Keychain project

Dining Buddy v6.3

ESP32-C3 OLED Keychain for UCLA Dining Menus + Weather Display

🆕 Newest Features 6.0 -> 6.3

• Safe Wi-Fi Shutdown: Device now safely enters deep sleep when unable to connect to Wi-Fi.
• Manual Wi-Fi Retry: Long press the button to retry Wi-Fi connection without rebooting.
• Smarter Menu Downloads: Optimized algorithm avoids redundant downloads, saving time and bandwidth.
• Bug Fixes & Stability: Various minor improvements for a more reliable experience.
• Custom Enclosure: 3D-printed and designed a protective case for portability.
• PCB Revision 2: Updated layout for smoother button presses and improved assembly.

Overview

Dining Buddy is an ultra-compact ESP32-C3-based keychain device that displays UCLA dining hall menus and real-time weather, with full offline functionality, minimal power use, and intuitive controls—all on a tiny OLED screen.

Menus are downloaded once daily and displayed with smooth auto-scrolling. The device also includes a date selection mode, hall switching, and a live weather page. It deep sleeps after 30 seconds of inactivity and wakes automatically every night at 2:30 AM to rotate cached menu files and download new ones.

All interaction is handled with a single button, and menu data is stored in SPIFFS. The PCB was custom-designed in KiCad for a minimal, keychain-friendly form factor.

Photos

Prototype

Finished Keychain

Finished Solder Assembly

Schematic

PCB

Features

• 📅 View current and future dining menus (up to 6 days)
• 🏛️ Supports Bruin Plate, Epicuria, De Neve, and Rendezvous
• 🌦️ Weather fetch from wttr.in
• 🕒 Deep sleep with scheduled nightly wake (2:30 AM)
• 📡 Wi-Fi download over UCLA Wi-Fi or eduroam
• 🪛 Single-button interaction (short, long, double press)
• 🔋 OLED shuts off in deep sleep to preserve battery
• 🧾 All menus saved as clean, compact .menu files

🔧 Bill of Materials

🕹 User Guide

Navigation is controlled by one button:

Modes:

• Normal Mode: Default menu viewing mode with auto-scroll
• Date Select Mode: Choose a day (up to 5 days ahead)
• Weather Mode: Shows date, time, and latest weather

How Menus Are Managed

• On first boot, menus for the next 5 days are downloaded.
• Every night at 2:30 AM, yesterday’s menus are deleted, future menus are shifted forward, and the new sixth day is fetched.
• Menu data is extracted from HTML pages and saved as readable text.

Setup Instructions

1. Flash the ESP32-C3 with the DiningBuddy sketch using Arduino IDE.
2. Add your local Wi-Fi or eduroam credentials to LOCAL_SSID, LOCAL_PASS, and EAP_* fields.
3. On boot, the device downloads menus and displays the current one.
4. Power off is automatic after inactivity; just press the button to wake.

Hardware

• MCU: ESP32-C3 (Wi-Fi, deep sleep capable)
• Display: 128×32 OLED (SSD1306 via I2C)
• Button: Wired to GPIO 2 (input with pull-up)
• LED: Optional, wired to GPIO 21 via 220Ω resistor
• Power: LiPo or USB 5V
• PCB: Designed in KiCad for ultra-compact fit on a keychain

Future Improvements

• Battery charging circuit on PCB
• Auto time zone detection via Wi-Fi
• Menu item filtering (vegetarian, vegan, etc.)
• BLE companion app?

👤 Author

Jack Shi
📧 jackmshi@ucla.edu
🔬 UCLA Electrical Engineering