he LED example demonstrates the use of a read-write characteristic to control a LED through a phone app. The canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_LED

To help you create your own BLE services, we have created this service template. The LED example demonstrates the use of a read-write characteristic to control a LED through a phone app.

The template covers:

  • Setting up advertising and connection states.
  • Assigning UUIDs to the service and its characteristic.
  • Creating an input characteristic: read-write, boolean. This characteristic offers control of the LED.
  • Constructing a service class and adding it to the BLE stack.

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.

  • NOTE:* If you have more than a single mbed board (e.g. nrf51dk or mkit) you can run the BLE_LED and BLE_LEDBlinker at the same time. For more information please refer to the BLE_LEDBlinker demo.

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-LED/raw-file/c6a8f2b3efb6/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 `LED`.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-LED/raw-file/c6a8f2b3efb6/img/scan_results.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-LED/raw-file/c6a8f2b3efb6/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 *LED service* has the UUID `0xA000` and includes the *LED 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-LED/raw-file/c6a8f2b3efb6/img/discovery.png

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

  • Open the write pannel of the *LED state* characteristic.

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-LED/raw-file/c6a8f2b3efb6/img/write_characteristic.png

figure 5 How to read and write a characteristic value using Master Control Panel 4.0.5

  • The characteristic accept a 1 byte value:

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-LED/raw-file/c6a8f2b3efb6/img/write_pannel.png

figure 6 Write characteristic pannel using Master Control Panel 4.0.5

`0x00`: LED ON

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-LED/raw-file/c6a8f2b3efb6/img/LED_ON.png

figure 6 Write characteristic pannel to set the LED on using Master Control Panel 4.0.5

`0x01`: LED OFF

https://developer.mbed.org/teams/mbed-os-examples/code/mbed-os-example-ble-LED/raw-file/c6a8f2b3efb6/img/LED_OFF.png

figure 6 Write characteristic pannel to set the LED off using Master Control Panel 4.0.5

  • Toggle the LED characteristic value and see the LED turn ON or turn OFF according to the value you set.

If you can see the characteristic, and the LED is turned on/off as you toggle its value, the application is working properly.

Changes

RevisionDateWhoCommit message
79:4c62b7c6081a 11 months ago mbed_official Merge pull request #252 from donatieng/mbed_os_update default tip
78:08c7eae77646 16 months ago mbed_official Updating mbed-os to mbed-os-5.11.5
77:cda101593438 16 months ago mbed_official Merge pull request #217 from adbridge/master
76:3f7494ab0f30 17 months ago mbed_official Updating mbed-os to mbed-os-5.11.2
75:f308e60d2a93 18 months ago mbed_official Merge pull request #207 from adbridge/master
74:51fde11a771f 18 months ago mbed_official Merge pull request #208 from ARMmbed/mbed-os-5.11.0-oob
73:3d63a12e85de 19 months ago mbed_official Updating mbed-os to mbed-os-5.10.4
72:b36a60f4b290 20 months ago mbed_official Merge pull request #192 from paul-szczepanek-arm/update-libs
71:112875e67b65 20 months ago mbed_official Merge pull request #189 from ARMmbed/donatieng-patch-1
70:efd6bb972dc4 20 months ago mbed_official Merge pull request #187 from cmonr/master
69:83ded2a8ae51 21 months ago mbed_official Merge pull request #183 from ARMmbed/mbed-os-5.10.0-oob
68:462ee502bc56 22 months ago mbed_official Merge pull request #173 from pan-/use-cordio
67:a593918fd9cc 22 months ago mbed_official Merge pull request #172 from 0xc0170/master
66:c40a89fa5c78 22 months ago mbed_official Updating mbed-os to mbed-os-5.9.5
65:7b9a45791d36 23 months ago mbed_official Merge pull request #168 from cmonr/master
64:22183a041a18 24 months ago mbed_official Merge pull request #166 from cmonr/master
63:98c00bf61979 2018-07-06 mbed_official Merge pull request #163 from adbridge/master
62:46bab7fb8527 2018-06-22 mbed_official Merge pull request #160 from adbridge/master
61:5f76d9799622 2018-06-20 mbed_official Merge pull request #159 from ARMmbed/mbed-os-5.9.0-oob
60:b22168ba7ef2 2018-06-11 mbed_official Merge pull request #158 from adbridge/master
59:962e8666b592 2018-06-05 mbed_official Merge pull request #151 from paul-szczepanek-arm/privacy
58:3633cd179be8 2018-04-04 mbed_official Merge pull request #141 from adbridge/master
57:f49c3bda47a6 2018-04-04 mbed_official Merge pull request #142 from ARMmbed/mbed-os-5.8.0-oob
56:e50bc682bde4 2018-03-23 mbed_official Merge pull request #139 from cmonr/master
55:6ac22205ddb8 2018-03-23 mbed_official Merge pull request #137 from adbridge/master
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53:5b955587a85b 2018-01-31 mbed_official Merge pull request #134 from cmonr/master
52:c90dda03c368 2018-01-17 mbed_official Merge pull request #133 from adbridge/master
51:17d411eaa3e1 2018-01-09 mbed_official Merge pull request #129 from adbridge/master
50:357684a20f90 2018-01-08 mbed_official Merge pull request #132 from pan-/remove-mbedignore
49:bb80bef8bbfb 2017-12-20 mbed_official Merge pull request #126 from ARMmbed/mbed-os-5.7.0-oob
48:43de72457439 2017-12-05 mbed_official Merge pull request #119 from adbridge/master
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45:5df58b883c5e 2017-11-03 mbed_official Merge pull request #110 from 0xc0170/master
44:df8adb3bc797 2017-11-01 mbed_official Merge pull request #112 from marcbonnici/master
43:3249e80f65ba 2017-10-11 mbed_official Merge pull request #108 from adbridge/master
42:5d85db4542a8 2017-09-29 mbed_official Merge pull request #106 from 0xc0170/master
41:f920ea31ae44 2017-09-20 mbed_official Merge pull request #103 from ARMmbed/5.6_sanity
40:aa6c06dc9e99 2017-09-08 mbed_official Merge pull request #102 from adbridge/master
39:3e041017ecd7 2017-08-08 mbed_official Merge pull request #100 from 0xc0170/master
38:f36c230b1b28 2017-07-28 mbed_official Merge pull request #99 from bcostm/add_disco_l475vg
37:7c2cb30d77c6 2017-07-19 mbed_official Merge pull request #97 from 0xc0170/master
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24:1d9d9ffc6417 2017-04-05 mbed_official Merge pull request #72 from pan-/update_bluenrg_ref
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21:27518fd28d50 2017-03-09 mbed_official Merge pull request #66 from ARMmbed/oob_test_mbed-os-5.4
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