TI-84 Plus CE Messaging System

A peer-to-peer messaging system for TI-84 Plus CE calculators, built with the CE C Toolchain and ESP32-S3 boards communicating over ESP-NOW.

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How It Works

Each calculator connects via USB to an ESP32-S3. When a message is sent from the calculator, the ESP32-S3 broadcasts it over ESP-NOW — a lightweight Wi-Fi protocol by Espressif — to all other ESP32-S3 boards registered by MAC address. Those boards forward the message to their connected calculators over USB.

[TI-84 CE] <--USB--> [ESP32-S3] <--ESP-NOW--> [ESP32-S3] <--USB--> [TI-84 CE]

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Requirements

Hardware

• One TI-84 Plus CE per user
• One ESP32-S3 board per user (tested on ESP32-S3-DevKitM-1)
• USB-Mini cable for each calculator-to-ESP32 connection
• USB-C cable for ESP32-to-power-supply

Software

• CE C/C++ Toolchain
• PlatformIO
• Visual Studio Code
• A jailbreak program if your calculator's OS version is 5.5.1 or higher (Cesium Shell and arTIfiCE Shell)

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Project Structure

TI-84-Plus-CE-Messaging-System/
├── calc/        # CE C Toolchain source for the calculator client
├── esp32/       # PlatformIO source for the ESP32-S3 firmware
└── pictures/    # Picture references for how to set up. Primarily used as a picture hosting folder for the main .md files

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Getting Started

1. Flash the ESP32-S3

Open esp32/ in PlatformIO. Before building, edit the MAC address table in main.c to include the MAC addresses of every ESP32-S3 in your group:

uint8_t peerMACAdresses[][6] = {
    {0xXX, 0xXX, 0xXX, 0xXX, 0xXX, 0xXX},
};

You can find an ESP32's MAC address by flashing it and reading the boot log output over serial. Build and flash to each board.

2. Build the Calculator Program

Follow the CE C Toolchain setup guide to install the toolchain, then build the calculator source from the calculator/ directory. Transfer the resulting .8xp file in the bin folder to your TI-84 Plus CE using TI Connect CE or TILP.

OS 5.5.1 or higher? You will need to install a jailbreak before running unsigned programs. See JAILBREAK.md for instructions.

3. Connect and Chat

Plug each calculator into its paired ESP32-S3 via USB-C. Launch the messaging program on the calculator. Messages will be sent to all other calculators in the group in real time.

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Versioning

Component	Version
ESP32-S3 Firmware	0.5
Calculator Client	0.2

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Contributing

Contributions are welcome. Please open an issue before submitting a pull request.

1. Fork the repository
2. Create a feature branch (git checkout -b feature/your-feature)
3. Commit your changes (git commit -m 'Add your feature')
4. Push to the branch (git push origin feature/your-feature)
5. Open a pull request

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License

This project is open source and under the MIT License.