ticker-tape🧾

This project leverages embedded rust support (std library) for the ESP32-S2 microcontroller and MAX7219 LED dot display to create a Wi-Fi enabled ticker-tape. Upon boot, the device will:

1. Connect to a local Wi-Fi network (credentials supplied by the user).
2. Advertise the IP address leased by the DHCP server on the ticker display.
3. Start a http server at the aforementioned IP.

Interaction with the ticker-tape display over Wi-Fi is possible with http GET/PUT commands.

Features

This project features:

• Using std embedded rust to control an ESP32-S2 microcontroller. It showcases the logic required to obtain a connection to an access point (AP), start a http server, register multiple http endpoints, and re-establish Wi-Fi connectivity upon link disconnection. All using the std crates provided by espressif!

• Driving the MAX7219 display, converting raw text to displayable patterns on the 8x8 LED grid.

Environment setup

Espressif toolchain

To be able to build and deploy this project to your local ESP device, espressif requires the following tools/packages to be available in your local development environment.

Cargo (rust) dependencies:

$ cargo install cargo-espflash espflash ldproxy

System dependencies:

$ apt install llvm-dev libclang-dev clang libuv-dev libuv1-dev pkgconf python3-venv python-is-python3

For further elaboration, please see the espressif std training manual.

Specify network credentials

Create a file called cfg.toml in the root of this repository. The contents need to be substituted with your specific network details.

$ touch cfg.toml
$ cat cfg.toml
[ticker-tape]
wifi_ssid = "<your wifi ssid>"
wifi_psk = "<your wifi psk>"

Hardware

The hardware required for this project:

• ESP32-S2: ESP32-S2 is a highly integrated, low-power, single-core Wi-Fi Microcontroller SoC, designed to be secure and cost-effective, with a high performance and a rich set of IO capabilities.
• MAX7219: Daisy-chainable 8x8 LED dot matrix.

Pin connections from the MAX7219 to the ESP32 are as follows:

MAX7219	ESP32-S2
Vcc	5V
GND	GND
Din	GPIO0
CS	GPIO1
CLK	GPIO2

Build and deploy

Once the necessary tooling has been installed, building this project should be as simple as running the following from the root of this repository:

$ cargo build

To deploy the built binary to the ESP32-S2, connect it to your local machine (with a serial cable) and execute the following:

$ cargo run
   Compiling ticker-tape v0.1.0 (/home/andrew/projects/ticker-tape-rs)
    Finished dev [optimized + debuginfo] target(s) in 6.37s
     Running `espflash flash --monitor target/xtensa-esp32s2-espidf/debug/ticker-tape`
[2023-12-26T06:24:16Z INFO ] 🚀 A new version of espflash is available: v2.1.0
[2023-12-26T06:24:16Z INFO ] Serial port: '/dev/ttyUSB0'
[2023-12-26T06:24:16Z INFO ] Connecting...
[2023-12-26T06:24:16Z INFO ] Using flash stub
Chip type:         esp32s2 (revision v0.0)
Crystal frequency: 40MHz
Flash size:        4MB
...
I (808) ticker_tape::wifi: Scanning for AP
...
I (55778) wifi:AP's beacon interval = 102400 us, DTIM period = 2
I (56618) esp_netif_handlers: sta ip: 192.168.114.121, mask: 255.255.255.0, gw: 192.168.114.91
I (56618) ticker_tape::display: Set ticker-tape message: "192.168.114.121"

Configuring the ticker display over Wi-Fi

Set the ticker display message:

$ curl -X PUT http://192.168.114.121/message -d "Hello World"

Set the scroll speed (ms):

$ curl -X PUT http://192.168.114.121/speed -d "40"

Set the brightness (%):

$ curl -X PUT http://192.168.114.121/brightness -d "50"

Get the current settings from the device:

~> curl -X GET http://192.168.114.121/ -w "\n"
{"message":"Hello World","speed":40,"brightness":50}