Nordic-powered wireless indoor alert system provides round-the-clock assistance to service users

by SGWireless
Thursday, November 10, 2022

[Chinese below]

Oslo, Norway, 19 April, 2022 – Hong Kong-based IoT technology solutions company, SG Wireless, has partnered with the local non-profit charitable organization Senior Citizen Home Safety Association (SCHSA), to develop the ‘Wireless Personal Emergency Link’ (WPEL). WPEL is an indoor Bluetooth® LE/LTE Cat 1 emergency alert system. Installed in the homes of service users, the system is designed to support senior citizens who live alone and individuals who are unable to care for themselves and whose caregivers may not always be available. 

Always-on connection

A revamp of the SCHSA’s wired landline solution, the WPEL provides service users with a guaranteed, always-on connection to the ‘Care-on-Call Service Call Centre’. This service call center is operated around-the-clock by the SCHSA, Hong Kong’s largest emergency assistance service provider that supports and delivers integrated care to over 400,000 accumulated senior citizens. The new wireless solution eliminates the need and cost for a fixed landline and makes it a viable option for a broader range of service users. 

The WPEL comprises three hardware elements: The ‘Panic Button’, which integrates the Nordic Bluetooth 5.3/Bluetooth LE nRF52840 SoC, and the ‘Main Unit’ and ‘Range Extender’, which integrate the nRF52840 SoC-based proprietary, pre-certified SGW1111 and SGW1110 modules respectively. All three devices use the nRF52840 SoC’s Long Range technology to improve radio sensitivity and, in turn, range.

The Panic Button is designed to be wearable for portability around the home. It has an easy-to-click SOS button that instantly connects service users to the service call center following a one-button trigger to the Main Unit. The device provides Bluetooth 5 Long Range connectivity at up to 200 meters line-of-sight, which is ample coverage for the average Hong Kong apartment. The Panic Button is also IP65, IP66, and IP68 dust- and waterproof-rated and can be used indoors in bathrooms and kitchens.  

The Main Unit is a cellular gateway performing as a network access point that works with the multiple communication protocols of Hong Kong’s four network providers (CSL, SmarTone, China Mobile, and 3HK). Once installed, it enables calls over the network to the service call center when manually triggered by buttons or receiving Bluetooth LE signals from the Panic Button. The Main Unit supports up to eight Bluetooth LE connections with either the Panic Button or Range Extender at one-second response times.

The Range Extender is a plug-and-go device designed to extend Bluetooth LE distance to flexibly address various problems that disrupt connectivity in enclosed indoor areas, such as blind spots. The device eliminates the possibility of lost or missed signals from the Panic Button wherever and whenever it is triggered by service users in their homes. 

Directing data

The nRF52840 SoC acts as the system host on the Main Unit, enabling wireless communication with the Panic Button and Range Extender, as well as directing data to the backend server for processing. In addition, the SoC’s +8 dBm TX power provides extended coverage for the emergency alert system.

A web-based processing platform designed to handle voice message transmissions is used at the service call center. The platform is pre-programmed to work with each set of Panic Button, Main Unit, and Range Extender so that a unique connection to the service call center for each service user is immediately enabled when the service user plugs in the Main Unit to power. 

Under normal operation, the Main Unit is powered by 5V DC 2000 mA through a USB-C interface. In the event of a power outage, when help may be most needed, the Main Unit can also run on backup lithium batteries and the nRF52840’s low power feature significantly reduces power consumption. The Panic Button runs on a CR2450 lithium coin cell battery that provides up to three years of battery life before replacement is required. The Range Extender works directly with local power outlets and can be immediately deployed when connected to power.

“Nordic’s nRF52840 is arguably the most well-rounded and cost-effective SoC in the Bluetooth LE class for its size,’ says Ken Wong, CTO at SG Wireless. “The SoC’s 64 MHz M4 processor eliminates the need for additional processing chips, which has enabled us to develop the smallest Bluetooth LE module known in the market (10.2 by 14.1 by 1.9 mm with 72 pins). Subsequently, integrating the module ensures Bluetooth LE products are compact yet powerful, featuring Bluetooth 5 Long Range connectivity as well as high radio sensitivity.

“In addition, reference codes from Nordic’s comprehensive SDK [Software Development Kit] have undoubtedly shortened the product development cycle and enabled SG Wireless to do the same for its users,” says Wong.


SG Wireless使用Nordic nRF52840作為一線通®無線平安鐘的緊急求助按鈕之低功耗藍牙連接

香港物聯網技術解決方案企業SG Wireless 與當地非牟利慈善團體「長者安居協會」合作開發全新「一線通®無線平安鐘」室內緊急警報系統,產品採用低功耗藍牙(Bluetooth® LE)和LTE Cat 1通訊技術,適合於獨居長者、自理能力低和未必時常有照顧者陪伴的人士家中安裝。


線通®無線平安鐘由三個設備組成:採用Nordic nRF52840藍牙5.3/低功耗藍牙系統單晶片(SoC)的「遙控求助掣」,以及「無線平安鐘主機」和「藍牙範圍擴展器」;後兩者分別採用基於nRF52840 SoC的預先認證的SGW1111和SGW1110藍牙模塊開發而成。這三個設備都使用了nRF52840 SoC的遠距離技術以提高無線電射程的靈敏度,旨在擴展藍牙距離。


主機是個蜂窩網關以用作網路接入點,可與香港四家主要網絡供應商 (CSL、SmarTone、中國移動和3HK) 的多種通訊協議配合使用。一旦安裝完畢,當其按鈕被觸發或接收到遙控求助掣的低功耗藍牙訊號時,便會通過網路連接到服務熱線中心。主機可通過低功耗藍牙連接多達8個遙控求助掣或藍牙範圍擴展器, 於1秒鐘內作出回應。


nRF52840 SoC為主機核心,支援與遙控求助掣和藍牙範圍擴展器的無線通訊,以及將數據導向到後端伺服器進行處理。此外,主機以SoC的 +8 dBm發送功率和 125 kbps 數據速率運行,可把覆蓋範圍大大提升。


在一般操作情況,主機通過USB-C接口由5V DC 2000 mA供電。如果發生停電時,主機可使用其備用鋰電池運行,因nRF52840的低功耗特性十分省電,使續航力大增。遙控求助掣使用CR2450鈕扣電池運行,可達到三年的電池使用壽命。藍牙範圍擴展器可直接與本地電源插座配合使用,接通電源後可立刻使用。

SG Wireless首席技術官王永德博士表示︰「在同樣尺寸的低功耗藍牙解決方案中,Nordic的nRF52840幾乎可以說是最完善和最具成本效益的SoC。這款SoC內置64 MHz M4處理器,因此不需要額外的處理晶片,使我們能夠開發出市場上最小尺寸的低功耗藍牙模塊(10.2 x 14.1 x 1.9 mm,72 針)。這個模塊確保低功耗藍牙產品不僅兼具細小體積和強大功能,並且擁有藍牙5遠距離連接性能和高無線電射程的靈敏度。」

王永德博士說道︰「此外,完整的Nordic軟件開發套件(SDK)提供了參考程式碼,無疑縮短了產品開發週期,也使SG Wireless能夠更快為使用者設計產品。」

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