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Bluetooth Android Controlled MBED
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 bring all the information on one page from android application development to firmware on MBED. Hope this helps :)
Ingredients of the experiment¶
- 1. Bluetooth HC-05 ( pin description of the same can be referred to https://mbed.org/users/edodm85/notebook/HC-05-bluetooth/
- 2. Android Phone
- 3. Installation of Android development environment using MIT App inventor http://appinventor.mit.edu/explore/get-started.html
Connecting HC05 with MBED¶
| Pin- HC05 | Pin-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¶
Building Android App¶
Main Screen¶
Button Logic¶
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);
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;
}
}
}
}