Super Low Power Wi-Fi and Bluetooth LE Unlock Smart Locks

In this article, we look at how Super Low power Wi-Fi and Bluetooth LE enable smart locks to be more agile and reliable by demonstrating these features with a case study from Renesas.

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24 Aug, 2022

What are smart locks?

Smart locks are electrically powered locks that can be operated wirelessly. Smart locks can be unlocked using a code, an app, your fingerprint, a fob, a home assistant, or a combination of these methods. If you have recently checked into a hotel, you will have used a smart lock when swiping your hotel door open. 

Smart locks are generally battery-powered and provide a means of communicating with their user wirelessly. This is usually done using Bluetooth/Wi-Fi or both. For smart locks to fulfil their potential as convenient and secure, they must be able to perform consistently, quickly, and reliably. Central to this is accurate communication and long battery life. 

As features of smart locks increase, power usage also increases, endangering the convenience of these features. As smart lock applications proliferate (think shared micro-mobility) the need for low-power smart locks is essential. 

Smart Lock with Super-Low Power Wi-Fi and Bluetooth Low Energy: A case study 

Renesas, a semiconductor manufacturer headquartered in Tokyo, Japan has developed a smart lock reference design with Super-Low Power Wi-Fi and Bluetooth Low Energy for smart homes and smart buildings. The lock was designed to address the pressing demand for low-power connectivity in smart locks with additional ‘always on’ features such as fingerprint recognition. The smart lock reference design features fingerprint control, low-power Bluetooth, and low-power Wi-Fi options.

Image 1: Renesas smart lock schematic design. Source: Renesas Electronics Corporation [1]

A 6V battery powers the unit which consists of a fingerprint sensor, a Bluetooth Low Energy (BLE) interface, a Wi-Fi interface and various other sensors. Notice that the BLE, Wi-FI and BLE + Wi-Fi options provide cross-connections enabling the system to provide features such as a Wi-FI through BLE. 

Ultra-low-power Wi-Fi SoC 

A system-on-chip (SoC) is an integrated circuit that integrates all or most components of a computer or other electronic system. This solution uses the state-of-the-art SoC DA16200[2] which delivers year-plus battery life for always-connected Wi-Fi IoT devices. 

The DA16200 SoC brought a significant drop in terms of power usage without any trade-off in the range of output power. With the IoTMark®-Wi-Fi benchmark, the DA16200 set a score of 815 (equivalent to about 815 days of battery life for an IoT sensor running on two AA batteries).[3] This chip achieves ultra-low power consumption thanks to VirtualZero™ technology with virtually no power consumption in sleep mode while not actively transmitting or receiving data and extending the battery life as long as a year or more depending on the application. 

The chip is also said to implement “advanced algorithms” enabling it to stay asleep until the exact moment when it is required to wake up to transmit or receive.[4] The chip also features very strong IoT security, including WPA3 and TLS for authentication and encryption at the Wi-Fi and higher stack layers. 

Thus, the smart lock can utilize high-performing Wi-Fi features while consuming ultra-low power using this SoC. 

Low power Bluetooth 5.1 system-on-chip

The Renesas smart lock ensign also features the low-power Bluetooth 5.1 SoC, DA14531[5]. The DA14531 SmartBond TINY™ Bluetooth LE module provides among the physically smallest and lowest power Bluetooth 5.1, for battery-powered Internet of Things (IoT) devices. This SoC works with even the smallest capacity batteries (<30mAh). In addition to using low power and having a small size, this SoC is durable with multiple years of shelf life. This chip also has pins that enable the users to plug and play Bluetooth features to their IoT device. 

Ultra-Low Power Wi-Fi + Bluetooth® Low Energy Combo Modules

One of the key features of the Renesas smart lock design is that it has Wi-Fi/Bluetooth coexistence and can provision Wi-Fi through the Bluetooth LE connection. This single integration system is achieved by using the DA16600[6] Combo integrated circuits. Using this module, the system can be programmed to use the two channels (Wi-Fi and Bluetooth) and use the fastest mode of communication based on the internal algorithms and custom priority settings. This results in reduced power usage with provision for backup connectivity. 

Microcontroller to easily integrate a fingerprint module

The Renesas Smart Lock with Super-Low Power Wi-Fi and Bluetooth Low Energy comes with a high-performance 120MHz low pin count Micro Controller Unit (MCU) for adding a fingerprint module. Fingerprint authentication enables the user to use their biometrics for entry. This is a seamless and intuitive method of access that reduces the need for memorising codes and combinations. 

The Renesas lock also has the option of features such as a wide input range ultra-low quiescent current LDO that provides continuous low power regulation and Time of Flight (ToF) sensors for detecting motion. ToF can detect motion and respond in real-time while consuming low power, thus making the door locking and unlocking a seamless experience. 

