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14 Oct Key#® and Bluetooth Low Energy (BLE)

Posted at 13:52h in featured, Product Design, Software, Wearable by

Since its release, Key#®, Key Tech’s configurable software tool, has provided customers a variety of advantages when developing device prototypes and running assays. This proprietary tool benefits our clients by accelerating prototype development and testing.  Although we’ve covered several benefits and applications of the Key#® framework in previous posts, one area the software has yet to be used is communication with devices over Bluetooth Low Energy (BLE). Configurability is one of the key advantages to Key#®, and expanding the software to interface with a ubiquitous technology like BLE can be invaluable for teams looking to add wireless connectivity to their products.

Missing Link Behind the Technology

Similar to its sister technology, Bluetooth Classic, BLE is a wireless technology that divides data into packets and transmits them over a series of RF channels. Apart from their shared name, however, the two technologies are largely incompatible, requiring different chipsets to support one or both.

BLE typically finds applications in low-power mobile and wearable devices like those that Key Tech designs, making it the preferred choice for wireless connectivity in many devices. These devices may be too small or constrained to support a wired debug interface, so BLE could ideally also be leveraged as a communication interface between the devices and Key#® during development. The issue? Key#® traditionally expects a serial communication protocol, and BLE does not natively support serial links. This is because the technology lends itself to small, infrequent messages, as opposed to a continuous stream of information, such as might be found in Bluetooth Classic.

Bridging the Connection between BLE & Key#®

While there are services and off-the-shelf (OTS) devices to help convert from Bluetooth Classic to serial, neither these devices nor the Bluetooth module on your computer support serial services for BLE. This poses a problem with a couple of possible solutions.

  1. Modify Key#® to communicate with the built-in Bluetooth chipset in your PC and build a software serial-to-BLE bridge.
  2. Modify an OTS BLE dongle device to act as a plug-in hardware serial-to-BLE bridge.

The first method, while feasible, presents some additional considerations such as hardware compatibility. Due to its convenience and accessibility, the Key Tech team moved forward with testing a BLE dongle device to integrate BLE within a Key#® environment. The BLE dongle, loaded with custom code, plugs into your PC and appears as a virtual COM port to Key#®. The dongle also connects wirelessly to your BLE-enabled device and serves as a pass-through serial-over-BLE bridge using the Nordic UART Service, allowing for end-to-end communication between the device and Key#®!

Looking Ahead for Customers

Moving forward, Key Tech aims to improve the BLE-Key#® connection in a variety of ways:

  1. Multiple Devices: Being able to select from multiple devices would provide greater flexibility in applications with several devices running simultaneously.
  2. Connection Stability: Reducing loss of packet data and minimizing disconnects between the device and Key#® would improve consistency in performance amongst BLE-Key#® connections. At the same time, we must ensure our data throughput is still sufficient with any added application-layer robustness features.
  3. BLE Platform: Key Tech aims to establish a BLE reusable platform that can be built upon to leverage existing libraries and tools compatible with Key#™. Developing this platform and a base code library would enable customers to take advantage of BLE technology and Key#® as quickly as possible.
  4. Integrating with BLE Services: Serial communication is great for testing, but it may not be ideal for your final commercial device, such as when integrating with a mobile app. Key#®’s modularity allows it to be modified to support any communication protocol, including BLE’s Generic Attribute Profiles (GATT).

If you are developing a platform using BLE we would love to talk. Reach us at TalkToUs@keytechinc.com.

Kun Li
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