I²C smartBLE Smart Device
This project is shared with the fischertechnik Corner website, as the first smart sensor is intended for the fischertechnik Robo TX controller.
This part in more technical oriented.
The smartBLE smart device is very similar to the smartWiFi, except it relies on Bluetooth Low Energy instead of WiFi for a lower power consumption.
Selecting BLE and MCU
One major criteria is power consumption. BLE or Bluetooth Low Energy allows low power consumption.
The LaunchPad CC2650 was discarted: the BLE stack is not available on Energia due to resticted licensing.
The compact form-factor, the powerful Cortex M0 and the very popular nRF51822 make the Adafruit Feather M0 Bluefruit a perfect match.
Selecting the Framework and IoT Service
Already selected for the WiFi variant, Blynk brings the convenience of an app for Android or iOS smartphone to design and display the end-user interface.
Blynk now supports BLE. Connection is direct, with no need for a in-between server.
Building the Prototype
There was one single step for the prototype.
The Adafruit Feather M0 Bluefruit is self-contained, with a 3.3V voltage regulator. The only external part is a logic level converter, on an external breadboard for the prototype.
As always, I used the standard tools for development, including embedXcode for programming and a Segger J-Link for debugging.
Total consumption barely reaches 20 mA, making it perfect to be powered by the RoboTX.