This example creates and updates a standard Battery Level service containing a single GATT characteristic. The battery service transmits a device's battery level in percentage, with 100% being a fully charged battery and 0% being a fully drained battery. The canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_BatteryLevel

This example creates and updates a standard Battery Level service containing a single GATT characteristic.

The battery service transmits a device's battery level in percentage, with 100% being a fully charged battery and 0% being a fully drained battery.

Although the sample application runs on a BLE device, it doesn't show the device's real battery level (because that changes very slowly and will make for a dull example). Instead, it transmits a fake battery level that starts at 50% (half charged). Every half second, it increments the battery level, going in single increments until reaching 100% (as if the battery is charging). It then drops down to 20% to start incrementing again.

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-BatteryLevel/raw-file/a5ac4bf2e468/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 `BATTERY`.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-BatteryLevel/raw-file/a5ac4bf2e468/img/scan_result.png

figure 2 Scan results using nRF Master Control Panel 4.0.5

  • Establish a connection with your device.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-BatteryLevel/raw-file/a5ac4bf2e468/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 *Battery service* has the UUID 0x180F and includes the *Battery level* characteristic which has the UUID 0x2A19.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-BatteryLevel/raw-file/a5ac4bf2e468/img/discovery.png

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

  • Register for the notifications sent by the *Battery level* characteristic.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-BatteryLevel/raw-file/a5ac4bf2e468/img/register_to_notifications.png

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

  • You should see the battery level value change every half second. It begins at 50, goes up to 100 (in steps of 1), resets to 20 and so on.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-BatteryLevel/raw-file/a5ac4bf2e468/img/notifications.png

figure 6 Notifications view using Master Control Panel 4.0.5

If you can see the characteristic, and if its value is incrementing correctly, the application is working properly.

Changes

RevisionDateWhoCommit message
81:99e70947653f 2 months ago mbed_official Merge pull request #252 from donatieng/mbed_os_update default tip
80:1170721a1db6 7 months ago mbed_official Updating mbed-os to mbed-os-5.11.5
79:816f08ee21bd 7 months ago mbed_official Merge pull request #217 from adbridge/master
78:b300982f35aa 8 months ago mbed_official Updating mbed-os to mbed-os-5.11.2
77:634599d24f93 9 months ago mbed_official Merge pull request #207 from adbridge/master
76:e489712bcbcf 9 months ago mbed_official Merge pull request #208 from ARMmbed/mbed-os-5.11.0-oob
75:a91805e80107 10 months ago mbed_official Updating mbed-os to mbed-os-5.10.4
74:eee554d9917b 11 months ago mbed_official Merge pull request #192 from paul-szczepanek-arm/update-libs
73:e76cb6fa4310 11 months ago mbed_official Merge pull request #189 from ARMmbed/donatieng-patch-1
72:15a6111a679e 11 months ago mbed_official Merge pull request #187 from cmonr/master
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70:5cf292205001 13 months ago mbed_official Merge pull request #173 from pan-/use-cordio
69:3505c21fe0fc 13 months ago mbed_official Merge pull request #172 from 0xc0170/master
68:6b40c380545f 13 months ago mbed_official Updating mbed-os to mbed-os-5.9.5
67:2a65e8c6ab62 14 months ago mbed_official Merge pull request #168 from cmonr/master
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65:a7d40a1e5bb3 15 months ago mbed_official Merge pull request #163 from adbridge/master
64:31a307a8a873 16 months ago mbed_official Merge pull request #160 from adbridge/master
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62:42a62fe25296 16 months ago mbed_official Merge pull request #158 from adbridge/master
61:2430255789dc 16 months ago mbed_official Initial commit.
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