This application shows how to use GAP to transmit a simple value to disconnected peer listening for advertisement every time that a value is updated. The canonical source for this example lives at: https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_GAPButton

Button count over GAP

This application shows how to use GAP to transmit a simple value to disconnected peer listening for advertisement every time that a value is updated:

  • The value is a count of how many times a button on the device was pressed (the code actually monitors the button's releases, not press downs).
  • We transmit the value in the SERVICE_DATA field of the advertising payload.

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-GAPButton/raw-file/8f898b781de2/img/start_scan.png

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

  • Find your device; it should be named `GAPButton`; and look at the advertisement broadcasted by your device (there is no need to connect to your device).

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-GAPButton/raw-file/8f898b781de2/img/discovery.png

figure 2 Scan results using nRF Master Control Panel 4.0.5.

  • The Service Data field of the advertisement packet broadcasted by your device reflects the button press count. The starting value is 0.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-GAPButton/raw-file/8f898b781de2/img/initial_state.png

figure 3 Initial state of the button using nRF Master Control Panel 4.0.5.

  • Press the button on the device.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-GAPButton/raw-file/8f898b781de2/img/first_press.png

figure 3 State after 1 button press using nRF Master Control Panel 4.0.5.

  • The Service Data field value of the advertisement packet should change every time you press the button.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-GAPButton/raw-file/8f898b781de2/img/result.png

figure 3 State after 6 button press using nRF Master Control Panel 4.0.5.

Note

Since broadcasting is not reliable and your phone may scan intermittently, it is possible that your phone will miss button updates.

Committer:
mbed_official
Date:
Thu Jul 28 23:14:40 2016 +0100
Revision:
1:7f4e41bacb3c
Parent:
0:8f898b781de2
Child:
2:e532bbe3fd8e
Merge branch 'master' of https://github.com/ARMmbed/mbed-os-example-ble


Commit copied from ./src/github.com/ARMmbed/mbed-os-example-ble

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 1:7f4e41bacb3c 1 # Button count over GAP
mbed_official 1:7f4e41bacb3c 2
mbed_official 1:7f4e41bacb3c 3 This application shows how to use GAP to transmit a simple value to disconnected peer listening for advertisement every time that a value is updated:
mbed_official 1:7f4e41bacb3c 4
mbed_official 1:7f4e41bacb3c 5 1. The value is a count of how many times a button on the device was pressed (the code actually monitors the button's releases, not press downs).
mbed_official 1:7f4e41bacb3c 6
mbed_official 1:7f4e41bacb3c 7 1. We transmit the value in the SERVICE_DATA field of the advertising payload.
mbed_official 1:7f4e41bacb3c 8
mbed_official 1:7f4e41bacb3c 9 # Running the application
mbed_official 1:7f4e41bacb3c 10
mbed_official 1:7f4e41bacb3c 11 ## Requirements
mbed_official 1:7f4e41bacb3c 12
mbed_official 1:7f4e41bacb3c 13 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 :
mbed_official 1:7f4e41bacb3c 14
mbed_official 1:7f4e41bacb3c 15 - [nRF Master Control Panel](https://play.google.com/store/apps/details?id=no.nordicsemi.android.mcp) for Android.
mbed_official 1:7f4e41bacb3c 16
mbed_official 1:7f4e41bacb3c 17 - [LightBlue](https://itunes.apple.com/gb/app/lightblue-bluetooth-low-energy/id557428110?mt=8) for iPhone.
mbed_official 1:7f4e41bacb3c 18
mbed_official 1:7f4e41bacb3c 19 Hardware requirements are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md).
mbed_official 1:7f4e41bacb3c 20
mbed_official 1:7f4e41bacb3c 21 ## Building instructions
mbed_official 1:7f4e41bacb3c 22
mbed_official 1:7f4e41bacb3c 23 Building instructions for all samples are in the [main readme](https://github.com/ARMmbed/mbed-os-example-ble/blob/master/README.md).
mbed_official 1:7f4e41bacb3c 24
mbed_official 1:7f4e41bacb3c 25 ## Checking for success
mbed_official 1:7f4e41bacb3c 26
mbed_official 1:7f4e41bacb3c 27 **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.
mbed_official 1:7f4e41bacb3c 28
mbed_official 1:7f4e41bacb3c 29 1. Build the application and install it on your board as explained in the building instructions.
mbed_official 1:7f4e41bacb3c 30
mbed_official 1:7f4e41bacb3c 31 1. Open the BLE scanner on your phone.
mbed_official 1:7f4e41bacb3c 32
mbed_official 1:7f4e41bacb3c 33 1. Start a scan.
mbed_official 1:7f4e41bacb3c 34
mbed_official 1:7f4e41bacb3c 35 ![](img/start_scan.png)
mbed_official 1:7f4e41bacb3c 36
mbed_official 1:7f4e41bacb3c 37 **figure 1** How to start scan using nRF Master Control Panel 4.0.5.
mbed_official 1:7f4e41bacb3c 38
mbed_official 1:7f4e41bacb3c 39 1. Find your device; it should be named `GAPButton`; and look at the advertisement broadcasted by your device (there is no need to connect to your device).
mbed_official 1:7f4e41bacb3c 40
mbed_official 1:7f4e41bacb3c 41 ![](img/discovery.png)
mbed_official 1:7f4e41bacb3c 42
mbed_official 1:7f4e41bacb3c 43 **figure 2** Scan results using nRF Master Control Panel 4.0.5.
mbed_official 1:7f4e41bacb3c 44
mbed_official 1:7f4e41bacb3c 45 1. The Service Data field of the advertisement packet broadcasted by your device reflects the button press count. The starting value is 0.
mbed_official 1:7f4e41bacb3c 46
mbed_official 1:7f4e41bacb3c 47 ![](img/initial_state.png)
mbed_official 1:7f4e41bacb3c 48
mbed_official 1:7f4e41bacb3c 49 **figure 3** Initial state of the button using nRF Master Control Panel 4.0.5.
mbed_official 1:7f4e41bacb3c 50
mbed_official 1:7f4e41bacb3c 51 1. Press the button on the device.
mbed_official 1:7f4e41bacb3c 52
mbed_official 1:7f4e41bacb3c 53 ![](img/first_press.png)
mbed_official 1:7f4e41bacb3c 54
mbed_official 1:7f4e41bacb3c 55 **figure 3** State after 1 button press using nRF Master Control Panel 4.0.5.
mbed_official 1:7f4e41bacb3c 56
mbed_official 1:7f4e41bacb3c 57 1. The Service Data field value of the advertisement packet should change every time you press the button.
mbed_official 1:7f4e41bacb3c 58
mbed_official 1:7f4e41bacb3c 59 ![](img/result.png)
mbed_official 1:7f4e41bacb3c 60
mbed_official 1:7f4e41bacb3c 61 **figure 3** State after 6 button press using nRF Master Control Panel 4.0.5.
mbed_official 1:7f4e41bacb3c 62
mbed_official 1:7f4e41bacb3c 63 ## Note
mbed_official 1:7f4e41bacb3c 64
mbed_official 1:7f4e41bacb3c 65 Since broadcasting is not reliable and your phone may scan intermittently, it is possible that your phone will miss button updates.