Bluetooth HC-06. Arduino. Send. Receive. Send text file. Multitouch. Image

Juan_Antonio · May 22, 2020, 11:42pm

8.- App receives data from Arduino. Clock.Interval. Arduino delay. Buffer.

a)
Clock.Interval = 300
Arduino delay = 200

App cannot process the information because the Clock "is slower" than the Arduino.
The buffer is being filled, values that arrive and have not yet been processed.
When the Buffer reaches a certain value, for example 120, you remove power to the Arduino. What happens with buffer?

b) Change Clock.Interval
Clock.Interval = 100
Arduino delay = 200

Now the Clock "is faster" than the Arduino.
Buffer = 0

Therefore, Clock.Interval < delay Arduino

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int aleatorio;

void setup() { 
  Serial.begin(9600);
}

void loop() { 
    aleatorio = random(0,100);
    Serial.println(aleatorio);
    delay(200); // Clock.Interval < delay Arduino
}

Juan_Antonio · May 23, 2020, 8:07am

9.- A potentiometer in Arduino sends values to the App. Dynamic graph. Shift left.

Here similar example.

p9A0i_bluetooth_dinamico.aia (8.1 KB)

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int value_pot0;

void setup() { 
  Serial.begin(9600);
}

void loop() { 
    value_pot0 = analogRead(A0);
    Serial.println(value_pot0);
    delay(100); // It should be slower than the Clock Interval.
}

Juan_Antonio · May 23, 2020, 9:12am

10.- Three LEDS on-off according to a sequence saved in a file.

p9A0i_bluetooth_secuencia3LED.aia (5.0 KB)

In file rutina2.csv this content:
Levels of: LED11 - LED12 - LED13 - Time in seconds of this combination.
App sends 1-1-0-2*
Arduino set LEDs on, on, off
and wait 2 seconds.
then Arduino sends to App “send_me_next”
When App receives “send_me_next”
App “send_next” combination: 1-0-0-2*

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

char caracter;
String palabra;
int LED11 = 11;
int LED12 = 12;
int LED13 = 13;
int valor11;
int valor12;
int valor13;

int Tiempo = 1000000;
unsigned long currentMillis;
unsigned long previousMillis = currentMillis; 
  
int k1;
int k2;
int k3;
int k4;

void setup() { 
  Serial.begin(9600);
  pinMode(LED11, OUTPUT); 
  pinMode(LED12, OUTPUT); 
  pinMode(LED13, OUTPUT); 
}

void loop() { 
  if(Serial.available()) {
  caracter = Serial.read();
  palabra = palabra + caracter;
        Serial.println(palabra);

  if(caracter == '*') {
      palabra = palabra.substring(0, palabra.length() - 1); // Delete last char *     
      k1 = palabra.indexOf('-');
      valor11 = palabra.substring(0, k1).toInt();
      k2 = palabra.indexOf('-', k1+1);
      valor12 = palabra.substring(k1+1, k2).toInt();
      k3 = palabra.indexOf('-', k2+1);
      valor13 = palabra.substring(k2+1, k3).toInt();
      k4 = palabra.indexOf('-', k3+1);
      Tiempo = 1000 * palabra.substring(k3+1, k4).toInt();
      palabra = "";
      digitalWrite(LED11, valor11);
      digitalWrite(LED12, valor12);
      digitalWrite(LED13, valor13); 
  }

    previousMillis = currentMillis;
} // =>Fin del available
      tiempo();
} // =>Fin del loop

void tiempo() {
  currentMillis = millis();
  if (currentMillis >= (previousMillis + Tiempo)) {
    previousMillis = currentMillis;
    Serial.println("send_me_next"); // Envíame el siguiente.
  }
  }

Juan_Antonio · May 23, 2020, 12:18pm

11.- Virtual Screen with two VerticalArrangement.

p9A0i_bluetooth_virtual.aia (4.1 KB)

bt_29

In this example I have used Send1ByteNumber, I have arbitrarily chosen the numbers 153,168,221.
Arduino returns a byte 48 or 49.

