Project tutorial


This project will show you how to make a wireless upload Arduino code from your Computer via Bluetooth.

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Components and supplies

61pby065esl  sx679  tnr8syww5d
HC-05 Bluetooth Module
Mfr 25fbf52 2k21 sml
Resistor 2.21k ohm
Mfr 25frf52 10k sml
Resistor 10k ohm
resistor 15K
100nf capacitor
Ph a000066 iso (1) ztbmubhmho
Arduino UNO
prototyping shield

Necessary tools and machines

09507 01
Soldering iron (generic)

Apps and online services

About this project

Step #1: Breadboard the Bluetooth module setup circuit

  • The Bluetooth module used in this project is the HC-05. It is inexpensive and one of the most common modules you'll see in a lot of other projects. The HC-05 is sold bare or mounted to a breakout board. You want one on a 6-pin breakout board. You can find them for sale on eBay and Amazon. The datasheet for the module is here.
  • Using a breadboard, temporarily wire the HC-05 Bluetooth module per the schematic.
  • With 3.3v on the Key pin, the module will enter 38400 baud command mode and will accept AT commands. The Key pin must be connected to 3.3v when the module is powered on. If it is connected afterwards, the module will enter command mode at the default baud rate (as set by the 'AT+UART=' command or 9600 baud from the factory).

Step #2: Upload the setup sketch

  • Get the sketch from here and upload it to your Arduino.

Step #3: Run the setup sketch and enter serial commands

  • Open the serial console and make sure the baud rate is set to 9600 and line endings is set to be "Both NL & CR"
  • Enter the following AT commands into the serial console one by one:
  • AT+ROLE=0
  • AT+POLAR=1,0
  • AT+UART=115200,0,0
  • In order, these commands tell the module to reset to factory settings, switch to slave role (transparent serial bridge), set pin 32 low on Bluetooth connection, change baud rate to match the Arduino Uno programming rate, and to initialize.
  • Disconnect 3.3v from the Key pin and cycle the power to the module. It will now be running at 115200 baud and be in pairing mode.

Step #4: Setup the Bluetooth module in Windows

  • From the Control Panel select Add a Device.
  • Add the Bluetooth module.
  • Select enter pairing code option.

Step #5: Setup the Bluetooth module in Windows

  • 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.

Step #6: Solder a jumper onto the Bluetooth module

  • DIY Arduino Bluetooth Programming Shield•Disassemble the breadboarded circuit. Solder a jumper wire directly to the HC-05's Pin 32.
  • Don't forget to use flux.
  • You may want to use hot glue or tape to protect the joint.

Step #7: Build the programmer circuit

  • Build the programmer circuit onto the prototyping shield.
  • Solder on a female header for the Bluetooth module if you want to be able to easily remove it later.

Step #8: Program the Arduino With Bluetooth!

Power on the Arduino from a battery or AC adapter.

  • In the Arduino IDE, choose the serial port of the Bluetooth module (the lower valued one of the two(21 and 25) and then upload a sketch like normal.


No preview (download only).


This is the circuit after changing the command on the bluetooth module with the arduino
Build the programmer circuit onto the prototyping shield.
Solder on a female header for the Bluetooth module if you want to be able to easily remove it later.
Bt shield circuit3
Pin 32
connect the pin 32 like the circuit diagramme with the arduino
Bt shield circuit3


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