Exploring BLE through nRF51 DK development board

We are currently working on nRF51DK, a single-board development kit for Bluetooth low energy, ANT  and 2.4 GHz proprietary applications by Nordic Semiconductors.

                                                       Figure 1 nRF51DK development kit content

BLE as mentioned, stands for Bluetooth Low Energy, and is also known as Bluetooth Smart a subset of Bluetooth 4.0 specification. It is widely used in developing IoT devices as it is a good platform due to its less power consumption,cost and reduced data rate in comparison to Bluetooth Classic.

BLE operated devices work for longer periods on power sources such as coin cell batteries like iBeacons.

We have used beacons in our application and we will be covering it in the upcoming posts.

   

The support for Bluetooth 4.0 and Bluetooth Low Energy is available on most major platforms as of the versions listed below:

•     iOS5+ (iOS7+ preferred)

•     Android 4.3+ (numerous bug fixes in 4.4+)

•     Apple OS X 10.6+

•     Windows 8 (XP, Vista and 7 only support Bluetooth 2.1)

•     GNU/Linux Vanilla BlueZ 4.93+

nRF51DK:

We are using BLE in our final year project and for that we are using nRF51DK board.The board is fitted with the nRF51422 chip and on board interface MCU as shown in the figure below.

nRF51422 is ARM Cortex- M0 32 bit processor, the MCU is used for sending the hex file to the on board bluetooth chip (referring the ARM Cortex processor). The board has Debug In terminal pins for programming the on board bluetooth chip using another MCU and Debug Out terminal pins to program other bluetooth chip modules using the on board MCU other than the on board bluetooth chip.
These options are quite helpful in long run and for varied applications. 

The project is built on ARM processor and mbed as the compiler. We can also use Keil, but for that you need to download requisite libraries.

mbed is easy to use online compiler for beginners and hobbyists who wish to do projects on ARM processors. There are lot of other boards available, along with their libraries.

Do visit the links attached at the end to explore more additional features of board as well as mbed. 

                                                                Figure 2 Block diagram for nRF51DK 

In order to begin working with BLE, there are two important concepts one must know:

1. GAP Advertising

2. GATT

We will cover these two in the next article along with application of scanner for beacons. 

Useful Links:

http://www.mbed.org/

https://www.nordicsemi.com/eng/Products/nRF51-DK