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#define LED13 13
byte StatusLED13;

void setup()
{
  Serial.begin(9600);
  pinMode(LED13, OUTPUT);
}

void loop() { 
  if(Serial.available())
  {
    int dato = Serial.read();
    if(dato == 153){digitalWrite(LED13, HIGH);}
    if(dato == 168){digitalWrite(LED13, LOW);}
    if(dato == 221){
      StatusLED13 = digitalRead(LED13);
      Serial.print(StatusLED13); // Sends 48 or 49
      }
   }
}

Juan_Antonio · May 23, 2020, 5:02pm

12.- App moves two Servos by Sliders.

p9A0i_bluetooth_servos.aia (3.2 KB)

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#include <Servo.h>
Servo servo3;
Servo servo5;
const int pwmPin3 = 3; // Servo3 pin3 PWM
const int pwmPin5 = 5; // Servo5 pin5 PWM

char caracter;
String palabra;
String angulo_1;
String angulo_2;

int k1;

void setup() {
Serial.begin(9600);
pinMode (pwmPin3, OUTPUT); 
pinMode (pwmPin5, OUTPUT);
servo3.attach(pwmPin3);
servo5.attach(pwmPin5);
}

void loop() {

  if(Serial.available())
  {
    caracter = Serial.read();  
    palabra = palabra + caracter; 

if (caracter == '*') {
      Serial.println(palabra);
      palabra = palabra.substring(0, palabra.length() - 1); // Delete last char *
      k1 = palabra.indexOf(',');
      angulo_1 = palabra.substring(0, k1);
      angulo_2 = palabra.substring(k1+1, -1);

      servo3.write(angulo_1.toInt());
      servo5.write(angulo_2.toInt());
      palabra = "";   
  }
      }
} // => Fin Loop

Note: if you use more than 2 servos you will need to power them with an external power source. Video: Each servo needs about 400 mA.

Juan_Antonio · May 23, 2020, 6:15pm

13.- App moves a Stepper motor.

p9A0i_bluetooth_pasopaso.aia (3.1 KB)

In a servo you order:
set 34º
set 12º
set 96º, it is not necessary to know the previous position.
In a stepper motor, you order:
set 20 step clockwise
set 80 step anticlockwise, it is necessary to know the previous position to place it in a new position.
I will use: Stepper motor 28BYJ-48 ULN2003
It is convenient to power this motor through an external source, in this experimental example I will feed it with the 5 V of Arduino.

This code needs Stepper library.

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#include <Stepper.h>
#define STEPS 64

// Secuencia 1-3-2-4
Stepper motor(STEPS, 8, 10, 9, 11); 

char caracter;
void setup() { 
Serial.begin(9600);
motor.setSpeed(200);
}

void loop() { 
if( Serial.available() ) {
  caracter = Serial.read();
  Serial.print(caracter);
  if(caracter == '1'){motor.step(60);}
  if(caracter == '2'){motor.step(-60);}
  if(caracter == '3'){motor.step(510);}
  if(caracter == '4'){motor.step(-510);}
  if(caracter == '5'){motor.step(1020);}
  if(caracter == '6'){motor.step(-1020);}
  if(caracter == '7'){motor.step(2040);}
  if(caracter == '8'){motor.step(-2040);}
  
  if(caracter == 'A'){motor.step(100);}
  if(caracter == 'B'){motor.step(-100);}
  }
}

Juan_Antonio · May 24, 2020, 10:33am

14. Where do we connect the Bluetooth module in Arduino UNO?

p9A0i_bluetooth_Serial.aia (2.9 KB)

Terminals 0 (RX) and 1 (TX) are used by Arduino as the default Serial RX/TX. Use it to upload sketch, Serial Monitor, Bluetooth. So when we are going to upload a sketch for Bluetooth we must disconnect the RX cable from the Arduino.
We can use other terminals to connect the Bluetooth module, for example 10 and 11, in this case we need the “SoftwareSerial” library. Now when we upload a sketch it is not necessary to remove the RX cable.

