Wireless Plotter (Mini CNC Plotter + Bluetooth)

Adding a Bluetooth module HC-05 to a CNC Shield V4 allows for wireless control of your CNC machine via software like GRBL Controller or Universal Gcode Sender. Below are the steps to connect and configure the HC-05 module with the CNC Shield V4.I am adding the Bluetooth module HC-05 to my Mini CNC Plotter V2.

1. Arduino Uno
2. Arduino Nano
3. CNC Shield V4
4. Bluetooth module HC-05
5. Three Resistors 1kΩ
6. Jumper Wires
7. Batteries (7V-9V DC power supply)
8. Paper Clip
9. Soldering Iron
10. Data Cable
11. CNC Plotter

Enter AT Command Mode

Before using the HC-05 with the CNC shield, you may need to configure it using AT commands.

Connect the Bluetooth module HC-05 to Arduino Uno as per the circuit Schematics using jumper wires. You will see the LED of Bluetooth module blinking fast.

To enter in AT Command Mode, disconnect the VCC pin of Bluetooth module from Arduino 5V pin.

Take a paper clip and hold the reset button on the Bluetooth module with this clip.

The LED will start blinking slowly, indicating AT mode.

Upload the Bluetooth code on the Arduino Uno board.

After uploading the code, Open Serial Monitor.

Set Baud rate to 9600, Both NL & CR

The following message Appear on the Serial Monitor:

Enter AT Commands

Send following AT Commands one by one to the Bluetooth module from serial monitor. After sending each Message you will see OK message appears on the serial monitor.

AT

AT+ORGL

AT+NAME=MyCNC (Set a name for easy recognition)

AT+ROLE=0 (Set the HC-05 to slave mode for receiving commands)

AT+UART=115200,0,0 (GRBL usually communicates at 115200 baud)

AT+PSWD=1234 (Set a PIN for pairing (optional))

Remove the HC-05 from the Arduino Uno and remove the paper clip.

Connect it to the CNC Shield V4 as per the wiring diagram.

Power on the CNC shield with external power supply (9V DC) and pair the Bluetooth module with your PC

On the PC, connect to the HC-05 via Bluetooth Settings.

Connect it by using Add Bluetooth or other device option.

MyCNC device shown in available Bluetooth devices.

Pair the Bluetooth device using default password "1234"

After completing these steps you will see the bluetooth module is paired with PC

Click on More Bluetooth options (on the right side) to see the Serial COM port for bluetooth module.

Use this Circuit Schematics to use Bluetooth Module with CNC Shield V4

Tx of HC-05 goes to Rx of CNC Shield, and Rx of HC-05 goes to Tx of CNC Shield.

The HC-05 module operates at 3.3V logic, while the CNC shield uses 5V. It’s recommended to use a voltage divider (1kΩ and 2kΩ resistors) on the Rx pin of HC-05 to avoid damage.

If you do not have 2kΩ resistors use two 1kΩ resistors in series (see the second Circuit Schematics diagram)

The CNC Shield V4 typically has a dedicated UART (Tx/Rx) port for connecting external serial devices like Bluetooth modules.

Connect the CNC Shield V4 to any CNC Plotter, I am connecting it to My Mini plotter V2

https://www.instructables.com/Mini-Plotter-V2/

Use a software like GRBL Controller (Universal G-code Sender).

Open UGS

Select the COM port assigned to HC-05 and set baud rate to 115200.

You should now be able to send G-code wirelessly to the CNC machine.

Open Gcode file and send it to the Plotter.

If you have any query regarding this tutorial, feel free to ask in comments section.

Hope you enjoyed this session of Instructables. Thanks for reading my work. I feel glad if you make your own Wireless Plotter with the help of this tutorial.

Stay tuned to my Instructables channel for more upcoming exciting projects.

Thanks again.