What is Amazon FreeRTOS and why should you care?

At Nordcloud, we've been working with AWS IoT since Amazon released it

We've enabled some great customer success stories by leveraging the high-level features of AWS IoT. We combine those features with our Serverless development expertise to create awesome cloud applications. Our projects have ranged from simple data collection and device management to large-scale data lakes and advanced edge computing solutions.  

In this article we'll take a look at what Amazon FreeRTOS can offer for IoT solutions

First released in November 2017, Amazon FreeRTOS is a microcontroller (MCU) operating system. It's designed for connecting lightweight microcontroller-based devices to AWS IoT and AWS Greengrass. This means you can have your sensor and actuator devices connect directly to the cloud, without having smart gateways acting as intermediaries.

What are microcontrollers?

If you're unfamiliar with microcontrollers, you can think of them as a category of smart devices that are too lightweight to run a full Linux operating system. Instead, they run a single application customized for some particular purpose. We usually call these applications firmware. Developers combine various operating system components and application components into a firmware image and "burn" it on the flash memory of the device. The device then keeps performing its task until a new firmware is installed. Firmware developers have long used the original FreeRTOS operating system to develop applications on various hardware platforms. Amazon has extended FreeRTOS with a number of features to make it easy for applications to connect to AWS IoT and AWS Greengrass, which are Amazon's solutions for cloud based and edge based IoT. Amazon FreeRTOS currently includes components for basic MQTT communication, Shadow updates, AWS Greengrass endpoint discovery and Over-The-Air (OTA) firmware updates. You get these features out-of-the-box when you build your application on top of Amazon FreeRTOS. Amazon also runs a FreeRTOS qualification program for hardware partners. Qualified products have certain minimum requirements to ensure that they support Amazon FreeRTOS cloud features properly.

Use cases and scenarios

Why should you use Amazon FreeRTOS instead of Linux? Perhaps your current IoT solution depends on a separate Linux based gateway device, which you could eliminate to cut costs and simplify the solution. If your ARM-based sensor devices already support WiFi and are capable of running Amazon FreeRTOS, they could connect directly to AWS IoT without requiring a separate gateway. Edge computing scenarios might require a more powerful, Linux based smart gateway that runs AWS Greengrass. In such cases you can use Amazon FreeRTOS to implement additional lightweight devices such as sensors and actuators. These devices will use MQTT to talk to the Greengrass core, which means you don't need to worry about integrating other communications protocols to your system. In general, microcontroller based applications have the benefit of being much more simple than Linux based systems. You don't need to deal with operating system updates, dependency conflicts and other moving parts. Your own firmware code might introduce its own bugs and security issues, but the attack surface is radically smaller than a full operating system installation.

How to try it out

If you are interested in Amazon FreeRTOS, you might want to order one of the many compatible microcontroller boards. They all sell for less than $100 online. Each board comes with its own set of features and a toolchain for building applications. Make sure to pick one that fits your purpose and requirements. In particular, not all of the compatible boards include support for Over-The-Air (OTA) firmware upgrades. At Nordcloud we have tried out two Amazon-qualified boards at the time of writing:

• STM32L4 Discovery Kit
• Espressif ESP-WROVER-KIT (with Over-The-Air update support)

ST provides their own SystemWorkBench Ac6 IDE for developing applications on STM32 boards. You may need to navigate the websites a bit, but you'll find versions for Mac, Linux and Windows. Amazon provides instructions for setting everything up and downloading a preconfigured Amazon FreeRTOS distribution suitable for the device. You'll be able to open it in the IDE, customize it and deploy it. Espressif provides a command line based toolchain for developing applications on ESP32 boards which works on Mac, Linux and Windows. Amazon provides instructions on how to set it up for Amazon FreeRTOS. Once the basic setup is working and you are able to flash your device, there are more instructions for setting up Over-The-Air updates. Both of these devices are development boards that will let you get started easily with any USB-equipped computer. For actual IoT deployments you'll probably want to look into more customized hardware.

Conclusion

We hope you'll find Amazon FreeRTOS useful in your IoT applications. If you need any help in planning and implementing your IoT solutions, feel free to contact us.