With the introduction of powerful and affordable SoCs (system-on-chip) featuring integrated Wi-Fi and Bluetooth about 10 years ago, the Internet of Things (IoT) began to come within reach. Over the years, the quantity and, above all, the quality of available development frameworks have increased significantly, making it possible to implement sophisticated applications in the industrial sector using the IoT device platforms available today.
At the same time, there is a wide selection of development boards for every conceivable application, ranging from monitoring environmental conditions to recording medical parameters, providing intuitive HMIs (human-machine interfaces), and performing audio processing, speech recognition, and image analysis. This offering is rounded out by a range of miniaturized and easy-to-control sensors, some of which are byproducts of smartphone development. This provides companies that previously could not overcome the market entry barrier of developing their own hardware with the opportunity to offer innovative products combining hardware and software.
Of course, there are a few hurdles to overcome on the path to becoming an integrated provider of hardware and software. While software requirements are practically second nature to us, we must take into account a number of technical and legal considerations when selecting hardware.
Technical and Legal Framework
One key point is the Environmental Conditions at the planned deployment site of the IoT device. These factors determine the effort required to protect the devices and enhance their reliability.
Especially when the devices are installed for an extended period, the Maintainability and Repairability of crucial importance. Fault analysis and the replacement of defective components can be optimized to save time and money.
In the field of Energy Supply There is a wide range of options available for various application scenarios. In most cases, data communication accounts for a large portion of energy consumption, while modern sensors operate on very low currents. Depending on data volume and communication cycles, as well as network availability and device location, creative solutions are needed here.
A computer equipped with sensors becomes an IoT device only through the Network Connection. This ensures that the collected data reaches the backend of the overall application with only a slight delay. Here, too, there are various technologies, each with its own specific advantages and disadvantages.
An existing network connection enables the implementation of Remote Software Updates. This allows both bug fixes and new features to be made available on IoT devices quickly and cost-effectively.
Last but not least, there are also the Security as well as the field of legal framework in the context of product liability and certification.
Environmental Conditions
Unlike in controlled laboratory settings, industrial environments tend to have harsh conditions. Temperatures fluctuate with the seasons. High humidity causes leakage currents, corrodes materials, and reduces the range of radio signals. Machines generate constant vibrations. The devices must be able to withstand various (accidental) mechanical stresses, such as impacts, shocks, and—in particular—cable tugging. These challenges can be addressed by using enclosures with the appropriate protection rating (IPxx) and impact resistance (IKxx), as well as sturdy cable fastenings and strain reliefs.
Maintainability and Repairability
Even during the design phase, one should consider the maintainability and repairability of the equipment. Once installed, some of the equipment is located in hard-to-reach areas. Due to the nature of their mounting, equipment components and cabling are no longer as easily replaceable. A modular design (with pluggable cables and subcomponents) can significantly reduce repair efforts. This requires the availability of the most comprehensive fault diagnosis possible at the installation site. The use of an integrated display has proven to be quite helpful. This allows the devices to be configured at the installation site, and later on, technicians can isolate and resolve many issues on-site without additional equipment or extensive training. Relevant parameters include the signal strength of network connections, the connection status to the backend, and key metrics from connected sensors. In addition, we have integrated a Wi-Fi-accessible maintenance console into our IoT solutions, which allows all configuration parameters to be modified and provides information about the current status of the running software components (e.g., log messages, data rates, processor utilization).
Energy Supply
A stable power supply is the foundation for reliable IoT devices. If mains power can be routed to the vicinity of the sensor with reasonable effort, the use of a power supply unit has proven effective. Mobile sensors can be powered by batteries or rechargeable batteries (for very low power consumption), solar cells (outdoors only), or small generators. It is important to note that devices with cellular or Wi-Fi communication experience brief power spikes that can be many times the normal current draw. If the power supply cannot deliver this power, the integrated brownout detection causes the processor to shut down in a controlled manner (and, depending on the configuration, to restart once sufficient voltage is restored) to prevent unwanted malfunctions. Unexpected reboots do not always indicate software errors; sometimes, even a properly functioning power supply can cause them.
