Building a smart band

I’m doing a project of a smart band with accelerometer and heart rate sensor with the goal of detecting heart attack, I’m planning to connect it to IBM Watson IOT platform which requires the device to be able to communicate using http or mqtt protocol, I also would like to connect it to a mobile application which display the analyzed data from IOT platform which is connected to the Data Science Experience where I’m planning to use machine learning to analyze the datas, and also show notifications when there are anomalies. I don’t want the bulky Arduino board, ethernet shield and all the cables to be attached to the device and would like the device to look like something like the image on the attachment, how can I obtain that? any feedback on how to do this project would be appreciated

Bluetooth LE linked to a smartphone is one way to go. Adafruit and SparkFun NRF52 boards are available for use with the Arduino IDE. Older NRF51 boards will probably works as well.

Arduino sells an NRF52 board but it is the size of an Uno.