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.

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

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

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

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

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

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.

Committer:
mbed_official
Date:
Tue Aug 08 14:15:07 2017 +0100
Revision:
41:43801c2d0a0c
Parent:
3:488ecd009a27
Merge pull request #100 from 0xc0170/master

Updating mbed-os to mbed-os-5.5.4
.
Commit copied from https://github.com/ARMmbed/mbed-os-example-ble

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official4:52bffaff7f0b 1{
mbed_official4:52bffaff7f0b 2 "name": "ble-batterylevel",
mbed_official4:52bffaff7f0b 3 "version": "0.0.1",
mbed_official4:52bffaff7f0b 4 "description": "An example of creating and updating a simple GATT Service using the BLE_API",
mbed_official4:52bffaff7f0b 5 "licenses": [
mbed_official4:52bffaff7f0b 6 {
mbed_official4:52bffaff7f0b 7 "url": "https://spdx.org/licenses/Apache-2.0",
mbed_official4:52bffaff7f0b 8 "type": "Apache-2.0"
mbed_official4:52bffaff7f0b 9 }
mbed_official4:52bffaff7f0b 10 ],
mbed_official4:52bffaff7f0b 11 "dependencies": {
mbed_official4:52bffaff7f0b 12 "ble": "^2.0.0"
mbed_official4:52bffaff7f0b 13 },
mbed_official4:52bffaff7f0b 14 "targetDependencies": {},
mbed_official4:52bffaff7f0b 15 "bin": "./source"
mbed_official4:52bffaff7f0b 16}