Building and Certifying an Open-Source IoT Controller, Part 1

Open-source projects—both hardware and software—are commonly associated with people working in the garage for the sake of having fun. However, some great open-source projects are also created for the purpose of commercial enterprise. This article begins a four-part series on the development of one such project, an open-source Internet of Things (IoT) hardware platform known as the Anthilla Controller (or AnthC, for short).

The goal of the series is to provide insight into how a new open-source hardware product is brought to fruition. In the first article, we’ll focus on the AnthC project’s genesis and its design requirements. Subsequent articles will cover:

• Obtaining the Open Source Hardware certification.
• Testing and manufacturing.
• Meeting legal requirements for sale in the intended market.

Project History

The project began in 2021, with a list of requirements put together collaboratively by Italian IT services company Anthilla and the designer Esteban Corredor. Anthilla sponsored the project’s initial development, and Esteban Corredor designed and built the first version of the board. Once they had proof of concept, they searched for contributors who could help them bring the product to market.

It was at this point that I joined the project team. The version of the project I helped develop, the Anthilla Controller M2-R3, is the one we’ll be discussing in this and subsequent articles. Some of the technical features listed in the next section are specific to this version.

The Anthilla Controller’s design, manufacturing, and assembly files are available for download on the repository web page.

Key Features

One key aspect of the AnthC is its modular design. Built around the ESP32 microcontroller, the board provides a range of interfaces that can be expanded with additional modules. Functionalities such as sensors, relays, and displays can be added in this way.

The AnthC’s form factor is the same as a Raspberry Pi, so it’s possible to employ many mechanical and electrical components already available on the market. It’s important to note, however, that the electrical pinning of the Anthilla Controller (Figure 1) isn’t exactly the same as that of a Raspberry Pi. Please check your device’s manual before installing anything.

Figure 1. Anthilla Controller board. Image used courtesy of github

Below is an exhaustive list of the AnthC’s technical features:

• ESP32-S3 microcontroller.
• Bluetooth Low Energy.
• Wifi 2.4 GHz b/g/n.
• Input power: 7 V to 28 V. It’s possible to supply just the low voltage area of the board.
• 4 digital inputs.
• 4 analog inputs (16-bit ADC) or 4-20 mA inputs switchable (multiplexed).
• 6 open collector outputs.
• USB-C port for power and communications.
• I²C communication.
• SPI communication.
• RS485 communication.
• Real-time clock (RTC) with a coin-cell backup power source.
• RGB LED.
• Rechargeable LiPo battery.
• Extended temperature range.
• Transient voltage suppressors.
• Common-mode and differential filters.

This project, like many others at the time, was impacted by supply chain disruptions that resulted in a lack of components on the market. Many components needed to be replaced, requiring new tests and further verification. The manufacturing of the new version therefore occurred much later than expected.

In the next section, we’ll discuss another key feature of the Anthilla Controller: its open-source nature.

Why Open Source?

Open-source hardware projects often attract doubts. These doubts are mainly caused by fear, either of losing intellectual property or of losing a competitive advantage. However, Arduino, Raspberry Pi, and openBCI all stand as examples of successful open-source hardware development projects. Open-source projects have many advantages, including:

• Transparency and trust: Users can examine files, such as the controller’s electronic schematic or the PCB manufacturing files, to learn how the system works.
• Education: Related to the above, the project can be used as a learning tool for those wanting to learn about IoT and electronics. In the Anthilla Controller’s case, its ESP32 module is compatible with the Arduino platform, making the learning curve quite soft.
• Long-term support: New, different contributors can work on an open-source project even if the original authors are no longer involved. This means that the project can be maintained over the long term.
• Repairability: Users can perform maintenance tasks and repair broken systems themselves.

We decided to make the Anthilla Controller open source for all these reasons, as well as the following:

• To share knowledge, so that other designers can learn from any mistakes we make and reduce their learning curve.
• To reach as many people as possible, increasing opportunities to make an impact.
• To provide opportunities for the creation of related projects.
• To make the project attractive to the open-source community.
• To encourage collaboration within the open-source community.

With that in mind, we sought the Open Source Hardware certification for the Anthilla Controller M2-R3. This certification (Figure 2) shows that our project meets the community definition of open-source hardware. As an added benefit, it means that our product is listed in the Open Source Hardware Association’s global database of projects. 

Figure 2. The Open Source Hardware logo can be used by products with the appropriate certification. Image used courtesy of OSHWA

Next Steps

The above certification wasn’t the only one we needed to gain before the Anthilla Controller could be released. Both electromagnetic compatibility (EMC) and safety certifications are compulsory, and must be guaranteed by the legal manufacturer. In fact, these certifications are some of the biggest barriers when placing a new electronic project on the market.

Also, we intended the Anthilla Controller’s initial release for the European market, with expansion into other global markets to occur at a future time. To place a product in the European market, a manufacturer needs to affix the Conformité Européenne (CE) marking to their product. The steps to affix the label are:

1. Confirm that EMC and safety tests have been performed, and relevant certifications obtained.
2. Check any other legal requirements.
3. Build a technical file.
4. Write the declaration of conformity.

All of this will be covered in greater detail later. In Part 2, we’ll discuss the process of obtaining the Open Source Hardware certification.

Editorial note: The Anthilla Controller’s initial development, testing, and manufacturing was made possible by funding from Anthilla, but the company is not currently involved with the project. Neither All About Circuits nor the author of this article receive any financial benefit from Anthilla for the article’s publication.