Untangling The Wires By Bluetooth Low Energy (BLE)


Devices and Machines are evolving into their smarter version with the requirement of
additional sensors, smarter display and ability to contact to the outside world. Along with
these features also comes the complexity. And if something goes wrong, the devices need to be opened up or are connected to ports to diagnose the problem. These issues add several limitations such as waterproofing, product cost and serviceability cost of the device. Many times, it not possible to add a dedicated display to the device because of cost or form factor reasons. In this article, we will discuss some of these issues in Smart devices and how BLE is increasingly used to tackle those issues.

Vishal Goyal

Bluetooth Low Energy [BLE]

Bluetooth Low Energy or BLE is a wireless personal area network technology and is widely
used in Smart devices. With the adoption of this technology by Bluetooth Special Interest
Group [SIG], it because part of Bluetooth technology and ecosystem. Today it is available in almost every Smartphone and its smart accessories such as wearable bands, watches,
fitness devices etc.

According to ABI Research, 2020, the single-mode BLE market is expected to achieve 3X
growth from 2020 to 2024 with the cumulative shipment of 7.5billion pcs. Single-mode BLE
devices are those that have only BLE and not in combination with classical Bluetooth. The
reason for this phenomenal growth is ultra-low current consumption, faster and secure
connection, low cost and smaller footprints.

BLE is not only used in smart gadgets and user interface devices but also increasingly used
for purposes which do not concern the end-user much. In many cases, BLE comes as a part
of the device purely for manufacturers.

In the article, we will primarily focus on use cases which are essential to manufacturers or
service providers.

Use cases

Easy customization

A LED driver power supply of particular power rating can be used to drive LEDs in various
configurations. The LED parameters may also be different. Making a dedicated power supply for each type of LED or configuration is very inefficient. Similarly, sensor nodes may need different configuration when installed indoor, outdoor or other locations. Many times, menu options or Interface in machines or devices available to users may also need customization.

If manufacturers add BLE interface to these devices, they can mass-produce the products
and enable customization at the deployment stage. They will also avoid the need to wired
interfaces which would otherwise be costly and limited other features and aesthetics of the
devices or machines.

Service and maintenance

Another primary concern of manufacturers is to provide the service and maintenance of the
products effectively and economically. In the traditional method, when a product breaks
down or it needs assistance, the user brings the product to the service centre or the service
professional visits customers premises. And in most of the cases, the product needs to be
opened to diagnose or identify the issue. In some products, the wired Interface is available,
but it again complicated way and works in association with complex diagnostic machines.
If the product comes with inbuilt BLE connection, the service engineer can enter into the
device wireless using specific App on a mobile phone or specific diagnostic device. There is
also a possibility of supporting the user remotely who will connect the device using App and
let the remote connection to service engineers.

BLE can also enable predictive maintenance features to the simplest of devices. The
devices can send machine parameters and sensor input to BLE connected Smartphone App.
The App in-turn can upload the data to the cloud where the data can be analyzed to identify the problem before breakdown.

Firmware upgrade

Another critical requirement in smart devices and machines is the capability to upgrade the
firm after is shipped to the customer. The need to upgrade the firm can come from several
reasons. Some of the reasons to upgrade the firmware are listed below

  • Bug Fixes in the released code
  • Enhancements in the existing products
  • Corruption of existing code
  • Change in user’s settings

The firmware upgrade is also a significant component of service and maintenance as
discussed in the previous section. BLE is also mainly very used as a complementary
technology to LPWAN such as Sigfox and LoRa. As these technologies are optimized for
long-range low data rate, presence of BLE make them more useful from firmware upgrade
and serviceability point of view.

BLE can make a firmware upgrade as seamless as possible. BLE can transparent act as a
bridge between mobile phone and central controller or processor and allows the code image
to be transferred from Smartphone to the empty memory of the processor or dedicated
memory. The new code image can be pushed to a Smartphone App directly from the cloud.
In some cases, dedicated gateway devices other than Smartphones can also be used for
firmware upgrade.

Remote Reading

In many devices, the manufacturer is interested in getting the usage reading of the device
and bill the customer accordingly. Nowadays, many devices are available to customers on
pay per usage basis rather than on the upfront payment basis. This is also called as TaaS or

Things as a Service. Some of the typical devices are Energy meters, Solar Inverters, water
purifiers etc.