The full technical details of the solution are available on the official website of Renesas Electronics Corporation[7]. You can also check out their RA2L1[8] and RA2E1[9], general-purpose Microcontrollers that use ultra-low power.

The world of keyless entry

Low power Bluetooth and WiFi are enabling smart locks - digital, keyless points of entry - to be more user intuitive, more reliable, and pack in more features. Smart locks are part of the growing IoT using advanced MPUs to deliver always-on features while using minimal power. To learn more about the Renesas smart lock, visit their website. 

About the sponsor: Renesas

At Renesas we continuously strive to drive innovation with a comprehensive portfolio of microcontrollers, analog and power devices. Our mission is to develop a safer, healthier, greener, and smarter world by providing intelligence to our four focus growth segments: Automotive, Industrial, Infrastructure, and IoT that are all vital to our daily lives, meaning our products and solutions are embedded everywhere.


References:

1. Renesas Electronics Corporation [Internet]. Renesas.com. Available from: https://www.renesas.com/eu/en?utm_campaign=conn&utm_source=wevolver&utm_medium=article&utm_content=lp

2. DA16600MOD - Ultra-Low Power Wi-Fi + Bluetooth® Low Energy Combo Modules for Battery-Powered IoT Devices | Renesas [Internet]. Renesas.com. Available from: 

https://www.renesas.com/products/interface-connectivity/wireless-communications/wi-fi/da16600mod-ultra-low-power-wi-fi-bluetooth-low-energy-combo-modules-battery-powered-iot-devices#design_development?utm_campaign=conn&utm_source=wevolver&utm_medium=article&utm_content=pp

3. Investegate |Dialog Semiconductor Plc. Announcements | Dialog Semiconductor Plc.: Dialog Semiconductor Achieves Industry's Highest Ranking for IoTMark(TM)-Wi-Fi Benchmark [Internet]. Investegate.co.uk. Available from: https://www.investegate.co.uk/dialog-semiconductor-plc./eqs/dialog-semiconductor-achieves-industry-s-highest-ranking-for-iotmark-tm--wi-fi-benchmark/20210621070002EJWTH/

4. (CNXSoft) J. Dialog DA16200 WiFi SoC Promises a Year of Battery Life for Always-Connected IoT Devices - CNX Software [Internet]. CNX Software - Embedded Systems News. Available from: https://www.cnx-software.com/2020/05/27/dialog-da16200-wifi-soc-year-of-battery-life-for-always-connected-iot-devices/

5. DA14531 - SmartBond™ Ultra-Low Power Bluetooth® 5.1 System-on-Chip | Renesas [Internet]. Renesas.com. Available from: https://www.renesas.com/products/interface-connectivity/wireless-communications/bluetooth-low-energy/da14531-smartbond-ultra-low-power-bluetooth-51-system-chip?utm_campaign=conn&utm_source=wevolver&utm_medium=article&utm_content=pp

6. DA16600MOD - Ultra-Low Power Wi-Fi + Bluetooth® Low Energy Combo Modules for Battery-Powered IoT Devices | Renesas [Internet]. Renesas.com. Available from: https://www.renesas.com/products/interface-connectivity/wireless-communications/wi-fi/da16600mod-ultra-low-power-wi-fi-bluetooth-low-energy-combo-modules-battery-powered-iot-devices#design_development?utm_campaign=conn&utm_source=wevolver&utm_medium=article&utm_content=pp

7. Smart Lock with Super-Low Power Wi-Fi and Bluetooth Low Energy | Renesas [Internet]. Renesas.com. Available from: https://www.renesas.com/application/home-building/smart-lock-super-low-power-wi-fi-and-bluetooth-low-energy#overview?utm_campaign=conn&utm_source=wevolver&utm_medium=article&utm_content=wc

8. RA2L1 - 48MHz Arm® Cortex®-M23 Ultra-Low power General Purpose Microcontroller | Renesas [Internet]. Renesas.com. Available from: https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ra2l1-48mhz-arm-cortex-m23-ultra-low-power-general-purpose-microcontroller?utm_campaign=mcu_ra2l1&utm_source=wevolver&utm_medium=article&utm_content=pp

9. RA2E1 - 48MHz Arm® Cortex®-M23 Entry Level General-Purpose Microcontroller | Renesas [Internet]. Renesas.com. 2022. Available from: https://www.renesas.com/products/microcontrollers-microprocessors/ra-cortex-m-mcus/ra2e1-48mhz-arm-cortex-m23-entry-level-general-purpose-microcontroller?utm_campaign=mcu_ra2e1&utm_source=wevolver&utm_medium=article&utm_content=pp

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24 Aug, 2022

Data Scientist & Writer - Conquering challenges with passion and creativity. Currently pursuing MSc in Artificial Intelligence & Machine Learning at the University of Birmingham, United Kingdom.

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