The Uniform Resource Identifier Beacon (UriBeacon) defines Bluetooth 4.0 Advertisement Data that contain Web URIs. URIBeacon provides a way for Bluetooth Low Energy devices to discover nearby URIs, for example, provides a way for a user to discover a short URL and then download it on their smartphone.

Dependencies:   BLE_API mbed nRF51822

Fork of BLE_PhysicalWeb by Bluetooth Low Energy

This example demonstrates how to set up and initialize a basic URI Beacon. For a more advanced example of using a URI beacon please see the BLE_PhysicalWeb project. The Google Github Page also gives a great description of what UriBeacons are and how to use them.

Basic Details

URI Beacons are a standard way of providing a URI link in a BLE advertising packet. Website URL's are the most popular URI's. The goal of URI Beacons are to act as a bridge between the physical and digital worlds. Since the URI can be any web capable link the possibilities for use are really endless. The UriBeacons can be thought of as a natural extension of and more useful version of QR codes.

Smartphone App Links

iPhone Physical Web app

Android App

Walkthrough of Physical Web application

Size of URI

The UriBeacon has one purpose, to advertise a web link. Because of the nature of BLE these web links have to be small. In order to provide a nice balance of small and useful the UriBeacon specification has abstracted out the representation of the URI prefix('http://www.', 'https://www.' , ...etc) and suffix ('.com','.org','.edu','.gov' ...etc) to a single byte each. Of the 27 bytes available for a usual BLE payload the UriBeacon has 19 bytes available for the URI. Of these 19bytes one byte must be given to the prefix. That leaves 18 bytes to fit the address and the suffix into. If the suffix used is not one of the standard ones in the UriBeacon specification then each letter will take up 1 byte instead of the entire suffix being abbreviated into a single byte.

Here are the acceptable abbreviations currently available


So for example the address "" would take up 8 bytes. Both "http://www." and ".com" are supported abbreviations so each will be shortened to 1 byte.

Number of BytesData
1"http://www." abbreviated
6"google", 1 byte for each letter
1".com/" abbreviated

An address like "" would take up 11 bytes. Notice that ".ly" is not a supported suffix, so each letter takes up 1 byte.

Number of BytesData
1"http://www." abbreviated

Even addresses with the suffix in the middle are abbreviated, ie "". Notice here that the '.com' is in the middle of an address, it is still shortened to just 1 byte.

Number of BytesData
1"http://www." abbreviated
1".com/" abbreviated

Using UriBeacons with mbed BLE API

Using the UriBeacon with the mbed API is rather simple. Just like any other BLE project you must first initialize the BLE baselayer by creating a ble object.


BLEDevice ble;

Then you pass the BLE object to a UriBeacon config service.


URIBeaconConfigService *uriBeaconConfig;
uriBeaconConfig = new URIBeaconConfigService(ble, "");

Optionally you can then adjust settings of the UriBeacon such as transmission power levels, grabbing verbose debug information and other handy dandy services.


/* Adjust the TX Power Level */
    const int8_t powerLevels[] = {-20, -4, 0, 10};
    uriBeaconConfig->setTxPowerLevels(powerLevels); // Set TX power levels, Lowest(-20), Low(-4), Medium(0), High(10)
    uriBeaconConfig->setTxPowerMode(URIBeaconConfigService::TX_POWER_MODE_LOW); // Set transmission in Low power mode

/* Adjust Beacon Period*/
setBeaconPeriod(1000); // Set beacon to advertise every 1000ms

Other UriBeacon Services

This is just the bare basics of how URI beacons work. There is also a configuration service that allows URI beacons to be updated, locked, and provides other management feature. That is beyond the scope of this example but details can be found in the Technical Details section below.

Technical Details

For more details on how URI beacons work please see these websites:
UriBeacon Github Project : the github home for all things UriBeacon (maintained by google)
UriBeacon Specification : lots of good technical details
UriBeacon configuration service - This is a service that pairs with the UriBeacon that allows changing the URI's, locking them, and some other cool features. This service is not detailed in this example application.
Android App : smartphone application to view nearby UriBeacons.
iOS App : Sample code for using UriBeacons with iOS.
The PhysicalWeb Project : a project that the UriBeacon is central to.

In case you're really interested here is a diagram that nicely sums up how the 27bytes of advertising data payload are used.

