Project Report: OCU – Odox Cell Phone Unit

1. Introduction

The OCU (Odox Cell Phone Unit) is a GSM-based communication unit designed using an Arduino microcontroller, a Nextion Display, and a GSM Module. This project demonstrates the integration of these components to create a functional interface capable of making and receiving calls through a user-friendly graphical interface on the Nextion Display.

2. Objective

To design and implement a compact and efficient mobile communication unit using Arduino, GSM module, and Nextion display, capable of displaying call status and performing basic telecommunication functions.

3. Components Required

1. Arduino board
2. GSM Module (SIM900A or compatible)
3. Nextion Display
4. 12V Power Supply for GSM module
5. Connecting wires and jumper cables
6. SIM card
7. Memory card (for TFT file upload)

4. Circuit Connections

Wiring Connections

ComponentConnectionArduino Pin / Port

Nextion +5V→Arduino VDD_5V

Nextion RX→Arduino Pin 11

Nextion TX→Arduino Pin 10

Nextion GND→Arduino GND

GSM RX→Arduino Pin 1 (TX)

GSM TX→Arduino Pin 0 (RX)

GSM GND→Arduino GND

⚡ Power Supply:

Connect the GSM module to a 12V power supply. The Arduino board can be powered through the GSM module.

💡 SIM Installation: Insert a SIM card into the GSM module before powering on the circuit.

5. Software Setup

Step 1: Arduino Program

1. Copy the provided Arduino sketch into a new project in the Arduino IDE.
2. Compile and upload the program to the Arduino board.
3. Ensure the correct COM port and board type are selected before uploading.

Step 2: Nextion Display GUI

1. Open the provided HMI file using Nextion Editor.
2. Design or modify the GUI as desired.
3. Export the GUI as a TFT file.

6. Uploading the TFT File to Nextion Display

Option 1: Using SD Card

1. Format a memory card in FAT32 format.
2. Copy the exported TFT file onto the memory card.
3. Insert the memory card into the Nextion Display’s microSD slot.
4. Power on the display – it will automatically upload the TFT file.
5. After completion, power off the display and remove the SD card.
6. Power on again – the new GUI will appear on the screen.

7. Hardware Assembly Steps

1. Assemble the circuit according to the wiring diagram provided.
2. Insert a SIM card into the GSM module.
3. Connect the 12V power supply to the GSM module.
4. Power on the system – the OCU is now ready for use.

8. Operation

• Upon powering up, the Nextion Display will show the custom GUI.
• The GSM module will initialize and register on the network.
• You can now make or receive calls using the OCU interface.

9. Conclusion

The OCU – Odox Cell Phone Unit successfully integrates Arduino, GSM, and Nextion display technologies to create a working mobile communication interface. This project demonstrates practical implementation of serial communication, embedded interfacing, and graphical UI development for GSM-based applications.

Source code:

here you can find the full source code with documentation, schematics, ino file, HMI file and tft file:

https://github.com/gsmanees/OCU_Odox_Cellphone_Unit

Enjoy !