- CODE FOR MODULE IN default RX/TX pin 0 and 1 of Arduino.

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#define Pin13  13
char caracter;

void setup() { 
  Serial.begin(9600);
  pinMode(Pin13, OUTPUT); 
}

void loop() { 
  if(Serial.available()) {
    caracter = Serial.read();
    if(caracter == 'a'){ digitalWrite(Pin13, HIGH);}
    if(caracter == 'b'){ digitalWrite(Pin13, LOW);}
    Serial.println(caracter);
  } 
}

- CODE FOR MODULE IN pin10 and pin11 with SoftwareSerial library.

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#include <SoftwareSerial.h>
SoftwareSerial I2CBT(10,11);
// El TX del módulo BT va al pin10 del Arduino
// El RX del módulo BT va al pin11 del Arduino

#define Pin13  13
char caracter;

void setup() { 
  I2CBT.begin(9600); // To read and write Bluetooth
  Serial.begin(9600); // To print in Serial Monitor
  pinMode(Pin13, OUTPUT); 
}

void loop() { 
  if(I2CBT.available()) {
    caracter = I2CBT.read();
    if(caracter == 'a'){ digitalWrite(Pin13, HIGH);}
    if(caracter == 'b'){ digitalWrite(Pin13, LOW);}
    Serial.println(caracter); // Serial Monitor
    I2CBT.println(caracter);  // return Bluetooth
    //  I2CBT.write(caracter);  // return Bluetooth
  } 
}

Juan_Antonio · May 24, 2020, 11:47am

15.- Send text file from Server to Client and from Client to Server. Message Mobile to Mobile by Bluetooth.

p9A0i_BT_Server_File.aia (3.3 KB)

p9A0i_BT_Client_File.aia (3.4 KB)

- Blocks Server.

- Blocks Client.

Juan_Antonio · May 26, 2020, 5:32pm

16.- Send Image file from Server to Client and from Client to Server.

This example is only experimental, there are problems with file size, clock interval, conversion … Try.

p9A0i_BT_Server_Image.aia (41.9 KB)

p9A0i_BT_Client_Image.aia (55.6 KB)

- Blocks Server.

- Blocks Client.

Juan_Antonio · May 26, 2020, 5:38pm

17.- Write number with KeyPad in Arduino and sends to App by Bluetooth. LCD I2C.

p9A0i_bluetooth_teclado.aia (1.8 MB)

Write number with KeyPad + I2C: 123, 4567, 89, 61 then write # (as ENTER)
That number is displayed on the I2C LCD and is sent via Bluetooth.
Depending on the number sent, the image of a monkey, lion, bear or martians will be displayed in App.

// Juan A. Villalpando
// http://kio4.com/appinventor/9BA_bluetooth_teclado_LCD.htm

#include <Wire.h>
#include <Keypad_I2C.h>
// Pantalla LCD
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
// LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);

String clave = "";
String clave_old = "";

const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {0, 1, 2, 3};
byte colPins[COLS] = {4, 5, 6, 7};

int i2caddress = 0x20; // Module I2C Keyboard.

Keypad_I2C kpd = Keypad_I2C( makeKeymap(keys), rowPins, colPins, ROWS, COLS, i2caddress);

void setup() {
  Serial.begin(9600);
  kpd.begin();
  lcd.begin(16,2);// Columnas y filas de LCD.
 
}

void loop() {
  char key = kpd.getKey();
  clave = clave + (String) key;
  if (key == '#') {
    clave = clave.substring(0, clave.length() - 1); // Delete last char #   
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print(clave);
    lcd.setCursor(0,1);
    lcd.print(clave_old);
    clave_old = clave;
    Serial.println(clave);
    clave = "";
  }
  delay(100);
}

Libraries LcdCristal_I2C and KeyPad_I2C.

