Nordic Bluetooth LE and cellular IoT smart plug provides remote energy management of appliances

China-based MOKO Smart has developed a smart plug for energy management applications in the smart home and energy metering sectors to support both consumers and energy-solution providers.

The ‘MK117NB Smart Plug’ can be used to monitor energy usage and save power consumption by remotely controlling load switches. It features a power and energy meter and has a measurement accuracy of ±0.5 percent. Users can track hourly, daily, monthly, and historical total energy consumption through a smartphone app.

IoT-enabled electrical devices

MK117NB Smart Plug supports a range of plug types and can be used in many countries. It allows ordinary electrical devices to become IoT enabled, providing users with the ability to better understand their energy usage and convert real-time electricity consumption into accurate billing data. For example, the device can easily manage all electrical equipment such that it turns off during non-working hours, and then automatically turns on during working hours, reducing unnecessary power consumption and manual labor.

We selected Nordic’s nRF9160 because it supports complex application software, while the SiP’s support for global networks facilitates the development of MOKO Smart devices

Jerry Li, MOKO Smart

The device’s multiple protection mechanism supports overload, overcurrent, overvoltage and undervoltage protection. When the plug detects the measured value is out of the safe range, and the duration exceeds the safe time, it will automatically switch off to reduce the risk of damage to the connected electrical device. The RGB LED ring also changes color according to the power used by the plugged load, providing a convenient way for users to capture the change of load power quickly and intuitively.

MK117NB Smart Plug integrates the Nordic nRF52833 SoC as the device’s main processor for running sensor-based algorithms to monitor energy consumption and measure parameters including instant voltage, current, active power, power factor, and frequency with high accuracy. The SoC incorporates a 64 MHz Arm® Cortex-M4 with floating point unit (FPU) microprocessor.

NB-IoT wireless connectivity

The smart plug also includes Nordic’s nRF9160 SiP with integrated LTE-M/NB-IoT modem and GNSS to provide NB-IoT wireless connectivity for low power consumption wireless data communication over a cellular IoT network. The smart plug can connect to third-party customer Cloud servers and a smartphone/tablet app via different MQTT servers such as EMQTT and Mosquito.

In addition, MK117NB Smart Plug can be deployed as a Bluetooth® LE gateway for personnel positioning and asset management applications. In a smart office, the gateway only needs to scan an employee's ID card (beacon) and upload the data to the server to easily realize intelligent attendance and employee interaction.

“We selected Nordic’s nRF52833 for our MK117NB Smart Plug because of features like the SoC’s powerful performance, generous Flash and RAM memory, and rich peripherals and IO ports, which combine to meet the requirements of different applications,” says Jerry Li, R&D Director at MOKO Smart. “We selected Nordic’s nRF9160 because it supports complex application software, while the SiP’s support for global networks facilitates the development of MOKO Smart devices.

“From the pre-research of the product based on the development board, to the later prototype test, Nordic has provided us with a lot of help, including chip introduction, SDK [Software Development Kit] technical support, layout precautions, and rapid progress after applying for samples.”