Forget the buttons and the display, just add Bluetooth – Embedded Computing Design

Forget buttons and displays, just add Bluetooth

05 June 2023


Forget buttons and displays, just add Bluetooth

Smartphones have become ubiquitous, in everyone’s pockets, purse and backpack, replacing many other household items. We rely on them for everything from emails, to banking, to opening our front door, and even the occasional phone call. However, a quick look at our homes and businesses will quickly reveal two things smartphones have yet to replace: buttons and a seven-segment display.

Buried deep within menus and button presses, many devices offer an incredible amount of information and customization possibilities that require cumbersome programming. With Bluetooth Low Energy (LE) found in virtually every smartphone on the planet, it’s time to break free from buttons and displays.

For example, imagine you could program a pressure cooker by simply selecting the recipe on a smartphone instead of manually pressing buttons and squinting at the display. Using Bluetooth LE with a smartphone app, designers can catapult their products into a premium user experience, improving customer satisfaction and product reviews.

Today’s Bluetooth microcontrollers and the Bluetooth standard have made great strides in reducing cost, complexity, and power consumption. First, Bluetooth evolved through the Bluetooth LE standard, which brings many improvements over classic Bluetooth. Bluetooth LE dramatically reduces power consumption through numerous optimizations, primarily by sending short bursts of data and then going into sleep mode. This is exactly how data typically flows for a user interface: small amounts of data are sent at regular intervals.

Bluetooth LE also simplifies the pairing process by making it much easier and more reliable for end users to connect their smartphones to the end device. Finally, Bluetooth LE is designed around profiles, which structure the services and data exchange between the smartphone and the device, allowing software designers to focus on their application, not the Bluetooth connection.

A quick internet search reveals many resources explaining the ins and outs of how Bluetooth LE works. Basically, Bluetooth LE is built around one central device and the other the peripheral one. The control panel scans for available peripherals, which advertise on specific channels. Once the central and peripheral devices establish a connection, the peripheral becomes the server, providing the central, now the client, with information about its available services and data.

Establishing this connection is handled by the GAP (Generic Access Profile) portion of the protocol, while the Generic Attribute Profile (GATT) handles the data exchanged between the two devices. The Bluetooth LE standard contains a multitude of predefined profiles for many common use cases and opens the door to custom profiles. For a user interface, one of the best places to start learning about Bluetooth LE is with a simple wireless UART.

Most designers are familiar with using the Universal Asynchronous Receiver-Transmitter (UART) protocol for diagnostic and debugging purposes. Sending data, status, and configuration information to a smartphone app via UART is relatively similar.

As shown in Figure 1, most Bluetooth microcontroller vendors, including NXP® Semiconductors, provide a wireless UART in their SDK that mimics a wired UART connection. With an established wireless data path, data flows between the Bluetooth device and the smartphone allowing the designer to perform all display and button functions by passing data between the end device and the smartphone. The end user can now quickly and easily see information and access configuration options that were previously buried behind confusing menus and button presses.

(Figure 1 – Data sent to a PC via Bluetooth using NXP’s wireless UART sample program and IoT Toolbox app)

With a basic understanding of how Bluetooth connections work and an easy way to wirelessly exchange data, the next step is to examine the hardware architecture of the end device. Many high-end devices require high-performance application processors (MPUs), such as NXP’s i.MX series, while others may only need a single MCU.

Based on the needs of the end device, there are three typical Bluetooth connectivity configurations that scale from standalone to hosted with network coprocessor (NCP) and hosted with radio coprocessor (RCP), see Figure 2.

(Figure 2 – Options for adding Bluetooth connectivity to a system)

In a standalone configuration, there is only one processor in the system running both the Bluetooth protocol and the application. If more capabilities are needed, a host processor, such as an NXP i.MX RT crossover MCU, can be added that runs the application, while the wireless MCU acts as a network coprocessor and runs the entire Bluetooth protocol.

For systems using a high-performance application processor, the Bluetooth protocol can be split cleanly between the link layer and the stack, with the Bluetooth MCU running only the link layer. This split and the required Bluetooth stack is standard in most Linux distributions, making it easier to implement. Many processor vendors, including NXP, offer software and products for all three configurations, opening up Bluetooth connectivity to a wide range of end device types.

With a smartphone in every pocket, adding Bluetooth connectivity to a self-contained terminal device opens the door to a rich graphical user interface via a smartphone app. No more special devices, modern Bluetooth MCUs are more capable and easier to use than ever before. NXP’s latest K32W148 Bluetooth MCU, for example, offers 96MHz of performance, over 1MB of flash, and advanced security features, all while minimizing power consumption.

Bluetooth MCUs like this offer the ability to add wireless and upgrade the entire end device with increased speed, capacity, and security. End device designers can easily upgrade their products by replacing the buttons and venerable seven-segment display with Bluetooth and a smartphone app. This, in turn, leads to happier users, better online reviews, and ultimately more sales.

#Forget #buttons #display #add #Bluetooth #Embedded #Computing #Design

Previous articleApple renews watchOS 10 with widgets, topo maps, awareness features and more
Next articleAndroid apps with 30 million downloads contain Android SpinOk malware – delete them now


Please enter your comment!
Please enter your name here