Wi-Fi Enabled Price Display for Gold & Bitcoin

This project displays real-time prices for Gold and Bitcoin in EUR using an ESP32 microcontroller. The data is fetched from the MetalPriceAPI and shown on an OLED screen. The device fetches prices at user-defined intervals and shows the most recent data. Configuration is done via a web interface, allowing easy entry of Wi-Fi credentials and API key.

Features:

• Real-time Gold & Bitcoin Prices in EUR: Prices are fetched using the MetalPriceAPI.
• OLED Display: Shows Gold and Bitcoin prices alternately every 10 seconds.
• Web Interface for Configuration: The device starts in Access Point mode to allow users to configure Wi-Fi credentials, API key, and fetch cycle time through a web page.
• Local Storage (SPIFFS): Stores credentials and settings on the ESP32, so they are retained even after a reboot.
• User-defined Fetch Cycle: Allows users to set the frequency (in minutes) for fetching price updates via the web interface.
• Automatic Price Updates: Prices are updated automatically according to the fetch cycle time.

Components:

• ESP32 Microcontroller: Manages Wi-Fi connections, API requests, and display.
• OLED Display (128x64): Displays Gold and Bitcoin prices alternately.
• SPIFFS: Local storage on ESP32 to save configuration settings.
• MetalPriceAPI: Provides real-time gold and Bitcoin price data.

Hardware Requirements:

• ESP32 Development Board
• OLED Display (128x64, I2C compatible)
• Connecting Wires

Libraries Used:

The following libraries are required to run the project. Install them using the Arduino Library Manager:

• WiFi by Arduino: Connects the ESP32 to Wi-Fi networks.
• WebServer by ESP32: Handles HTTP requests for the web interface.
• SPIFFS by Arduino: Local storage on ESP32.
• HTTPClient by Arduino: Handles HTTP requests for API calls.
• ArduinoJson by Benoît Blanchon: JSON parsing and serialization.
• Wire by Arduino: I2C communication with the OLED.
• U8g2lib by olikraus: Controls the OLED display.
• Time by Michael Margolis: Provides functions for handling time on the ESP32.

Setup Instructions:

Hardware Setup:

1. Connect the OLED display to the ESP32 using I2C pins:

   • SDA to GPIO 8
   • SCL to GPIO 10

2. Ensure the ESP32 has access to your local Wi-Fi.

Software Setup:

1. Download the Project: https://github.com/maximal-max/C3-Mini/blob/main/0.66_OLED/latest_current_gold_and_bitcoin_prices_in_EUR.ino

2. Open the Project in the Arduino IDE:

   • Launch Arduino IDE and go to File > Open. -Select the project folder you cloned and open the main.ino file.

3. Install Required Libraries:

   • 1. Go to Sketch > Include Library > Manage Libraries.
   • 2. Search for and install:
   • WiFi by Arduino
   • WebServer by ESP32
   • HTTPClient by Arduino
   • ArduinoJson by Benoît Blanchon
   • Wire by Arduino
   • U8g2lib by olikraus
   • SPIFFS by Arduino
   • Time by Michael Margolis

Upload the Code to your ESP32:

1. Select the appropriate ESP32 board in Tools > Board.
2. Choose the correct port under Tools > Port.
3. Click the Upload button to flash the code to your ESP32.

Web Interface Configuration:

Initial Setup:

1. After uploading the code, the ESP32 will enter Access Point mode if no Wi-Fi credentials are stored.
2. Connect to the ESP32's Wi-Fi network named ESP32_Config from your phone or computer.

Configure Wi-Fi and API Key:

1. Open a browser and go to http://192.168.4.1.
2. Enter your Wi-Fi SSID, password, API key, and fetch cycle time (in minutes) via the web interface.
3. Click Save to store your settings on the ESP32.
4. After saving, the ESP32 will attempt to connect to the specified Wi-Fi network.

Reboot and Connect:

1. After the ESP32 reboots, it will attempt to connect to your Wi-Fi network.
2. If successful, it will start fetching and displaying real-time prices.

Fetch Cycle Considerations:

• The MetalPriceAPI's free plan allows up to 100 requests per month.
• For example, to fetch data once per day, set the cycle to 1440 minutes (24 hours).
• Be mindful of the request limits to avoid reaching the API quota.
• If more frequent updates are needed, consider upgrading your API plan.

Usage:

• The ESP32 will show:

  • Gold Price (EUR/gram) every 10 seconds.
  • Bitcoin Price (EUR/BTC) every 10 seconds.
  • Last Update Time is displayed for 10 seconds every minute.

• Price Updates: The device fetches the latest prices based on your set cycle.

• OLED Display: Gold and Bitcoin prices alternate every 10 seconds.

• Offline Data: If the device can't fetch new data, it will show the last known prices saved in SPIFFS.

Troubleshooting:

Wi-Fi Connection Issues:

• Ensure the SSID and password are correct.

API Errors:

• Check the internet connection or verify the API key.

SPIFFS Errors:

• Reformat the file system if needed.

Tips:

• Use the Serial Monitor for debugging and log messages.
• Ensure the OLED display is wired correctly.
• If credentials don't save, check available space on the ESP32 file system.

Future Enhancements:

• Add support for more cryptocurrencies or precious metals.
• Enable manual refresh of prices through the web interface.
• Allow dynamic adjustments to fetch cycle and display mode without rebooting.

License:

This project is open-source and released under the MIT License.

Acknowledgments:

• Thanks to olikraus for the U8g2lib library.
• Thanks to Benoît Blanchon for ArduinoJson.
• Thanks to Michael Margolis for the Time library.
• MetalPriceAPI for providing real-time price data – MetalPriceAPI.