Network Connection
IoT devices can be connected to the network using a variety of technologies. The most independent solution is to use a built-in cellular connection, provided that network coverage allows it (take care with metal roofs and wall cladding, as well as larger metal fixtures). However, this can become quite costly over time when dealing with large amounts of data or a large number of sensors.
Wi-Fi is ideal for higher data rates and longer distances within buildings. To ensure optimal performance, there should be no metal parts between the device’s antenna and the access point that could interfere with the wireless connection. For PCB antennas (integrated into the device’s circuit board), the distance should remain under 30 meters. When there are a large number of devices, bottlenecks can occur in the Wi-Fi network; in this case, Bluetooth can be used as an alternative. Bluetooth offers a shorter range and lower data rate, resulting in less interference with other devices. Lack of network coverage can be compensated for by installing additional gateways. A key advantage of Bluetooth is its low power consumption, which opens up alternative power supply options.
Last but not least, a wired Ethernet connection is an interesting option, especially when data transfer rates and connection stability are the top priorities. The downside is the significant installation effort required.
For all options except mobile connectivity, integrating the IoT devices into the company network is typically required. Due to the high security requirements for production-critical IT infrastructure, accessing a cloud provider via the Internet, for example, is not readily possible. In addition to the need to configure the devices to allow access to selected destination addresses, access to the Internet often occurs via a proxy that permits communication only through HTTP/HTTPS ports. The MQTT protocol, which is commonly used in the IoT sector, cannot communicate directly through these ports, whether unencrypted or with TLS encryption. As a workaround, the encrypted MQTT connection can be tunneled via WebSockets.
Software Updates
In practical use, the ability to update devices is an important criterion. The more complex an IoT device’s software is, the more likely it is that bug fixes or new features will be needed later on. However, updates via USB cable are very time-consuming because each device must be physically accessed. A remote update feature (FOTA = Flash Over The Air) provides a solution, allowing large numbers of devices to be updated with new software versions relatively easily over the Internet. To ensure that only authorized firmware is installed, the software package must be digitally signed so that it is accepted by the device.
Security
IoT devices are not typically housed in a highly secure data center, which means there is a risk of unauthorized physical access. On the one hand, this poses a security risk, as communication keys and passwords could be intercepted and subsequently used to launch attacks on the network infrastructure. On the other hand, there is a need to protect the intellectual property rights associated with the installed software.
The solution is to implement device-level encryption that ensures attackers can only obtain worthless data garbage. To achieve this, after the device is initially flashed, the flash memory (code and data) is encrypted using hardware-based encryption. The key is device-specific, cannot be read, and cannot be modified (stored in so-called eFuses). Since the encryption cannot be disabled, this prevents the extraction of usable information from the flash memory.
Legal Requirements
Even if you simply install off-the-shelf development boards into a case, you are considered the manufacturer or distributor of these devices and are therefore responsible for product safety. The purpose of product safety regulations is to ensure an adequate level of protection for consumers and commercial users. In the case of hardware you have assembled yourself from pre-certified components, at a minimum, the Product Safety Act and the CE Directives apply.
On the one hand, applying existing legal regulations provides useful guidance in the development of new products, reduces liability risks, and is a prerequisite for placing products on the market in certain markets and for obtaining product liability insurance. On the other hand, safety requirements result in additional costs and restrictions on product design, as well as a slower pace of innovation.
Conclusion
The availability of mature IoT platforms lays the foundation for a range of new application scenarios in the industrial sector that were not economically feasible just a few years ago. Now that control technology has already been largely automated, the focus is shifting to monitoring the status of technical equipment as the basis for maintenance planning and forecasting. This frees staff from routine inspection rounds and measurements, allowing them to concentrate fully on maintenance.
For companies that are well-positioned in the fields of software development and data science, this offers an outstanding opportunity to provide „all-in-one“ solutions tailored to specific Industry 4.0 challenges, provided the necessary IoT sensors are included in the package. This can be achieved in collaboration with appropriate partners, but it is also possible to do so independently, provided certain technical and legal requirements are met.
