Hardware needs:
1. PCB H-bridge L298 (2pcs)
2. Arduino Pro Mini
3. Brushless motor (take from HDD)

1. H-Bridge L298

2. Arduino Pro Mini

1. Understand brushless motor principle

Image of brushless motor of HDD

Search on web, we know that brushless motor has rotating part (called as Rotor) has no contact with electrical wire -> main feature of this motor is can run with high speed
Motor stator will make magnetic field -> when magnetic direction moving -> it will move rotor

Let's see how magnetic field moving:
Stator of motor has 3 wire, connected together at 1 point, other point of wire will connect to power source.
At "phase 1", power (+) is applied to Green coil, and power (-) is applied to Blue coil -> sum of vector magnetic field of Green coil and Blue coil will make magnetic direction as in above picture (horizontal direction) -> this magnetic field will make rotor rotating and align to magnetic direction, then stop at this direction
To move rotor, magnetic field must moving -> see "phase 2"
In "phase 2", power (+) is applied to Red coil, and power (-) is applied to Blue coil -> sum of vector magnetic field will make magnetic direction as in above picture -> this magnetic field will move rotor to this direction
Continue with phase 3, 4, 5, 6 -> magnetic field rotates 1 circle -> rotor also rotates 1 circle

2. Driver for brushless motor

A Driver for brushless motor is used to arrange power (+) and power (-) synchronizing to each coil Blue, Red, Green for rotating magnetic field
Following table is summarize of power (+) and power (-) need to apply each coil at each phase:

Phase	1	2	3	4	5	6
Blue	-	-	N	+	+	N
Red	N	+	+	N	-	-
Green	+	N	-	-	N	+

Three pairs of transistor will be ON/OFF as pattern in above picture to make rotating magnetic field

3. Connection to L298 H-bridge

Half of H-bridge is used to connect to each coil of brushless motor

4. Circuit connection

Schematic diagram by Fritzing:



ENA IN1 is connected to H-bridge 1
ENB IN3 is connected to H-bridge 2
ENC IN1 is connected to H-bridge 3
This project need 3 half of H-bridge  -> need 2 L298 PCB. Here is my result connection:

Result of connection

For this connection, we have pattern code as here:

Phase	1	2	3	4	5	6
Blue	-	-	N	+	+	N
Red	N	+	+	N	-	-
Green	+	N	-	-	N	+
ENA	1	1	0	1	1	0
IN1	0	0	0	1	1	0
ENB	0	1	1	0	1	1
IN3	0	1	1	0	0	0
ENC	1	0	1	1	0	1
IN1	1	0	0	0	0	1

Next is coding for above table

5. Coding for Arduino

/*
 Motor - brushless motor control
 Created 07 Jan. 2018
 This example code is in the public domain.
 http://engineer2you.blogspot.com
 */

const byte en_A = 2;
const byte in_A = 3;
const byte en_B = 4;
const byte in_B = 5;
const byte en_C = 7;
const byte in_C = 8;

int speed_motor = 20;

void setup() {
  pinMode(en_A,OUTPUT);
  pinMode(in_A,OUTPUT);
  pinMode(en_B,OUTPUT);
  pinMode(in_B,OUTPUT);
  pinMode(en_C,OUTPUT);
  pinMode(in_C,OUTPUT);

  // start serial port at 9600 bps:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }
}

void loop() {
  //increasing speed gradually by loop
  for (int i = 0; i<=(21-speed_motor)*5; i++) {
    motor_run();
  }
  
  if (speed_motor > 2) speed_motor = speed_motor - 1; //increasing speed
  Serial.println(speed_motor);  //print out speed to serial port
}

void motor_run() {
  digitalWrite(en_A,1);
  digitalWrite(in_A,0);
  digitalWrite(en_B,0);
  digitalWrite(in_B,0);
  digitalWrite(en_C,1);
  digitalWrite(in_C,1);
  delay(speed_motor); //Phase 1
  digitalWrite(en_A,1);
  digitalWrite(in_A,0);
  digitalWrite(en_B,1);
  digitalWrite(in_B,1);
  digitalWrite(en_C,0);
  digitalWrite(in_C,0);
  delay(speed_motor); //Phase 2
  digitalWrite(en_A,0);
  digitalWrite(in_A,0);
  digitalWrite(en_B,1);
  digitalWrite(in_B,1);
  digitalWrite(en_C,1);
  digitalWrite(in_C,0);
  delay(speed_motor); //Phase 3
  digitalWrite(en_A,1);
  digitalWrite(in_A,1);
  digitalWrite(en_B,0);
  digitalWrite(in_B,0);
  digitalWrite(en_C,1);
  digitalWrite(in_C,0);
  delay(speed_motor); //Phase 4
  digitalWrite(en_A,1);
  digitalWrite(in_A,1);
  digitalWrite(en_B,1);
  digitalWrite(in_B,0);
  digitalWrite(en_C,0);
  digitalWrite(in_C,0);
  delay(speed_motor); //Phase 5
  digitalWrite(en_A,0);
  digitalWrite(in_A,0);
  digitalWrite(en_B,1);
  digitalWrite(in_B,0);
  digitalWrite(en_C,1);
  digitalWrite(in_C,1);
  delay(speed_motor); //Phase 6
}

You might also like: