Arduino-Programmer-via-HC-05

Step 1

First of all, you need to configure your HC-05 module. Sketch is below.

void setup() {

  Serial.begin(38400);
  delay(500);

  Serial.println("AT+NAME=ArduinoNano-Flasher");
  delay(500);

  /*Use this baudrate if using for Arduino Uno, Bluino and Mega2560*/
  //Serial.println("AT+UART=115200,0,0");

  /*Use this baudrate if using for Arduino Nano, Leonardo, Micro, Pro Mini 3V3/5V and Duemilanove */
  Serial.println("AT+UART=57600,0,0");
  delay(500);

  Serial.println("AT+POLAR=1,0");
  delay(500);

  //Set the password
  Serial.println("AT+PSWD=0000");
  delay(500); 
}

void loop() {

} 

copy/paste it and flash it onto your arduino. Sketch file is also available in the repo.

Step 2

Hardware:

• Capacitor 1uf/16v
• Arduino Nano
• Bluetooth HC-05 module
• Mini breadboard
• Jumper wires
• Resistor 100 ohm

Time to setup our HC-05. At step 1 you have flashed arduino with sketch that will set up bluetooth module.

• Press and hold KEY button on HC-05 module
• Plug USB cable to power on arduino
• Keep holding the button, wait about 5 seconds
• Unplug and re plug USB for reset from AT command mode

If everything went well - after replug you should be able to discover a bluetooth device named "ArduinoNano-Flasher". Also red led will be blinking fast on HC-05 module.

Step 3

Open your bluetooth software pair with flasher and setup a com-port. I'm not giving any details here as the process differs in operating systems. I guess macos and linux users will find solution easily. For windows - just a hint: Once you setup a pairing, two virtual COM-ports will be created automaticaly. One is inbound and antoher one is outbound. You have to use outbound oneto flash.

Once all done, try flashing a blink a example via bluetooth.

Notes

• Resitor is not needed if you got a another bluetooth module with 5V levels.
• HC-05 module: https://aliexpress.ru/item/32786773297.html?spm=a2g0s.9042311.0.0.5d5233edrY1MiP&_ga=2.100804098.208141165.1606898230-1182854936.1582557877&_gac=1.250168948.1603013387.CjwKCAjwz6_8BRBkEiwA3p02VVee70Haqq5UUrKVNEZzYKKx9TKSEBXcL9Dq5UvrGHL8TlBh0VbyCxoCgygQAvD_BwE&sku_id=10000010469459308
• HC-06 wont work. You need exactly HC-05.