An IoT-driven timing solution for the 39th AIU West Zone Youth Festival.
The physical BLE Timer IoT device in action at CVM University.
The 39th AIU Time Control System is a professional-grade speech timer designed to manage competitive university events with precision. It bridges the gap between physical hardware and mobile convenience using ESP32 and Bluetooth Low Energy (BLE).
- 📱 Smart Connectivity — Automatic filtering and connection to
NOT_CNT_XXXXdevices. - ⏲️ Advanced Timing — Managed phases for PREP, MIN, PERF, and GRACE periods.
- 💡 Live Sync — Real-time countdown on both the app and the physical 8x32 LED matrix.
- 🔒 Secure Operations — PIN-based authentication to prevent unauthorized control during sessions.
- 📊 Performance Logs — Automatically logs session data including configurations and total overtime.
The device communicates status through a high-visibility RGB LED and a matrix display:
| Phase | LED Color | Logic |
|---|---|---|
| Preparation | 🟡 Yellow | Counts down the user-defined setup time. |
| Session Start | 🟢 Green | Double green blink to signal the speaker to begin. |
| Min Threshold | 🔵 Blue | Quick blue flash when the minimum time is reached. |
| Overtime (Grace) | ⚫ Off | Display counts UP; no LED distractions for the speaker. |
| Conclusion | 🔴 Red | 5 red flashes to signal the official end of the round. |
- Microcontroller: ESP32 (utilizing BLE 4.2 stack).
- Display: MAX7219 Driven 8x32 LED Matrix (0-15 brightness levels).
- Format: Supports
MM:SSand automatically switches toH:MMfor sessions ≥ 100 minutes.
- Hardware: Flash the firmware to your ESP32 and wire according to the diagram above.
- Permissions: Ensure Bluetooth and Location (on Android) are enabled for scanning.
- Authentication: Set a 4-digit PIN upon first launch to secure the interface.
- Testing: Use the "Test Device" menu in Settings to run the R/G/B and Segment diagnostic.
Developed for the Association of Indian Universities (AIU)
BLE Timer IoT App v1.0.0