      digitalWrite(motor_pin_3, LOW);

      digitalWrite(motor_pin_4, HIGH);

      break;

      case 3:    //1001

      digitalWrite(motor_pin_1, HIGH);

      digitalWrite(motor_pin_2, LOW);

      digitalWrite(motor_pin_3, LOW);

      digitalWrite(motor_pin_4, HIGH);

      break;

    } 

改成

if (this->pin_count == 4) {

    switch (thisStep) {

      case 0:    // 0011

      digitalWrite(motor_pin_1, LOW);

      digitalWrite(motor_pin_2, LOW);

      digitalWrite(motor_pin_3, HIGH);

      digitalWrite(motor_pin_4, HIGH);

      break;

      case 1:    // 0110

      digitalWrite(motor_pin_1, LOW);

      digitalWrite(motor_pin_2, HIGH);

      digitalWrite(motor_pin_3, HIGH);

      digitalWrite(motor_pin_4, LOW);

      break;

      case 2:    //1100

      digitalWrite(motor_pin_1, HIGH);

      digitalWrite(motor_pin_2, HIGH);

      digitalWrite(motor_pin_3, LOW);

      digitalWrite(motor_pin_4, LOW);

      break;

      case 3:    //1001

      digitalWrite(motor_pin_1, HIGH);

      digitalWrite(motor_pin_2, LOW);

      digitalWrite(motor_pin_3, LOW);

      digitalWrite(motor_pin_4, HIGH);

      break;

    }