Project Sidegrade

Oh my god make it stop

Sidegrade is the fourth rendition of a piece of digital signage employed at Computer Science House to advertise events happening in special rooms.

The project consists of two parts: The Hardware, and The Proxy.

Hardware

The Hardware consists of an ESP32 and a 2004 display. The ESP32 has no headers, and the 2004 comes with an i2c adapter board. Using the provided Amazon links at time of writing it costs about $34 to build. It will also require soldering supplies, four 90° male pin headers, some wire, and four M3*16 machine screws.

Solder the following pins together, with the ESP32 facing away from the LCD. Leave some slack so that you can manipulate the two halves of the case later (ESP32 mounts in the back, 2004 Display mounts in the front)

Print the case. It shouldn't matter what filament is used.

Place the ESP32 on the pegs on the bottom case. Place the LCD on top of that and get the wires situated. Then, put the top case on and use the screws to fasten the top case, LCD, and bottom case together.

The firmware is written in Rust using tools from the excellent esp-rs project. It connects to a WiFi network, and periodically queries the proxy for text to display on the screen. It is chiefly used to display events from the Google Calendar API. The first row is used to display the name of the event, scrolling if necessary. The second row is used to display the time until the event, or the time left in the event.

Proxy

The Proxy is a simple webserver written in Rust using Actix Web. It serves the routes, unenecrypted, that the Hardware checks to get event information. The location of interest (i.e. where the device is installed) is configurable.

Routes

/locations/<location>/event

Queries the Google Calendar API for events, then looks for the next event that is happening, parsing the response and formatting it for the display. Example:

History
In 00:15:23

Development

Install Rust and follow the guide available in The Rust on ESP Book.

Specifically, this page is how you install for Xtensa platforms.

In the root of this project, run:

cargo install espup
espup install
cargo install ldproxy
cargo install espflash

These pages will probably be useful:

• https://github.com/esp-rs/esp-idf-hal
  • The Hardware Abstraction Layer library for ESP. Implements embedded-hal.
• https://github.com/esp-rs/esp-idf-svc
  • Wrappers for abstracting some of the more complex featuees of the ESP32, such as WiFi and HTTP requests.

Deployment

The Hardware

Plug in your ESP32, then run:

cargo run

If you just want to get serial output, you can do:

cargo espflash monitor

The Proxy

Fill out the .env file. Then,

podman build . --tag fuckoff4-proxy
podman run --rm -e .env --name fuckoff4-proxy fuckoff4-proxy