First steps with Bluetooth Low Energy

Bluetooth Low Energy (LE), also known as Bluetooth 4 and formerly known as Bluetooth Smart, is supported by most mobile and desktop operating system and can be found in many wireless devices. It was developed by Nokia in the early 2000s and first marketed as Wibree, a competitor to the Zigbee low-power wireless standard.

While Zigbee is used in many smart home devices, like smart meters and light bulbs, the rebranding of Wibree as Bluetooth LE helped it to take over the smart phone market, with around 90% of new mobile devices now supporting Bluetooth LE.

Bluetooth LE has open specifications (called profiles) for various types of devices, including blood glucose meters (BGMs) and continuous glucose monitors (CGMs). At Tidepool we've had to work very hard to get communication specifications from device manufacturers in order to communicate with their devices over USB. These are all proprietary protocols which have to be developed for and supported separately, and apart from Ascensia (previously Bayer), not a single company have published their protocols in the open. Now with Bluetooth LE, having a common standard specifying how these devices should communicate that is supported by device manufacturers is great!

I downloaded an app from the App Store called nRF Toolbox by one of the Bluetooth LE chip manufacturers, Nordic Semiconductor. It has support for various BLE profiles, including the BGM and CGM profiles. I was able to successfully connect to and read data from a Bluetooth LE-enabled BGM called the True Metrix Air, after entering the device serial number to pair: