Motor Speed Control with One Transistor

I will show you how control a motor's speed with one transistor and a personal PWM signal.

Oct 25, 2018

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26109 views

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5 respects

Components and supplies

DC motor (generic)

Rotary potentiometer (generic)

LED (generic)

Pushbutton switch 12mm

Breadboard (generic)

General Purpose Transistor NPN

Resistor 1k ohm

Arduino UNO

Resistor 221 ohm

Capacitor 100 µF

Elegoo Starter Kit

1N4007 – High Voltage, High Current Rated Diode

Apps and platforms

Arduino IDE

Project description

Code

Motor_Control

arduino

1//Control motor with PWM
2
3#define MOTOR 13
4#define LED_ON 5
5#define   LED_OFF 4
6
7//Button variables
8int button_state = 0;
9int last_button_state   = 1;
10
11//State of motor
12bool motor_state = false; //->0 Motor off -> 1 Motor   ON
13double cont = 0;
14
15//frequency of PWM: 5kHz
16int timer = 0;
17
18//Other   variables
19int percent = 0;
20int pot_value = 0;
21
22//start variables
23bool   start = false;
24
25
26
27void setup() {
28  pinMode(MOTOR, OUTPUT);
29  digitalWrite(MOTOR,   LOW);
30  pinMode(LED_ON, OUTPUT);
31  pinMode(LED_OFF, OUTPUT);
32  pinMode(3,   INPUT);
33
34  //**SET TIMER0**
35  TCCR0A=(1<<WGM01);        //Set the CTC mode
36   OCR0A = 0x04;             //Value for ORC0A for 2us
37
38  TIMSK0 |= (1 << OCIE0A);   //Set the interrupt request
39  TCCR0B |= (1 << CS01) | (0 << CS00);    //Set   the prescale 1/8 clock
40  //Now timer is on
41
42  //**SET TIMER0**
43
44   digitalWrite(LED_OFF, HIGH);
45  digitalWrite(LED_ON, LOW);
46}
47
48void   loop() {
49
50  pot_value = analogRead(A0);
51
52  //The value doesn't start   from 0 to 100, but from 30 to 100 because with a duty cycle < 30% the motor can't   turn
53  percent = map(pot_value, 0, 1024, 30, 100);
54
55  //**This routine   controls if the state of the push button is changes
56  button_state = digitalRead(3);
57
58   if (button_state == LOW && last_button_state == HIGH) {
59    motor_state = !motor_state;
60   }
61  last_button_state = button_state;
62  //**
63
64
65  if (motor_state   == true ) {
66    //**PWM**
67    if (start == false)
68    {
69      //I must   starting the engine once
70      digitalWrite(LED_ON, HIGH);
71      digitalWrite(LED_OFF,   LOW);
72      digitalWrite(13, HIGH);
73      //cont is in the ISR() routine so   it is like timer variable
74      if (cont > 40000) {
75        start = true;
76         cont = 0;
77      }
78
79    }
80    else {
81       //THIS CREATES   A VARAIBLE PWM
82      if (timer <= (percent * 2))
83        digitalWrite(13,   HIGH);
84      else
85        digitalWrite(13, LOW);
86    }
87    //**PWM**
88   }
89
90  //if motor_state==false motor is OFF so 13 must be LOW
91  else {
92     digitalWrite(13, LOW);
93    digitalWrite(LED_ON, LOW);
94    digitalWrite(LED_OFF,   HIGH);
95    start = false;
96  }
97}
98
99
100//This routine control the pwm   but the sum of high time and low time must be ALWAYS 200us -> 5kHz
101ISR(TIMER0_COMPA_vect)   {   //This is the interrupt request
102
103  timer++;
104  if (start == false &&   motor_state == true)cont++;
105
106  //After 200us ( timer == 200) -> timer = 0
107   if (timer >= 200) timer = 0;
108
109}
110
111
112

//Control motor with PWM

#define MOTOR 13
#define LED_ON 5
#define   LED_OFF 4

//Button variables
int button_state = 0;
int last_button_state   = 1;

//State of motor
bool motor_state = false; //->0 Motor off -> 1 Motor   ON
double cont = 0;

//frequency of PWM: 5kHz
int timer = 0;

//Other   variables
int percent = 0;
int pot_value = 0;