Energy meters are a typical example where reading using the optical port is a very
complicated and slow process. Many time meters are not easily accessible to the person
who wants to take its reading.

Presence of BLE in such utility meters and appliances make it very easy to service
engineers to collect the meter readings. Service providers can also enable consumers to
collect reading using their App and push to the cloud.

Simplified HMI

As we have seen in several examples above BLE has enabled human-machine Interface
very easy. On top of the uses cases we discussed, a BLE connected devices may be made
available to the user without a dedicated display, and the mobile phone screen becomes the
screen. In some Industrial devices, other integrated displays or tablets can also be used.
Decoupling of a display from the main machine has several advantages. It not only saves
the cost and real estate of the device but it also allows to upgrade the Interface without
upgrading the whole device. An upgrade of mobile phone App is enough to change the user
experience or service experience.

BlueNRG’s design flexibility

Bluetooth Low Energy devices can be integrated into smart devices and machines in three
ways

  • Network processor
  • Data Pump
  • Application processor

The details of each of the modes are listed below:

In Network processor mode, the Bluetooth application runs inside the main microcontroller
or microprocessor of the system, whereas radio stack resides inside a Bluetooth network
processor IC acts, which understands the HCI/ACI commands coming from microcontroller

or processor. The HCI/ACI commands are standard commands defined by either Bluetooth
SIG or manufacturer to interface with Bluetooth Host or controller.

In this mode, no programming is required in Bluetooth network processor IC, and all the
Application resides in the main controller or processor.

In Data pump mode, the Bluetooth processor acts as a transparent Interface between
central controller or processor with the external world. The main controller or processor
pushes the data on the serial bus, such as UART or SPI. The information is interpreted by
Application code inside Bluetooth processor for further processing and communication.
In this mode, no Bluetooth specific programming skill is required in the main controller or
processor: only the Bluetooth processor need to be programmed, while keeping the
UART/SPI communication on both ends.

In Application processor mode, the only single-chip architecture, the Bluetooth processor
acts as the main controller of the system. It not only manages Bluetooth communication but other peripherals such as sensors, LEDs, push- buttons, memories etc. It is mainly used in simpler devices and gadgets.

The BlueNRG Family devices from STMicroelectronics supports all the three modes in the
single device so offer customer flexibility to choose any method during its design cycle. It is
even possible to switch between network processor and Data pump options by Firmware
upgrade even after the device is shipped.

Another BlueNRG’s big plus in terms of design flexibility is the module’s offer. BlueNRG
modules are equipped with an on-board antenna, crystal and RF balun, offering this way a
reliable solution that ensures a quick time-to-market. They are a certified Bluetooth
Qualification Expert (BQE) solution that is also fully RED, IC and FCC approved at least,
thus ensuring rapid integration into the final application.

Why is Bluetooth Low Energy so popular?

As discussed previously in the article, ABI research (2020), expects 7.5 billion single-mode
Bluetooth LE devices cumulative shipment from 2020 to 2024. Bluetooth is very popular
because of several ecosystem and technical reasons

  • Standard connectivity among portable devices
  • Sleep current consumption less than 1uA to make it suitable for even battery-powered devices
  • Bluetooth 5.0 supports three different PHY to choose best-optimized tradeoff
    between range and data rate
  • Capability to get connected in a Mesh network
  • Advanced encryption engines and pairing mechanism etc.

STMicroelectronics has launched 3rd generation Bluetooth Low Energy device, named
BlueNRG-LP, which not only support features listed above but is also the world’s first device
designed to support 128 concurrent connections. It also helps image authenticated

technology to enhance cybersecurity by always checking the stack before starting to allow
only signed firmware images to run.

We discussed in the article that BLE is not only emerging as the technology of choice for
connecting accessories to Smartphone but also enhances serviceability, diagnostic
capability, firmware capability and aesthetics of the device. It also leads to the emergence of new business modes, such as TaaS. Continuous innovation makes BLE as the technology
of choice, and STMicroelectronics continues to bring most advance innovations that matter
the most to customers.


 





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