Juan_Antonio · May 27, 2020, 3:49pm

18.- Poor man’s circuit.

In the example above, the poor man has no LCD, no I2C module, and no KeyPad.
Remove the wire from terminal 0 of the Arduino.

bt_48

In Design, DelimiterByte = 35 (it is #)

// Juan A. Villalpando
// http://kio4.com/appinventor/9BA_bluetooth_teclado_LCD.htm

char key = 0;
String clave = "";

void setup() {
Serial.begin(9600);
}

void loop() {
if (Serial.available() > 0) {
  key = Serial.read();
  clave = clave + key;
      if (key == '#') {
        Serial.print(clave);
        // Example sends: 123#
        clave = ""; 
      }
  }
}

Now in Serial Monitor write number, 123#

bt_47

Juan_Antonio · May 27, 2020, 5:53pm

19.- Arduino Interrupts sends data to App.

p9A01_bluetooth_interrupt.aia (2.3 KB)

Arduino UNO has two pins for interruptions (pin2 and pin3). ESP32 has 32 interrupt pins).
Arduino interrupts: https://www.arduino.cc/reference/en/language/functions/external-interrupts/attachinterrupt/
When pin2 RISING causes an interrupt and calls function on_13
When pin3 RISING causes an interrupt and calls function off_13

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

#define LED13 13

void setup()
{
  Serial.begin(9600);
  attachInterrupt(digitalPinToInterrupt(2), on_13, RISING);
  attachInterrupt(digitalPinToInterrupt(3), off_13, RISING);
  pinMode(LED13, OUTPUT);
}

void loop()
{
  // 
}

 // Interruptions ISR.
void on_13() // When pin2 RISING...
{
   digitalWrite(LED13, HIGH);
   Serial.print(1);
}

void off_13()  // When pin3 RISING...
{
   digitalWrite(LED13, LOW);
   Serial.print(0);
}

Juan_Antonio · May 30, 2020, 11:38am

20.- Get message when Bluetooth has disconnection failure.

p9A01_bluetooth_faliure.aia (4.0 KB)

Arduino sends random numbers to App:

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int aleatorio;

void setup() { 
  Serial.begin(9600);
}

void loop() { 
    aleatorio = random(0,100);
    Serial.println(aleatorio);
    delay(400); // Clock.Interval < delay Arduino
}

App receives those numbers and shows.
Disconnect the power cable from the Arduino.
You will get the approximate time of that disconnection.

bluetooth_fallo3937×1150 93.9 KB
In the previous blocks observe SendText = 3, this is dumb number, when that number is sent and the Bluetooth does not receive it, we get error 516: Unable to write: Broken pipe.

Juan_Antonio · May 30, 2020, 1:11pm

21.- Arduino sends three random numbers to App.

p9A0i_bluetooth_aleatorios.aia (3.9 KB)

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int x;
int y;
int z;
String datos;

void setup() {
 Serial.begin(9600);
}

void loop() {
x = random(0, 10);
y = random(10, 100);
z = random(100,1000);
datos = (String) x + "," + (String) y + "," + (String) z;
Serial.println("Números aleatorios:");
Serial.println("Random numbers:");
Serial.println(datos);

delay(800);
}

Note that it only shows up when a list of 3 items arrives. Not shown:
Serial.println(“Números aleatorios:”);
Serial.println(“Random numbers:”);

Juan_Antonio · May 31, 2020, 11:14am

22.- JoyStick in Arduino sends values. Move a ball.

p9A0_bluetooth_laberinto.aia (115.7 KB)

JoyStick Arduino.

