Strandbutler: Know Where Your Beach Chair Awaits You
IoT Blog
Strandbutler: Know Where Your Beach Chair Awaits You
04.07.2025by
Kerstin Koch
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Book it and forget the search: How Telekom’s IoT and nuSIM technology helped a startup to re-invent the beach chair experience on the North and Baltic Sea coast.
Booking a beach chair may sound like a vacation in itself but it can at times be a real challenge. You hope there’ll be someone at the booking hut. You stand in line, have cash at the ready and try to find the right wicker chair among, say, a hundred. Some years ago Bernhard Sourdeau experienced at first hand on the North Sea island of Föhr just how difficult renting one of Germany’s distinctive wicker beach chairs off the cuff can be, and that experience led to the idea of the Strandbutler. Sourdeau, back in Hamburg, founded a startup, Strand & Mehr. He and his team developed a solution that digitized the rental process.
Fast Track to Your Beach Chair of Choice: A Digital Solution for the Rental Process
Around 100,000 beach chairs along Germany’s North and Baltic Sea coast spelled business potential for his team of soft- and hardware experts. “From the outset it was clear to me that we would need both a software platform and a hardware component—the lock,” CEO Sourdeau says. The toughest challenge was to develop a robust lock for the beach chairs, one that was suitable for use in harsh coastal conditions. After a number of trial runs Strand & Mehr collaborated with a Chinese manufacturer in adapting its basic model to the specific requirements.
“Our initial idea,” Sourdeau says, “was to use Bluetooth to open the lock with a cellphone.” In addition to Bluetooth, Strandbutler offers RFID chips as an alternative opening method for visitors who prefer not to take their cellphone with them to the beach. In collaboration with beach chair operators, Strand & Mehr then set up a digital rental platform. Tourists can use an app prior to their vacation to book a beach chair in their chosen area of the beach and use it on the spot once they arrive at their destination.
The locks that were used to secure the beach chairs were initially equipped with just a button battery that as a rule lasted for the vacation season but had to be replaced annually. As the number of beach chairs managed in this way increased, that posed a logistical challenge. “With 5,000 locks that is a whole lot of work every year,” Sourdeau explains. An integrated solar cell and battery now ensures operating times without a change of battery, thereby reducing maintenance costs substantially.
The Digital Lock: Sophisticated Technology with a Cellphone Link
The company worked continuously to improve the lock. A decisive step in its further development was connecting it to the Internet of Things (IoT) and integrating Telekom’s nuSIM technology (see Infobox). The cellular SIM delivers a number of advantages that greatly improve the beach chair lock’s management and functionality. The nuSIM enables remote location of locks, helping beach chair operators to retain an overview of their chairs. If assistance is required because, for example, a lock cannot be opened, it can be opened remotely if the customer notifies the provider on the app.
Connection to Telekom’s cellular network also facilitates comprehensive remote maintenance that includes reading important device data such as the battery charge level. Supported by both LTE and NarrowBand IoT, the system can be adapted flexibly to the best reception situation. A further benefit is space-saving integration without an additional SIM card slot. That makes the lock even more compact.
Last not least, fewer apertures in the casing makes the lock more resistant to harsh coastal weather conditions due to sun, salt, sand, and water. The latest generation of locks even uses GPS positioning to locate beach chairs precisely—a further improvement in beach chair management. And nuSIM, especially in combination with the NB-IoT wireless standard, uses very little energy, a perfect prerequisite for long battery life.
nuSIM—The Integrated SIM for the Internet of Things
nuSIM is an innovative Telekom iSIM solution that integrates the SIM card’s functions in the communication chip. That makes the technology …
Cost-efficient: no separate SIM card, no SIM holder, lower logistics costs
Energy-saving: up to 90% less power consumption
Compact: space-savingly ideal for small IoT devices
Robust: perfect protection from moisture, dust, and external influences
Secure: TÜV IT certified and protected from manual access
Flexible: online provision of SIM data and OTA updates
These technical innovations enable Strand & Mehr to offer a reliable and user-friendly beach chair rental system. The company currently manages more than 10,000 beach chairs at over 70 locations from Borkum to Usedom. Around 5,000 are already equipped with the smart locks.
nuSIM: A Customized Solution with Potential for Expansion
The decision to partner with Telekom was of strategic importance for Strand & Mehr. “In principle, nuSIM was perfect because it could be fully integrated—built in—to our lock,” CEO Sourdeau says. In contrast to ready-made hardware solutions from other providers that were often too big, too expensive, or came with unnecessary functions, Telekom’s nuSIM technology delivered the flexibility that the startup needed.
“Close collaboration with Telekom enabled us to offer a customized solution that did justice to the specific requirements of the beach chair rental business,” Sourdeau says. Telekom’s global presence and the reliability of its cellular and IoT networks were for Sourdeau further factors that were crucial for Strand & Mehr’s choice, especially in view of potential future expansion.
Strand & Mehr is already considering further uses. “At Digital X 2023, where we had a beach chair on show, a cruise operator contacted us,” Sourdeau says. “Our smart lock could, for example, be used to lock and manage the rental bikes that travel companies often offer for hire when cruise passengers go ashore at their destinations.” Beach loungers and parasols in southern vacation countries could be another scenario.
„Close collaboration with Telekom enables us to offer a customized solution.“
Bernhard Sourdeau, Founder and CEO, Strand & Mehr GmbH
In addition, Telekom now even offers to integrate satellite connections in future chip generations. That might extend possible uses to remote areas or the high seas, such as on a cruise ship. “It might even be possible to order drinks or snacks from a beach chair via the app,” Sourdeau says. “We then really would have a beach butler.”
IoT SIM and tariffs
IoT SIM and tariffs
With Deutsche Telekom’s IoT platforms, you always stay in control of your connected devices, data, and connections. Whether it’s SIM card management, data analytics, or device control – our solutions offer centralized visibility, efficiency, and security across your entire IoT ecosystem.
With Deutsche Telekom’s IoT platforms, you always stay in control of your connected devices, data, and connections. Whether it’s SIM card management, data analytics, or device control – our solutions offer centralized visibility, efficiency, and security across your entire IoT ecosystem.
Since 2016, Kerstin has been part of the IoT journey at Deutsche Telekom. Over the years, she has supported numerous marketing and cultural projects – always with the goal of making IoT tangible and relevant. She translates complex topics into clear, user-focused language and puts real customer success stories front and center. In the IoT blog, she highlights selected use cases and references, showing how companies create measurable value with IoT.
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