We covered Real Time Logic’s open-source lightweight Minnow Server for microcontrollers last year, and now the company has released another project: Barracuda App Server for ESP32.
This project is more complex and requires an ESP32 board with PSRAM to run such as boards based on ESP32-WROVER module with 4 to 8MB PSRAM. The Barracuda App server (BAS) comes with a Lua VM, and in complement with the LSP App Manager that facilitates active development on the ESP32 by providing a web interface.
The Barracuda App Server runs on top of FreeRTOS real-time operating system part of Espressif free ESP-IDF development environment.
The company provides instructions to build BAS from source, as well as the LSP (Lua Server Pages ) App Manager that links to the binary-only BAS library. The Linux version of the ESP-IDF is recommended, so in Windows, you should install the “Windows Subsystem for Linux” first. The source code for LSP App manager can be found in Github, and documentation on Real Time Logic website. The Barracuda App Server library has quite a few more features than just the Lua VM as shown in the above diagram. It is available for ESP32 and other targets as well, and as a product from the company, the source code is available under a commercial license.
The video above shows how you can flash the LSP App Manager demo code to the board to control a server. After the initial setup, everything can be done in the web browser from editing Lua code to control the servo via WebSockets, to loading a trusted TLS certificate from Let’s Encrypt.