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Bluetooth Android Controlled MBED

Table of Contents

  1. Remote control MBED applications using Bluetooth as wireless protocol
  2. Required Components
  3. Connecting HC05 with MBED
  4. Hardware
  5. Building Android App

Remote control MBED applications using Bluetooth as wireless protocol

There have been several blogs on how to communicate with MBED using a Bluetooth module (HC-05 ) module. I will try to show to build the complete chain of control from Android to MBED.

Required Components

Connecting HC05 with MBED

: 1 - Tx P10 - Rx 2 - Rx P9 - Tx 12 - 3.3V Vout - 3.3V 13 - GND GND 31 - PIO8 32 - PIO9 34 - PIO11 GND or 3.3V

Hardware

/media/uploads/prabhuvd/hardware.jpg

Building Android App

Main Screen

/media/uploads/prabhuvd/application_snapshot.png

Clock explained

/media/uploads/prabhuvd/clock_timer.png

Functionality of clear button

/media/uploads/prabhuvd/clear.png

Functionality of Button 1, 2, 3 and 4

/media/uploads/prabhuvd/button_logic.png

Code running on MBEd

include the mbed library with this snippet

#include "mbed.h"

Serial device(p9, p10);


DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
unsigned char recivedchar;

void send_bytes(uint8_t len ,uint8_t data)
{
    device.putc(len);
    while(len>0) {
        device.putc(data);
        len--;
    }
}

int main()
{
    unsigned char rx;
    device.baud(9600);
    while(1) {

        if(device.readable()) {
            rx =device.getc();
            pc.printf("\n Received %x \nSending : %x",rx,rx);
            switch (rx) {
                case 49:
                    /* Turn on LED#1 on receiving 49 */
                    led1 = !led1;
                    send_bytes(1,rx);
                    break;
                case 50:
                   /* Turn on LED#2 on receiving 50 and send 2 bytes of acknowledgment */
                    send_bytes(2,rx);
                    led2 = !led2;
                    break;
                case 51:
                   /* Turn on LED#3  on receiving 51 and send 3 bytes of acknowledgment */
                    led3 = !led3;
                    send_bytes(3,rx);
                    break;
                case 52:
                     /* Turn on LED#4  on receiving 53 and send 4 bytes of acknowledgment */
                    led4 = !led4;
                    send_bytes(4,rx);
                    break;
            }

        }
    }
}
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