//start variables
bool   start = false;



void setup() {
  pinMode(MOTOR, OUTPUT);
  digitalWrite(MOTOR,   LOW);
  pinMode(LED_ON, OUTPUT);
  pinMode(LED_OFF, OUTPUT);
  pinMode(3,   INPUT);

  //**SET TIMER0**
  TCCR0A=(1<<WGM01);        //Set the CTC mode
   OCR0A = 0x04;             //Value for ORC0A for 2us

  TIMSK0 |= (1 << OCIE0A);   //Set the interrupt request
  TCCR0B |= (1 << CS01) | (0 << CS00);    //Set   the prescale 1/8 clock
  //Now timer is on

  //**SET TIMER0**

   digitalWrite(LED_OFF, HIGH);
  digitalWrite(LED_ON, LOW);
}

void   loop() {

  pot_value = analogRead(A0);

  //The value doesn't start   from 0 to 100, but from 30 to 100 because with a duty cycle < 30% the motor can't   turn
  percent = map(pot_value, 0, 1024, 30, 100);

  //**This routine   controls if the state of the push button is changes
  button_state = digitalRead(3);

   if (button_state == LOW && last_button_state == HIGH) {
    motor_state = !motor_state;
   }
  last_button_state = button_state;
  //**


  if (motor_state   == true ) {
    //**PWM**
    if (start == false)
    {
      //I must   starting the engine once
      digitalWrite(LED_ON, HIGH);
      digitalWrite(LED_OFF,   LOW);
      digitalWrite(13, HIGH);
      //cont is in the ISR() routine so   it is like timer variable
      if (cont > 40000) {
        start = true;
         cont = 0;
      }

    }
    else {
       //THIS CREATES   A VARAIBLE PWM
      if (timer <= (percent * 2))
        digitalWrite(13,   HIGH);
      else
        digitalWrite(13, LOW);
    }
    //**PWM**
   }

  //if motor_state==false motor is OFF so 13 must be LOW
  else {
     digitalWrite(13, LOW);
    digitalWrite(LED_ON, LOW);
    digitalWrite(LED_OFF,   HIGH);
    start = false;
  }
}


//This routine control the pwm   but the sum of high time and low time must be ALWAYS 200us -> 5kHz
ISR(TIMER0_COMPA_vect)   {   //This is the interrupt request

  timer++;
  if (start == false &&   motor_state == true)cont++;

  //After 200us ( timer == 200) -> timer = 0
   if (timer >= 200) timer = 0;

}

Motor_Control

arduino

1//Control motor with PWM
2
3#define MOTOR 13
4#define LED_ON 5
5#define  LED_OFF 4
6
7//Button variables
8int button_state = 0;
9int last_button_state  = 1;
10
11//State of motor
12bool motor_state = false; //->0 Motor off -> 1 Motor  ON
13double cont = 0;
14
15//frequency of PWM: 5kHz
16int timer = 0;
17
18//Other  variables
19int percent = 0;
20int pot_value = 0;
21
22//start variables
23bool  start = false;
24
25
26
27void setup() {
28  pinMode(MOTOR, OUTPUT);
29  digitalWrite(MOTOR,  LOW);
30  pinMode(LED_ON, OUTPUT);
31  pinMode(LED_OFF, OUTPUT);
32  pinMode(3,  INPUT);
33
34  //**SET TIMER0**
35  TCCR0A=(1<<WGM01);        //Set the CTC mode
36  OCR0A = 0x04;             //Value for ORC0A for 2us
37
38  TIMSK0 |= (1 << OCIE0A);  //Set the interrupt request
39  TCCR0B |= (1 << CS01) | (0 << CS00);    //Set  the prescale 1/8 clock
40  //Now timer is on
41
42  //**SET TIMER0**
43
44  digitalWrite(LED_OFF, HIGH);
45  digitalWrite(LED_ON, LOW);
46}
47
48void  loop() {
49
50  pot_value = analogRead(A0);
51
52  //The value doesn't start  from 0 to 100, but from 30 to 100 because with a duty cycle < 30% the motor can't  turn
53  percent = map(pot_value, 0, 1024, 30, 100);
54
55  //**This routine  controls if the state of the push button is changes
56  button_state = digitalRead(3);
57
58  if (button_state == LOW && last_button_state == HIGH) {
59    motor_state = !motor_state;
60  }
61  last_button_state = button_state;
62  //**
63
64
65  if (motor_state  == true ) {
66    //**PWM**
67    if (start == false)
68    {
69      //I must  starting the engine once
70      digitalWrite(LED_ON, HIGH);
71      digitalWrite(LED_OFF,  LOW);
72      digitalWrite(13, HIGH);
73      //cont is in the ISR() routine so  it is like timer variable
74      if (cont > 40000) {
75        start = true;
76        cont = 0;
77      }
78
79    }
80    else {
81       //THIS CREATES  A VARAIBLE PWM
82      if (timer <= (percent * 2))
83        digitalWrite(13,  HIGH);
84      else
85        digitalWrite(13, LOW);
86    }
87    //**PWM**
88  }
89
90  //if motor_state==false motor is OFF so 13 must be LOW
91  else {
92    digitalWrite(13, LOW);
93    digitalWrite(LED_ON, LOW);
94    digitalWrite(LED_OFF,  HIGH);
95    start = false;
96  }
97}
98
99
100//This routine control the pwm  but the sum of high time and low time must be ALWAYS 200us -> 5kHz
101ISR(TIMER0_COMPA_vect)  {   //This is the interrupt request
102
103  timer++;
104  if (start == false &&  motor_state == true)cont++;
105
106  //After 200us ( timer == 200) -> timer = 0
107  if (timer >= 200) timer = 0;
108
109}
110
111
112

