The Internet of Things is growing and is not stopping at cities – as they too become smart. To ensure this takes place in the most harmonious and optically appealing manner, a Leipzig-based producer of light concepts is adopting new ways of transforming lampposts into charging stations. Above all, the electronics used must be robust, reliable and easily integrable.
They not only have to look good but also offer state-of-the-art functionality in a robust form. These were the aims behind the design process of the smart outdoor luminaire Pablo. The urban lighting with its modern shape reminiscent of cubism shows how cities can be digitized discreetly and urban spaces modernized sustainably. For the manufacturer, Leipziger Leuchten, the modern street luminaire marks the point of entry into the still young field of the smart city, the intelligent, connected urban space.
While LEDs in the outdoor luminaire are brightening up the streets, integrated Wi-Fi and video technology are not only helping to connect city and residents but also providing more security, in line with customer wishes. The optionally integrated charging station ensures that vehicle batteries remain fully powered. The charging unit called Karsten is controlled by a touchscreen integrated into the housing together with an embedded system. This module, known as a human machine interface (HMI), is a Santino LT, a standard product capable of customization from the Hamburg-based company Garz und Fricke. It comprises a display together with matching touch interface alongside the single board computer.
The Leipzig-based company was looking for a combination comprising display and control computer resistant to the weather, heat and even rough handling. Many companies supply only products that do not adequately protect the display and electronics. Garz und Fricke provided the Santino LT. It is an all-in-one module with a 5-inch touchscreen. Ensuring precise input is the capacitative touch interface, which with its multi-touch capability is also able to cope with more than one finger. The processor of the single board computer is an i.mx6 from NXP. Standard interfaces including USB 2.0 and other serial ports such as RS485 and RS232 round off the circuit board. These can be connected and integrated via modules such as RFID readers from the customer.
"We were looking for a display together with a control computer to meet our demands in terms of robustness when facing the weather, heat and even rough treatment. It wasn’t easy, and many companies were quickly ruled out because they were unable to offers sufficient protection for the display and the electronics. Not until we found Garz & Fricke did we have a supplier able to meet all our wishes."
The selection of capacitative touchscreen is almost inevitably a result of the requirements. It is also the only way to defy rough mechanical treatment. This is why the developers at Garz und Fricke rely on special, chemically hardened glass with a thickness of 2.8 mm, which withstands even industrial shock and impact tests. Another argument for capacitative technology is the high level of brightness and good legibility even in sunlight. Despite its superior robustness, the display in the Senso glass construction fitting flush with the housing also creates a good optical impression. However, the capacitative technology is not entirely straightforward in outdoor use. Raindrops, for example, may disrupt the recognition of inputs. The reason is to be found in the functional principle: when a finger contacts a capacitative touch surface, small electrical currents then flow, which the electronics use to determine the position of one or more fingers. The same also happens though when a raindrop falls onto the display. Low electrical currents flow in this case as well. Yet the developers in Hamburg have found a way to get round this unwanted behaviour. They tackle the problem at software level and classify static signals or those with minimal movement in the driver software as “non-fingers”. The disruptive signal is then separated out. Afterwards the display control now merely converts signals into inputs when something on the surface moves significantly.
One challenge for both the display and the electronics of the Santino LT (equipped with a ARM Cortex - A9 processor) is posed by great heat, as quickly builds up in bright sunlight during outdoor applications. The solution for this starts with the hardware. Critical assemblies with high current consumption such as the CPUs or working memory are cooled with specially developed, individually adapted, injection-moulded aluminium heat sinks. In addition, the display has been thermally isolated and conducts part of the dissipated heat directly into the cover plate of the screen, which again results in a few degrees of cooling. If these measures still do not suffice on an especially hot day, a further solution can be found at software level. In such cases, the operating system deliberately reduces the computing speed of the embedded system or dims the display, which leads to less waste heat being generated by the system itself.
Customers have a choice of operating system for the Santino LT between an embedded Windows, Android or Yocto-Linux. Generally the decision is made in favour of the flexible and powerful Yocto. Strictly speaking, though, Yocto does not represent a separate Linux distribution but instead a self-service ecosystem for developers. Yocto stands out particularly due to its standardized architecture and high level of adaptability. The Yocto specifically optimized by the Hamburg supplier to the board and the purpose of the application includes the QT graphics framework. Version 5, which is used here, can be programmed on the basis of QML and partly even on HTML, which facilitates the creation of applications. Also of assistance in providing a quick and effective introduction to working with the Santino LT is the extensive information on the platform. Along with comprehensive documentation of the product and interfaces, detailed release notes are additionally provided. These notes list the changes that have taken place in the system code and contain full references to the software components and licences used.
There is also transparency in matters of already familiar but yet to be remedied errors in the code. The documentation is completed with a list of all tests performed. This collection of information is a useful tool for the developers in the company implementing the solution and help in the subsequent certification of the resulting products into which the Garz und Fricke assemblies have to be integrated.
Leipziger Leuchten sees the Santino LT as a compact solution for integrating technologies such as charging stations directly into the street furniture. On the one hand, the Leipzig-based company simultaneously has the practical benefits for the user in view. On the other hand, there is a desire to modernize the public space without, for example, obstructing it with a large number of new columns and bollards. Instead, the aim is to utilize the available space better and more efficiently.
The smart city and the Internet of Things (IoT) are evolving into an exciting and lucrative business field. For the two cooperating companies, the Internet of machines and sensors is one of those business fields that are already important and are set to become even more so in the future. Even now, for example, the Hamburg-based company is connecting many of its systems with its own cloud solution. In doing so, it relies on secured transport routes for the data, firstly, in order to guarantee undisturbed operation but also to guarantee data security.
Of particular importance for manufacturers of durable goods such as connected street furniture, are long-term availability and a stable supply of the components used. This is because assemblies often disappear from the supplier’s range far too quickly and are replaced by completely different versions. Garz und Fricke is aiming to rule this out through the durability of its lamps. Generally they are not replaced until they have completed several years of service. Accordingly, the suppliers of connectivity and control solutions should be able to demonstrate an obsolescence management strategy. During the purchasing process, for example, the company from Hamburg makes sure that the components and systems are available in the long run. This eliminates time-consuming redesign processes and means that unreliable and excessively expensive component sources can be avoided. Garz und Fricke only withdraws products from its range if a successor product is available that fits equally well and can be integrated just as easily.
A solution was found with the Santino LTembedded system of making street furniture fit for the smart city and the Internet of Things (IoT) in an easy and lasting way. An important aspect of this is the challenge of planning the supply of components used over a longer period of time.