BLE_Button is a BLE service template. It handles a read-only characteristic with a simple input (boolean values). The input's source is the button on the board itself - the characteristic's value changes when the button is pressed or released. The canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_Button

BLE_Button is a BLE service template. It handles a read-only characteristic with a simple input (boolean values). The input's source is the button on the board itself - the characteristic's value changes when the button is pressed or released.

The template covers:

  • Setting up advertising and connection modes.
  • Creating an input characteristic: read-only, boolean, with notifications.
  • Constructing a service class and adding it to the BLE stack.
  • Assigning UUIDs to the service and its characteristic.
  • Pushing notifications when the characteristic's value changes.

Running the application

Requirements

The sample application can be seen on any BLE scanner on a smartphone. If you don't have a scanner on your phone, please install :

- nRF Master Control Panel for Android.

- LightBlue for iPhone.

Hardware requirements are in the main readme.

Building instructions

Building with mbed CLI

If you'd like to use mbed CLI to build this, then you should refer to the main readme. The instructions here relate to using the developer.mbed.org Online Compiler

In order to build this example in the mbed Online Compiler, first import the example using the ‘Import’ button on the right hand side.

Next, select a platform to build for. This must either be a platform that supports BLE, for example the NRF51-DK, or one of the following:

List of platforms supporting Bluetooth Low Energy

Or you must also add a piece of hardware and the supporting library that includes a Bluetooth Low Energy driver for that hardware, for example the K64F or NUCLEO_F401RE with the X-NUCLEO-IDB05A1

List of components supporting Bluetooth Low Energy.

Once you have selected your platform, compile the example and drag and drop the resulting binary onto your board.

For general instructions on using the mbed Online Compiler, please see the mbed Handbook

Checking for success

Note: Screens captures depicted below show what is expected from this example if the scanner used is nRF Master Control Panel version 4.0.5. If you encounter any difficulties consider trying another scanner or another version of nRF Master Control Panel. Alternative scanners may require reference to their manuals.

  • Build the application and install it on your board as explained in the building instructions.
  • Open the BLE scanner on your phone.
  • Start a scan.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/start_scan.png

figure 1 How to start scan using nRF Master Control Panel 4.0.5

  • Find your device; it should appear with the name `Button` in the scanner.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/scan_results.png

figure 2 Scan results using nRF Master Control Panel 4.0.5

  • Establish a connection with the device.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/connection.png

figure 3 How to establish a connection using Master Control Panel 4.0.5

  • Discover the services and the characteristics on the device. The Button service has the UUID `0xA000` and includes the Button state characteristic which has the UUID `0xA001`. Depending on your scanner, non standard 16-bit UUID's can be displayed as 128-bit UUID's. If it is the case the following format will be used: `0000XXXX-0000-1000-8000-00805F9B34FB` where `XXXX` is the hexadecimal representation of the 16-bit UUID value.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/discovery.png

figure 4 Representation of the Button service using Master Control Panel 4.0.5

  • Register for the notifications sent by the button state characteristic then the scanner will automatically receive a notification containing the new state of the button every time the state of the button changes.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/register_to_notifications.png

figure 5 How to register to notifications using Master Control Panel 4.0.5

  • Pressing Button 1 on your board updates the state of the button and sends a notification to the scanner. The new state of the button characteristic value should be equal to 0x01.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/button_pressed.png

figure 6 Notification of button pressed using Master Control Panel 4.0.5

  • Releasing Button 1 on your board updates the state of the button and sends a notification to the scanner. The new state of the button characteristic value should be equal to 0x00.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-Button/raw-file/3fe9d5124576/img/button_depressed.png

figure 7 Notification of button depressed using Master Control Panel 4.0.5

Committer:
Vincent Coubard
Date:
Tue Jul 26 14:37:15 2016 +0100
Revision:
0:3fe9d5124576
Child:
1:cd85f873e10d
Update example at tag mbed-os-5.0.1-rc1

