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Diffstat (limited to '_projects/etlas.md')
| -rw-r--r-- | _projects/etlas.md | 36 |
1 files changed, 18 insertions, 18 deletions
diff --git a/_projects/etlas.md b/_projects/etlas.md index 3b62ba3..fdfd42a 100644 --- a/_projects/etlas.md +++ b/_projects/etlas.md @@ -7,9 +7,9 @@ layout: post --- Etlas is a news, stock market, and weather tracker powered by an ESP32 NodeMCU -D1, featuring a 7.5-inch {{< link src="https://www.waveshare.com/" -class="external" target="_blank" rel="noopener noreferrer">}}Waveshare{{< -/link>}} e-paper display and a DHT22 sensor module. +D1, featuring a 7.5-inch <a href="https://www.waveshare.com/" class="external" +target="_blank" rel="noopener noreferrer">Waveshare</a> e-paper display and a +DHT22 sensor module. <table style="border: none;"> <tr style="border: none;"> @@ -18,9 +18,9 @@ class="external" target="_blank" rel="noopener noreferrer">}}Waveshare{{< </tr> </table> -The top left panel displays the end-of-day stock prices from the {{< link -src="https://polygon.io/" class="external" target="_blank" -rel="noopener noreferrer" >}}Polygon.io{{</link >}} API, relayed through my own +The top left panel displays the end-of-day stock prices from the <a +href="https://polygon.io/" class="external" target="_blank" +rel="noopener noreferrer">Polygon.io</a> API, relayed through my own FastCGI-wrapped Flask app hosted on a VPS. The stock symbols can be configured through the Flask app's application settings. The server.fcgi script enclosed in the tarball at the end of the page contains the Flask app. @@ -34,29 +34,29 @@ Etlas downloads time series data as CSV and computes the price curves on the ESP32. The more prominent panel on the right of the e-paper display shows local -(Singapore) and world news from the {{< link -src="https://www.channelnewsasia.com/" class="external" target="_blank" -rel="noopener noreferrer" >}}Channel News Asia{{< /link>}} RSS feed. The MCU -downloads and parses XML data from the RSS feed directly before rendering it to -the display. Although I did it this way to avoid writing server code, it limits -the feeds from which Etlas can receive data. In a future version, I will relay -the RSS feed through a server (like the stock prices) to make it more flexible. +(Singapore) and world news from the <a href="https://www.channelnewsasia.com/" +class="external" target="_blank" rel="noopener noreferrer">Channel News Asia</a> +RSS feed. The MCU downloads and parses XML data from the RSS feed directly +before rendering it to the display. Although I did it this way to avoid writing +server code, it limits the feeds from which Etlas can receive data. In a future +version, I will relay the RSS feed through a server (like the stock prices) to +make it more flexible. The bottom panels (middle and right) display the temperature and relative humidity from a DHT22 sensor. The DHT22 driver, arguably the most interesting part of the software, reads real-time sensor data by comparing relative pulse widths. The pulses themselves are too quick for the ESP32 to reliably measure -directly. I ported {{< link src="https://github.com/Fonger/ESP8266-RTOS-DHT" -class="external" target="_blank" rel="noopener noreferrer" >}}this{{< /link>}} +directly. I ported <a href="https://github.com/Fonger/ESP8266-RTOS-DHT" +class="external" target="_blank" rel="noopener noreferrer">this</a> implementation for ESP8266 modules to my ESP32. All credit for the algorithm belongs to them. Much of the heavy lifting of acquiring, interpreting, and rendering data from different data sources is performed on the microcontroller using less than 512 KB of memory. The embedded software that makes that possible is written in C -using the ESP-IDF v5.2.1. My e-paper display driver is a port of Waveshare {{< -link src="https://github.com/waveshareteam/e-Paper" class="external" -target="_blank" rel="noopener noreferrer" >}}examples{{< /link>}} for Arduino +using the ESP-IDF v5.2.1. My e-paper display driver is a port of Waveshare <a +href="https://github.com/waveshareteam/e-Paper" class="external" +target="_blank" rel="noopener noreferrer">examples</a> for Arduino and STM32 platforms. I've been using Etlas daily (for a couple of hours on weekdays and all day on |