Arduino - Upload sketch using Bluetooth - Notes

1. HC-05 and Arduino Connectivity for AT mode

- Connect 5v to 5v
- Connect GND to GND
- Connect Tx to pin 2
- Connect Rx to pin 3 and GND through resistors (2k and 1k) as shown below



- EN and state pins remain hanging
- Remove the 5v connection to HC-05
- Remove the connections to Pin 2 and 3 of arduino
- Connect the arduino to PC to power on using USB
- Upload the sketch below

#include <SoftwareSerial.h>

SoftwareSerial BTserial(2, 3); // RX | TX // Connect the HC-05 TX to Arduino pin 2 RX.

// Connect the HC-05 RX to Arduino pin 3 TX

char c = ' ';

void setup() {

Serial.begin(9600);

Serial.println("Arduino is ready");

Serial.println("Remember to select Both NL & CR in the serial monitor");

// HC-05 default serial speed for AT mode is 38400

BTserial.begin(38400);

}

void loop() {

// Keep reading from HC-05 and send to Arduino Serial Monitor

if (BTserial.available()) {

c = BTserial.read();

Serial.write(c);

}

// Keep reading from Arduino Serial Monitor and send to HC-05

if (Serial.available()) {

c = Serial.read();

BTserial.write(c); }

}


- Keep holding the button on HC-05
- Connect 5v to 5v, the HC-05 will go into AT mode
- Release the button on HC-05
- Reconnect hc-05 to pin 2 and 3
- Execute the following AT commands through serial monitor (make sure the baud rate is set to 9600 and line endings is set to be "Both NL & CR")

• AT+ROLE=0
• AT+POLAR=1,0
• AT+UART=115200,0,0

- Remove the USB connection to arduino

2. Setup hc-05 with PC

- Power arduino with AA cells (4.8 v)
- From the Control Panel select Add a Device.
- Add the Bluetooth module.
- Select enter pairing code option.
- Enter "1234" for the pairing code.
- At the Add a device success window, click Close.
- Device ready to use. The OS will create two serial COM ports associated with the device. Always use the one with the lower number.

3. Solder a jumper onto Bluetooth module on Pin 32

4. Build ONLY the RESET pin connections and change pin 2 and 3 connections to pin 0 and 1 respectively as shown below - keeping rest all the above circuit the same




5. Program arduino with Bluetooth.

6. References

http://www.joshuanewell.com/electronics/arduino-programming-via-bluetooth

https://create.arduino.cc/projecthub/youssef-sabaa/arduino-bluetooth-programming-shield-wireless-upload-code-1a397c

https://www.instructables.com/id/AT-Commands-for-Bluetooth-Module-HC-05-W-EN-Pin-an/

http://www.martyncurrey.com/arduino-with-hc-05-bluetooth-module-in-slave-mode/