README_sp500_dashboard.txt S&P 500 E-Ink Dashboard (TRMNL Integration)
Overview
This project creates a lightweight, automated pipeline that displays S&P 500 market data on a terminal-style e-ink display (TRMNL).
The system consists of: 1. A Google Sheet that refreshes periodically 2. An HTML dashboard that pulls and formats the data 3. A TRMNL device that renders the HTML
Architecture
Google Sheets → HTML Dashboard → TRMNL Display
Google Sheet
The Google Sheet serves as the data source.
Features: - Uses GOOGLEFINANCE() to retrieve S&P 500 data - Refreshes automatically - Stores key-value pairs in columns A and B
HTML Dashboard
The HTML document pulls data from the Google Sheet using the Google Visualization API.
Data Retrieved
The HTML dashboard retrieves and displays the following S&P 500 values from the worksheet:
- Opening price
- Last (current) price
- Change
- Percent change
These values are parsed from the key-value structure in the worksheet and rendered dynamically.
Hosting
The HTML file must be hosted publicly (e.g., GitHub Pages, Netlify).
TRMNL Integration
TRMNL loads the hosted HTML via a public URL and displays it on an e-ink screen.
Limitations
- Data may be delayed due to GOOGLEFINANCE
- Sheet recalculation timing is variable
- Not true real-time market data
Summary
Google Sheets provides the data, the HTML formats and displays it, and TRMNL renders it on an e-ink display.