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Bluetooth® technology is transforming the way we use smartphones, turning them into convenient and secure digital keys for various applications. With 515 million location service devices projected to ship annually by 2027, increased adoption is being driven by a heightened awareness of the benefits and capabilities of Bluetooth positioning solutions.

LIXIL, a renowned name in Japan’s building and housing industries, has embraced Bluetooth technology as their solution of choice for their innovative FamiLock household digital keys. By leveraging Bluetooth technology’s wide smartphone adoption, energy efficiency, and robust security, LIXIL developed a product that allows users to effortlessly lock and unlock doors using their smartphones. I recently had an opportunity to speak with Mr. Hidetada Sakai from LIXIL Housing Technology’s Sash & Door division about the development of this technology.

Q&A With Hidetada Sakai From LIXIL

How does the FamiLock solution utilize Bluetooth technology to differentiate from other similar smart home solutions in the market?

For many years, locking and unlocking front doors has traditionally been done with mechanical keys. Recently, however, demand has increased for improved user operability, which has led to the use of smart entry keys such as cards and remotes that enable one-touch operation.

By utilizing Bluetooth® technology, we were able to achieve our goal of enabling locking and unlocking via smartphone from inside a pocket.

In this context, we have been developing a product that eliminates the need to carry a dedicated key specifically for the home by enabling personal smartphones to be used instead. Given how common it is for one’s hands to be occupied upon trying to enter one’s home, the act of taking a key out from a bag or pocket can be very inconvenient. We believe that true convenience lies in the ability to work locks via a smartphone from inside one’s pocket. For this purpose, the communication standard that we were to use needed to be widely incorporated in smartphones and energy efficient, have a controllable authentication range, and address security concerns.

Bluetooth® technology was essential to fulfilling each and every one of these conditions and was our first-choice technology. By utilizing Bluetooth technology, we were able to achieve our goal of enabling locking and unlocking via smartphone from inside a pocket, and we have received favorable feedback to the introduction of the industry’s first FamiLock.

Why did you choose Bluetooth technology over other wireless technologies?

When considering how to make the smartphone as a front door key concept into reality, we were aware of alternatives to Bluetooth® technology, such as NFC and Wi-Fi. NFC would allow for unlocking and locking after a smartphone’s battery has died, but its short communication distance requires that the smartphone be removed from one’s pocket and held in front of the door, which is an inconvenience that we were hoping to avoid.

Bluetooth® technology has proven to be the best solution as it has a wider range than NFC and is more power efficient.

While Wi-Fi allows for authentication over a wider range than NFC, it was not possible to adopt it for use as a smart entry key technology as it consumes a large amount of power, and door-side batteries would not last as long as they need to as a result.

Bluetooth technology has proven to be the best solution as it has a wider range than NFC and is more power efficient (thanks to Bluetooth Low Energy). It is also a technology with a household name that has seen a wide variety of technical achievements. We ultimately adopted Bluetooth technology, confident that it will continue to be in use for a long time to come.


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Are there any examples that you can share where this solution was successfully applied?

We developed and introduced FamiLoc with the goal of achieving smooth locking and unlocking without the necessity of procuring the key or smartphone from where it is being kept, similar to smart entry keys used in vehicles. While it is common for smartphones to be used as keys, there are few technologies that have achieved the same level of ease and convenience without any wasted time or awkwardness.

We achieved hassle-free, comfortable operability of FamiLock. Users often purchase entrance doors as they are proposed by our builders, but we have seen an increasing number of cases where entrance doors are chosen specifically because they include the Bluetooth equipped FamiLock.

What do you think are the requirements behind an effective digital key for smart home systems?

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Since front doors are installed in various regions and vary according to floor plan, the radio wave environment around entrances can vary significantly. As locking and unlocking entrances are performed daily, any delays in response or even a single authentication failure can cause issues for the user that can lead to a decrease in satisfaction.

From a safety perspective, vulnerabilities can be a risk to household security, so constant security maintenance is a necessity. As houses are typically in use for several decades, it is essential that building owners invest in technology that can endure into the future. Taking all this into consideration, we believe that the following conditions are necessary for digital key systems:

    • High reliability and secure communication
    • Stability and minimal latency
    • Flexibility to adapt to changes in the installation site

After evaluating these requirements and considering the potential for future developments, we determined that Bluetooth® technology, which meets these requirements and has promising future prospects, was the option that suited us better than any other.

What role do you think Bluetooth technology will play in the future of digital key technology as a whole?

Bluetooth® technology offers stability in communication, widespread usage with smartphones, and the ability to transmit more information than the LF/RF waves used in conventional smart entry keys. We believe Bluetooth technology can make a significant contribution to the IoTization of building materials, including entrance doors.

By utilizing applications, it becomes possible to add additional features that were previously unavailable, such as changing/checking the settings of smart entry keys and understanding the locking and unlocking history of users. By collecting information from entrance doors and connecting it directly to the cloud, we can anticipate the collection and utilization of big data. This opens up possibilities for future development and business expansion, allowing for the potential of upcoming advancements and new ventures.

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日本の住宅建材及び設備機器産業で最も知名度の高い会社の一つであるLIXILは、革新的な家庭用デジタルキー「FamiLock」の製品ラインにおいてBluetooth技術を選択しました。同社はこの製品の開発において、Bluetoothのスマートフォンへの広範な普及、エネルギー効率、堅牢なセキュリティを活用することにより、ユーザーがスマートフォンを使い、容易にドアを施錠・解錠できるようにしました。このデジタルキー技術の開発について(株)LIXIL LIXIL Housing Technology サッシドア事業部の酒井 秀忠 氏にお話を伺いました。





スマートフォンを玄関のキーにするに当たり、当時の選択肢はBluetooth以外にもNFC、Wifiが候補に挙がっていました。NFCの強みとしてはスマートフォンの充電が切れた後でも施解錠できることですが、通信距離の短さからドアの認証部に接するまでスマートフォンを取り出して近づける必要があり、帰宅時に手が塞がっているシーンでは利便性に欠けました。一方でWifiはNFCよりも広範囲での認証形成が可能ですが、高出力故にドア側の電池が持たないことから、玄関ドアのスマートエントリーキーの通信方式として採用することはできませんでした。その点、BluetoothはNFCよりも広範囲、Wifiよりも省電力(Bluetooth Low Energyを採用)であり、ユーザーにも広く知られていることや、技術的な実績も多く、今後も長く使用されることを想定しBluetoothが最適であると考え、採用致しました。





  • 通信における高い信頼性・セキュリティ維持体制
  • 通信の安定性・遅延が少ないこと
  • 設置環境変化における融通性





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