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Vincent Coubard 0:3fe9d5124576 1 BLE_Button is a BLE service template. It handles a read-only characteristic with a simple input (boolean values). The input's source is the button on the board itself - the characteristic's value changes when the button is pressed or released.
Vincent Coubard 0:3fe9d5124576 2
Vincent Coubard 0:3fe9d5124576 3 The template covers:
Vincent Coubard 0:3fe9d5124576 4
Vincent Coubard 0:3fe9d5124576 5 1. Setting up advertising and connection modes.
Vincent Coubard 0:3fe9d5124576 6
Vincent Coubard 0:3fe9d5124576 7 1. Creating an input characteristic: read-only, boolean, with notifications.
Vincent Coubard 0:3fe9d5124576 8
Vincent Coubard 0:3fe9d5124576 9 1. Constructing a service class and adding it to the BLE stack.
Vincent Coubard 0:3fe9d5124576 10
Vincent Coubard 0:3fe9d5124576 11 1. Assigning UUIDs to the service and its characteristic.
Vincent Coubard 0:3fe9d5124576 12
Vincent Coubard 0:3fe9d5124576 13 1. Pushing notifications when the characteristic's value changes.
Vincent Coubard 0:3fe9d5124576 14
Vincent Coubard 0:3fe9d5124576 15 # Running the application
Vincent Coubard 0:3fe9d5124576 16
Vincent Coubard 0:3fe9d5124576 17 ## Requirements
Vincent Coubard 0:3fe9d5124576 18
Vincent Coubard 0:3fe9d5124576 19 The sample application can be seen on any BLE scanner on a smartphone. If you don't have a scanner on your phone, please install :
Vincent Coubard 0:3fe9d5124576 20
Vincent Coubard 0:3fe9d5124576 21 - [nRF Master Control Panel](https://play.google.com/store/apps/details?id=no.nordicsemi.android.mcp) for Android.
Vincent Coubard 0:3fe9d5124576 22
Vincent Coubard 0:3fe9d5124576 23 - [LightBlue](https://itunes.apple.com/gb/app/lightblue-bluetooth-low-energy/id557428110?mt=8) for iPhone.
Vincent Coubard 0:3fe9d5124576 24
Vincent Coubard 0:3fe9d5124576 25 Hardware requirements are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md).
Vincent Coubard 0:3fe9d5124576 26
Vincent Coubard 0:3fe9d5124576 27 ## Building instructions
Vincent Coubard 0:3fe9d5124576 28
Vincent Coubard 0:3fe9d5124576 29 Building instructions for all samples are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md).
Vincent Coubard 0:3fe9d5124576 30
Vincent Coubard 0:3fe9d5124576 31 ## Checking for success
Vincent Coubard 0:3fe9d5124576 32
Vincent Coubard 0:3fe9d5124576 33 **Note:** Screens captures depicted below show what is expected from this example if the scanner used is *nRF Master Control Panel* version 4.0.5. If you encounter any difficulties consider trying another scanner or another version of nRF Master Control Panel. Alternative scanners may require reference to their manuals.
Vincent Coubard 0:3fe9d5124576 34
Vincent Coubard 0:3fe9d5124576 35 1. Build the application and install it on your board as explained in the building instructions.
Vincent Coubard 0:3fe9d5124576 36 1. Open the BLE scanner on your phone.
Vincent Coubard 0:3fe9d5124576 37 1. Start a scan.
Vincent Coubard 0:3fe9d5124576 38
Vincent Coubard 0:3fe9d5124576 39 ![](img/start_scan.png)
Vincent Coubard 0:3fe9d5124576 40
Vincent Coubard 0:3fe9d5124576 41 **figure 1** How to start scan using nRF Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 42
Vincent Coubard 0:3fe9d5124576 43 1. Find your device; it should appear with the name `Button` in the scanner.
Vincent Coubard 0:3fe9d5124576 44
Vincent Coubard 0:3fe9d5124576 45 ![](img/scan_results.png)
Vincent Coubard 0:3fe9d5124576 46
Vincent Coubard 0:3fe9d5124576 47 **figure 2** Scan results using nRF Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 48
Vincent Coubard 0:3fe9d5124576 49 1. Establish a connection with the device.
Vincent Coubard 0:3fe9d5124576 50
Vincent Coubard 0:3fe9d5124576 51 ![](img/connection.png)
Vincent Coubard 0:3fe9d5124576 52
Vincent Coubard 0:3fe9d5124576 53 **figure 3** How to establish a connection using Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 54
Vincent Coubard 0:3fe9d5124576 55 1. Discover the services and the characteristics on the device. The *Button service* has the UUID `0xA000` and includes the *Button state characteristic* which has the UUID `0xA001`. Depending on your scanner, non standard 16-bit UUID's can be displayed as 128-bit UUID's. If it is the case the following format will be used: `0000XXXX-0000-1000-8000-00805F9B34FB` where `XXXX` is the hexadecimal representation of the 16-bit UUID value.
Vincent Coubard 0:3fe9d5124576 56
Vincent Coubard 0:3fe9d5124576 57 ![](img/discovery.png)
Vincent Coubard 0:3fe9d5124576 58
Vincent Coubard 0:3fe9d5124576 59 **figure 4** Representation of the Button service using Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 60
Vincent Coubard 0:3fe9d5124576 61 1. Register for the notifications sent by the button state characteristic then the scanner will automatically receive a notification containing the new state of the button every time the state of the button changes.
Vincent Coubard 0:3fe9d5124576 62
Vincent Coubard 0:3fe9d5124576 63 ![](img/register_to_notifications.png)
Vincent Coubard 0:3fe9d5124576 64
Vincent Coubard 0:3fe9d5124576 65 **figure 5** How to register to notifications using Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 66
Vincent Coubard 0:3fe9d5124576 67
Vincent Coubard 0:3fe9d5124576 68 1. Pressing Button 1 on your board updates the state of the button and sends a notification to the scanner. The new state of the button characteristic value should be equal to 0x01.
Vincent Coubard 0:3fe9d5124576 69
Vincent Coubard 0:3fe9d5124576 70 ![](img/button_pressed.png)
Vincent Coubard 0:3fe9d5124576 71
Vincent Coubard 0:3fe9d5124576 72 **figure 6** Notification of button pressed using Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 73
Vincent Coubard 0:3fe9d5124576 74 1. Releasing Button 1 on your board updates the state of the button and sends a notification to the scanner. The new state of the button characteristic value should be equal to 0x00.
Vincent Coubard 0:3fe9d5124576 75
Vincent Coubard 0:3fe9d5124576 76 ![](img/button_depressed.png)
Vincent Coubard 0:3fe9d5124576 77
Vincent Coubard 0:3fe9d5124576 78 **figure 7** Notification of button depressed using Master Control Panel 4.0.5
Vincent Coubard 0:3fe9d5124576 79