Hi,

I am a (French, sorry for my English) software engineer with very little knowledge in hardware. As part of a prototype, I'd like to replicate the functionalities of " Mi Band" wristband.

First , I would like to control the lighting of a LED and retrieve the motion sensor data through bluetooth .

Secondly , I would like to control a capacity touch sensor and vibrator sensor.

Now, I need your help to choose the Hardware !

Based on my research, the NRF51-DK board seems ideal. It is "mbed enabled" based on the Low-Power Cortex M0 chip, already has a LED and a button

What about the others sensors. I have take a look at https://developer.mbed.org/components/cat/sensors/ but i'm lost. Ideally , I'd like to find examples to speed up my prototyping and sensors that are plug and play (ideally of course :D) with the board.

Motion sensor:

- ADXL362 (3-axis) -> https://developer.mbed.org/components/ADXL362-3-Axis-Digital-Accelerometer-8g/

- MPU-9150 (9 -axis) -> https://developer.mbed.org/components/MPU-9150/, project based on http://www.twiz.io/

- BNO055 (9-axis) -> https://developer.mbed.org/components/Bosch-Sensortech-BNO055/ - ...

Vibration sensor ?

Capacity sensor ?

Please help me :D ! Thanks.

Hello Jerome,

I'm also french, working with startup at Euratechnologies, Lille, to help them with BLE and hardware choices and development speedup.

You already pick the easyiest way to develop quickly an efficiently a prototype, as the mbed compiler allows you to develop generic code (meaning it creates an abstraction level, and your code should work for multiple dev platforms without changes).

Also, nRF51-DK seams a good start, even if you could look to the arch ble which have the groove sensor compatibility, and the BLE nano if you want to get that tiny and wearable.

For development, you could use BLE device and BLE API to quickly create a prototype, I suggest you to base your prototype on "Cube Puck", which is an example of accelerometer use by Nordic semi : http://nordicsemiconductor.github.io/puck/tutorials/cube.html

If you are arduino friendly, you should look over I2C interface, and they are here number of examples of sensors examples and libraries, essentially for MPU-6050 and 9250. I suggest you the MPU-9250, as you could find it easilly on a breakout board on ebay for few euros.

For the capacity sensor and the vibrator, you should look at adafruit, they have number of parts you could easilly find on, or the same reference cheaper on eBay.

Thank you Adrien for you reply.

In the mean time, i have already buy the board, the ADXL362 and a vibrator sensor !

I send you a private message.