MeshTalk

MeshTalk is a BLE Mesh–based chat application built for the ESP32 platform using the ESP-IDF framework.
It allows multiple nodes to communicate over a Bluetooth Mesh network using a simple text-based protocol,
with support for hardware input/output (joystick + button for navigation, SSD1306 OLED display for UI).

Provisioning is done using the nRF Mesh mobile application (Nordic Semiconductor).

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✨ Features

• BLE Mesh Chat: Send and receive short text messages across mesh nodes.
• Persistent User Storage: Nodes remember contacts across reboots using NVS.
• Online/Offline Status: Real-time status indicators for network participants.
• Auto Node Discovery: Automatically registers unknown nodes when messages arrive.
• Vendor Model: Custom vendor-specific model for chat message handling.
• Provisioning: Static and dynamic provisioning supported.
  • ✅ Dynamic provisioning using the nRF Mesh app.
• Hardware UI:
  • SSD1306 OLED screen for displaying messages.
  • PS2 joystick with button for user input and navigation.
  • Online/offline status indicators (● ○) next to usernames.
• Message Enhancements:
  • Timestamps using esp_timer_get_time().
  • Compact binary protocol (1-byte type fields).
  • Aggregated messages for efficiency.

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🏗️ Architecture

• Hardware Layer: ESP32, SSD1306 OLED, PS2 Joystick
• BLE Mesh Stack: ESP-IDF Bluetooth Mesh implementation
• Application Layer: Message handling, UI, contact management
• Storage: NVS (Non-Volatile Storage) for persistent contacts
• Protocol: Custom vendor model for chat messages

🖥️ Display Driver

This project uses the nopnop2002/esp-idf-ssd1306 driver
via ESP-IDF's managed_components for SSD1306 OLED support.

🔧 Hardware Setup

• ESP32 development boards (≥2 nodes for chat).
• SSD1306 OLED (I2C pins: SDA, SCL).
• PS2 Joystick module (VRx, VRy, SW pins).
• Breadboard + jumper wires.

Connections:

• OLED:
  • VDD → 3.3V
  • GND → GND
  • SCL → ESP32 GPIO22 (default I2C SCL)
  • SDA → ESP32 GPIO21 (default I2C SDA)
• Joystick:
  • +5V → 3.3V (⚠️ many modules accept 3.3V)
  • GND → GND
  • VRx → ADC pin (e.g., GPIO34)
  • VRy → ADC pin (e.g., GPIO35)
  • SW → GPIO (e.g., GPIO32)

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📲 Provisioning with nRF Mesh App

1. Install the nRF Mesh app from Google Play or App Store.
2. Power up your ESP32 nodes with the MeshTalk firmware flashed.
3. Open the app and scan for unprovisioned devices.
4. Select your ESP32 device and provision it:
   • Add a NetKey and AppKey.
   • Bind the AppKey to the vendor model.
5. After provisioning, you can send messages between nodes.

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▶️ Getting Started

Requirements

• ESP-IDF v5.x
• Python 3.x
• nRF Mesh mobile app (for provisioning)

Build & Flash

# Set up ESP-IDF environment
. $HOME/esp/esp-idf/export.sh

# Build
idf.py build

# Flash to ESP32
idf.py -p /dev/ttyUSB0 flash monitor

## 🚀 Usage
1. **Power on** 2+ ESP32 nodes with MeshTalk firmware.
2. **Provision** each node using the nRF Mesh app.
3. **Navigate** using the joystick to select contacts.
4. **Send messages** by typing and pressing the joystick button.
5. **View status** - online contacts show ●, offline show ○.