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int x;
int y;
int c;
String datos;

void setup() {
 Serial.begin(9600);
 pinMode(2,INPUT_PULLUP);
}

void loop() {
  x = analogRead(A0);
  y = analogRead(A1);
  if (digitalRead(2) == HIGH){c=0;} else {c=1;}
  datos = (String) x + "," + (String) y + "," + (String) c;
  Serial.println(datos);
  delay(100);
}

Variables x,y: Ball.MoveTo and DrawLine.
Variable c: Canvas.Clear (when press JoyStick)

Juan_Antonio · June 2, 2020, 2:29pm

23.- Arduino sends random numbers every second and every two seconds.

p9A0i_bluetooth_aleatorio2.aia (3.4 KB)

// Juan A. Villalpando
// http://kio4.com/appinventor/9A0_Resumen_Bluetooth.htm

int alea_1;
int alea_2;
unsigned long tiempo_actual_1 = 0;
unsigned long tiempo_actual_2 = 0;

void setup() { 
  Serial.begin(9600);
}

void loop() {
  if((millis()-tiempo_actual_1)>= 1000){
          int alea_1 = random(0,100);
          tiempo_actual_1 = millis();
          Serial.println(String(alea_1));
  }
  if((millis()-tiempo_actual_2)>= 2000){
          int alea_2 = random(200,300);
          tiempo_actual_2 = millis();
          Serial.println(String(alea_2));
  }
}

Juan_Antonio · November 24, 2020, 6:18am

24.- Press a button continuously and send a character.

In this topic @Povilas_Kasparas, @Taifun and @ABG discuss how to send a character continuously while pressing a button.

char caracter;

 void setup(){  
  Serial.begin(9600);  
 } 
  
 void loop() { 
 if(Serial.available()) {
  caracter = Serial.read();
  Serial.println(caracter);
  }
}

Povilas_Kasparas · November 25, 2020, 7:20pm

Thank you a lot saved me

Juan_Antonio · November 26, 2020, 11:11am

25.- Simulation of an arithmia.

p9BC_Bluetooth_ECGi.aia (12.4 KB)

Arduino sends a random level (90...100), with a random delay (400...1600)
appinventor_ECG

void setup(){
  Serial.begin(9600);
}

void loop(){
      int nivel = random(90,100);
      int ritmo = random(400,1600);
      delay(ritmo);
      String mensaje = (String) nivel + "," + (String) ritmo;
      Serial.println(mensaje);
}

App Receives Text (98,977), gets the level (98) and draws it on a Canvas.

For a more realistic process, use the module AD8232

Here in Spanish:
http://kio4.com/appinventor/9BC_bluetooth_corazon.htm

Juan_Antonio · November 28, 2020, 10:03pm

26.- App sends text. readStringUntil. readString.

p9A1_bluetooth_textoi.aia (2.2 KB)

bluetooth_enviartexto1

1.- readStringUntil

char end_char = '\n';
String texto;

void setup() { 
Serial.begin(9600);
}

void loop() { 
  if(Serial.available()) {
    texto = Serial.readStringUntil(end_char);
    Serial.println(texto);
  }
}

ooooooooooooooOOOOOoooooooooooooo

2.- readString

String texto;

void setup() { 
Serial.begin(9600);
Serial.setTimeout(100);
}

void loop() { 
  if(Serial.available()) {
    texto = Serial.readString();
    Serial.println(texto);
  }
}

26B.- Example with readString. Return.
[Module Bluetooth in pin 2 and 3 of Arduino]

p9A1_bluetooth_textoi_2.aia (3.0 KB)

#include <SoftwareSerial.h>
SoftwareSerial Bluetooth(2,3);
String texto;

void setup() { 
Serial.begin(9600);
Bluetooth.begin(9600);
Bluetooth.setTimeout(100);
}

void loop() { 
  if(Bluetooth.available()) {
    // texto = Bluetooth.readStringUntil('\n');
    texto = Bluetooth.readString();
    Serial.println(texto);
    Bluetooth.println(texto);
  }
}