Joint Solution Brief

Background and Challenges

Kajima Corporation, one of the top construction companies in Japan, has been at the forefront of innovation in the construction industry ever since its inception in 1840.

The Yokohama branch of Kajima Corporation was exploring possible solutions aiming to improve the efficiency of “checking window closures” at condominium construction sites. At construction sites for condominiums and buildings, it is always necessary to check that the building’s windows are closed at the end of each day, but to check whether the windows are closed, it is necessary to go directly to each room on each floor and visually check. This task is crucial not only for security and environmental control but also to prevent damage from external elements like rain and wind. For condominiums with several hundred units or more, this work alone takes more than an hour; therefore, the burden of daily checks and rechecks during bad weather on site personnel, has become a major issue.

Moreover, the construction industry in Japan, faces additional challenges with a declining labor force and a push towards work style reforms aimed at reducing working hours, set to be enforced in April 2024. The necessity to optimize repetitive and laborious tasks has therefore become more critical than ever.


According to Mr. Shikata, the Kajima Corporation Yokohama branch Architecture Department Manager, Kajima conducted a comparative analysis of possible solutions and selected TED’s IoT Insight CaaS (which utilizes Cassia IoT gateway product) after discovering that the TED/Cassia solution is reliable, secure, low cost, and easy to deploy and manage.

Tokyo Electron Devices (TED) has proven to be the right partner for Kajima Corporation because of their long-standing commitment to innovation and a rich ecosystem of partners. TED, a major distributor of Cassia products in Japan, had already successfully partnered with Cassia Networks on developing IoT INSIGHT CaaS (Cassia as a Service) total solution and service. In collaboration with Cassia Networks, TED implemented a total solution including the industrial grade Cassia Networks X2000 Bluetooth gateway. X2000 gateway is weatherproof and made for outdoor use. Moreover, its multiple bi-directional connectivity and long range (extends Bluetooth connectivity up to 400 meters with Bluetooth 4 and up to 1 kilometer for Bluetooth 5 in open space) makes it ideal for a large construction-site environment with many obstacles.

Window Sensor

Cassia X2000 Gateway

The IoT INSIGHT CaaS total system was implemented at a condominium construction site in YokohamaBluetooth sensors were installed on the window frames of each apartment unit, and multiple Cassia X2000 Bluetooth gateways were placed strategically around the building perimeter. These gateways collected data from the sensors and transmitted it to the cloud environment (Microsoft Azure), where it was visualized and analyzed.


The TED/Cassia Networks total solution at the Kajima Corporation construction site led to a significant reduction in daily verification times by over 50 minutes. “After implementing CaaS, the status of the windows can now be checked in real time on mobile screens (via a dashboard), and if a window is detected as being left open, notifications can be sent to Microsoft Teams (twice a day at 16:00 and 17:00) allowing for quick responses,” commented Mr. Shikata.

Moreover, the system’s impact on worker motivation was notable. By reducing the tedious task of manual window checks, workers could focus more on their primary responsibilities, leading to increased job satisfaction and productivity. The ease of modifying the system’s dashboard in response to on-site needs, without the requirement for complex coding, also ensured that the system could adapt quickly to changing operational demands.

In summary the total solution brought immediate benefits:

Reduction in Manual Checks and cost: The time required for window checks was dramatically reduced from over an hour to less than three minutes, as the system allowed site managers to quickly review the status of all windows via a smartphone or computer.

Prevention of Damage: Automated alerts were generated if any window remained open, reducing the risk of interior damage due to weather exposure.

Operational Efficiency: By automating routine checks, site managers could allocate their time to more critical tasks, thereby improving overall site management and efficiency.

“After implementing CaaS, the status of the windows can now be checked in real time on mobile screens (via a dashboard), and if a window is detected as being left open, notifications can be sent to Microsoft Teams (twice a day at 16:00 and 17:00) allowing for quick responses.”
Mr. Shikata
Architecture Department Manager, Kajima Corporation Yokohama Branch


The deployment of the Cassia Networks X2000 Bluetooth gateway and TED’s IoT INSIGHT CaaS at Kajima Corporation’s construction site not only addressed the immediate operational challenges of window closure verification but also positioned Kajima to meet upcoming regulatory changes regarding work hours. This case study demonstrates the potential of IoT technologies to transform traditional construction practices, offering scalable, efficient, and cost-effective solutions that can significantly benefit the industry, particularly in times of labor shortages and stringent regulatory environments.



Cassia Networks is the leading provider of enterprise Bluetooth IoT products and solutions. Our patented technology provides the most reliable and easy to manage long-range, multiple device connectivity, edge-processing and locationing for Bluetooth IoT networks. Our mission is to solve the IoT connectivity, locationing and management challenges faced by today’s enterprises and make IoT easy.

To learn more about Cassia’s Bluetooth IoT products and solutions, please visit or contact us at

For more information about Tokyo Electron Devices, please visit their website.

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