Note: The arduino-sdk repository showcased in this post is deprecated. GoliothLabs has two experimental repositories that may work as replacements:
In this post and associated video, we’re talking about interfacing hardware to Golioth using popular tools like PlatformIO and Arduino Core (API). Alvaro shows how to use an ESP32 board from Adafruit with the Arduino Core on PlatformIO to talk to the Golioth MQTT endpoint. Golioth has a range of tools and resources for hardware and firmware engineers to get their devices talking to the cloud.
PlatformIO is a plugin system built on top of VS Code that enables embedded developers to get up and running quickly with different Real Time Operating Systems (RTOS), chipsets, and boards. There is a library manager to help manage dependencies within projects, which removes much of the friction at the beginning of development projects. Currently they do not support Zephyr for ESP32 (a combination previously shown on this blog/channel), but they do support things like the ESP-IDF (based on FreeRTOS) and the Arduino core. Once you pull in the project files from the Golioth Arduino SDK page, PlatformIO will try to download all of the dependencies required to build firmware for a particular board.
What is Arduino Core?
The Arduino Core refers to the APIs that are available on different hardware devices in order to conform to the Arduino ecosystem. In the example below, it refers to Espressif’s Arduino Core port, which means that the ESP32 functions will align with what the Arduino IDE might be asking of that hardware. If you are using platforms outside of the Arduino IDE, you can still interact with many of the underlying functions that were written by hardware and firmware developers to make boards work with Arduino software.
PlatformIO also pulls in other libraries that are useful for processing data coming out of the hardware, such as the Arduino JSON library. So while it’s not the “teal and white IDE” that many people expect, it’s utilizing much of the same work that enabled people to work from within the IDE.
Golioth’s MQTT endpoint
MQTT is now available in preview on Golioth, but should have a similar user experience as other protocols on the platform. Since the early days of Golioth, we have offered device services over CoAP. We chose CoAP as a first offering because it is meant for low-power devices in potentially lossy environments, like cellular networks. MQTT is a popular transport protocol that many engineers use to initially connect their devices to the internet, only to need additional tooling on other platforms. From Golioth’s standpoint, the user doesn’t need to care about which one they’re using. Instead, we provide device services like LightDB, which allows the user to push and pull configuration data and state-based sensor readings from a device. LightDB stream allows for time-series data that needs to be aggregated and displayed on something like a chart. Golioth has other features like firmware updates and logging, that also operate over these protocols.
In the video below, Alvaro shows how the new MQTT endpoint and services from Golioth enable a similar experience that is shown using CoAP in other demos on the platform. What is different now is that we can utilize code from other platforms like Arduino Core, which already had MQTT libraries built-in. Alvaro showcases how he was able to quickly build an Arduino SDK for the Golioth Labs GitHub.