//Control motor with PWM

#define MOTOR 13
#define LED_ON 5
#define  LED_OFF 4

//Button variables
int button_state = 0;
int last_button_state  = 1;

//State of motor
bool motor_state = false; //->0 Motor off -> 1 Motor  ON
double cont = 0;

//frequency of PWM: 5kHz
int timer = 0;

//Other  variables
int percent = 0;
int pot_value = 0;

//start variables
bool  start = false;



void setup() {
  pinMode(MOTOR, OUTPUT);
  digitalWrite(MOTOR,  LOW);
  pinMode(LED_ON, OUTPUT);
  pinMode(LED_OFF, OUTPUT);
  pinMode(3,  INPUT);

  //**SET TIMER0**
  TCCR0A=(1<<WGM01);        //Set the CTC mode
  OCR0A = 0x04;             //Value for ORC0A for 2us

  TIMSK0 |= (1 << OCIE0A);  //Set the interrupt request
  TCCR0B |= (1 << CS01) | (0 << CS00);    //Set  the prescale 1/8 clock
  //Now timer is on

  //**SET TIMER0**

  digitalWrite(LED_OFF, HIGH);
  digitalWrite(LED_ON, LOW);
}

void  loop() {

  pot_value = analogRead(A0);

  //The value doesn't start  from 0 to 100, but from 30 to 100 because with a duty cycle < 30% the motor can't  turn
  percent = map(pot_value, 0, 1024, 30, 100);

  //**This routine  controls if the state of the push button is changes
  button_state = digitalRead(3);

  if (button_state == LOW && last_button_state == HIGH) {
    motor_state = !motor_state;
  }
  last_button_state = button_state;
  //**


  if (motor_state  == true ) {
    //**PWM**
    if (start == false)
    {
      //I must  starting the engine once
      digitalWrite(LED_ON, HIGH);
      digitalWrite(LED_OFF,  LOW);
      digitalWrite(13, HIGH);
      //cont is in the ISR() routine so  it is like timer variable
      if (cont > 40000) {
        start = true;
        cont = 0;
      }

    }
    else {
       //THIS CREATES  A VARAIBLE PWM
      if (timer <= (percent * 2))
        digitalWrite(13,  HIGH);
      else
        digitalWrite(13, LOW);
    }
    //**PWM**
  }

  //if motor_state==false motor is OFF so 13 must be LOW
  else {
    digitalWrite(13, LOW);
    digitalWrite(LED_ON, LOW);
    digitalWrite(LED_OFF,  HIGH);
    start = false;
  }
}


//This routine control the pwm  but the sum of high time and low time must be ALWAYS 200us -> 5kHz
ISR(TIMER0_COMPA_vect)  {   //This is the interrupt request

  timer++;
  if (start == false &&  motor_state == true)cont++;

  //After 200us ( timer == 200) -> timer = 0
  if (timer >= 200) timer = 0;

}

Downloadable files

layout_motor_speed_control_tY0ycJvpYw.fzz

Schematic

layout_motor_speed_control_tY0ycJvpYw.fzz

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