Fri Mar 13 10:13:18 2015 +0000
updated to the latest from BLE_API.; Moving persistence checking into the Nordic specific flash adaptor code.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rgrover1 14:868a1207022d 1 /* mbed Microcontroller Library
rgrover1 14:868a1207022d 2 * Copyright (c) 2006-2013 ARM Limited
rgrover1 0:790a27ffc99b 3 *
rgrover1 0:790a27ffc99b 4 * Licensed under the Apache License, Version 2.0 (the "License");
rgrover1 0:790a27ffc99b 5 * you may not use this file except in compliance with the License.
rgrover1 0:790a27ffc99b 6 * You may obtain a copy of the License at
rgrover1 0:790a27ffc99b 7 *
rgrover1 13:b82d8db73633 8 *
rgrover1 0:790a27ffc99b 9 *
rgrover1 0:790a27ffc99b 10 * Unless required by applicable law or agreed to in writing, software
rgrover1 0:790a27ffc99b 11 * distributed under the License is distributed on an "AS IS" BASIS,
rgrover1 0:790a27ffc99b 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rgrover1 0:790a27ffc99b 13 * See the License for the specific language governing permissions and
rgrover1 0:790a27ffc99b 14 * limitations under the License.
rgrover1 0:790a27ffc99b 15 */
rgrover1 0:790a27ffc99b 16
rgrover1 0:790a27ffc99b 17 #include "mbed.h"
rgrover1 0:790a27ffc99b 18 #include "BLEDevice.h"
rgrover1 13:b82d8db73633 19 #include "URIBeaconConfigService.h"
rgrover1 11:c77cc2b74101 20 #include "DFUService.h"
rgrover1 11:c77cc2b74101 21 #include "DeviceInformationService.h"
rgrover1 16:1daa78939a3b 22 #include "ConfigParamsPersistence.h"
rgrover1 13:b82d8db73633 23
rgrover1 0:790a27ffc99b 24 BLEDevice ble;
rgrover1 13:b82d8db73633 25 URIBeaconConfigService *uriBeaconConfig;
rgrover1 13:b82d8db73633 26
rgrover1 17:e2c0a1696e39 27 /**
rgrover1 17:e2c0a1696e39 28 * URIBeaconConfig service can operate in two modes: a configuration mode which
rgrover1 17:e2c0a1696e39 29 * allows a user to update settings over a connection; and normal URIBeacon mode
rgrover1 17:e2c0a1696e39 30 * which involves advertising a URI. Constructing an object from URIBeaconConfig
rgrover1 17:e2c0a1696e39 31 * service sets up advertisements for the configuration mode. It is then up to
rgrover1 17:e2c0a1696e39 32 * the application to switch to URIBeacon mode based on some timeout.
rgrover1 17:e2c0a1696e39 33 *
rgrover1 17:e2c0a1696e39 34 * The following help with this switch.
rgrover1 17:e2c0a1696e39 35 */
rgrover1 17:e2c0a1696e39 36 static const int CONFIG_ADVERTISEMENT_TIMEOUT_SECONDS = 60; // Duration after power-on that config service is available.
rgrover1 17:e2c0a1696e39 37 Ticker configAdvertisementTimeoutTicker;
rgrover1 17:e2c0a1696e39 38
rgrover1 17:e2c0a1696e39 39 /**
rgrover1 17:e2c0a1696e39 40 * Stop advertising the UriBeaconConfig Service after a delay; and switch to normal URIBeacon.
rgrover1 17:e2c0a1696e39 41 */
rgrover1 17:e2c0a1696e39 42 void timeout(void)
rgrover1 17:e2c0a1696e39 43 {
rgrover1 17:e2c0a1696e39 44 Gap::GapState_t state;
rgrover1 17:e2c0a1696e39 45 state = ble.getGapState();
rgrover1 17:e2c0a1696e39 46 if (!state.connected) { /* don't switch if we're in a connected state. */
rgrover1 17:e2c0a1696e39 47 uriBeaconConfig->setupURIBeaconAdvertisements();
rgrover1 17:e2c0a1696e39 48 ble.startAdvertising();
rgrover1 17:e2c0a1696e39 49
rgrover1 17:e2c0a1696e39 50 configAdvertisementTimeoutTicker.detach(); /* disable the callback from the timeout Ticker. */
rgrover1 17:e2c0a1696e39 51 }
rgrover1 17:e2c0a1696e39 52 }
rgrover1 17:e2c0a1696e39 53
rgrover1 17:e2c0a1696e39 54 /**
rgrover1 17:e2c0a1696e39 55 * Callback triggered upon a disconnection event. Needs to re-enable advertisements.
rgrover1 17:e2c0a1696e39 56 */
rgrover1 16:1daa78939a3b 57 void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason)
rgrover1 16:1daa78939a3b 58 {
rgrover1 6:31b65d4ea67d 59 ble.startAdvertising();
rgrover1 6:31b65d4ea67d 60 }
rgrover1 0:790a27ffc99b 61
rgrover1 0:790a27ffc99b 62 int main(void)
rgrover1 0:790a27ffc99b 63 {
rgrover1 0:790a27ffc99b 64 ble.init();
rgrover1 6:31b65d4ea67d 65 ble.onDisconnection(disconnectionCallback);
rgrover1 13:b82d8db73633 66
rgrover1 16:1daa78939a3b 67 /*
rgrover1 16:1daa78939a3b 68 * Load parameters from (platform specific) persistent storage. Parameters
rgrover1 16:1daa78939a3b 69 * can be set to non-default values while the URIBeacon is in configuration
rgrover1 16:1daa78939a3b 70 * mode (within the first 60 seconds of power-up). Thereafter, parameters
rgrover1 16:1daa78939a3b 71 * get copied out to persistent storage before switching to normal URIBeacon
rgrover1 16:1daa78939a3b 72 * operation.
rgrover1 16:1daa78939a3b 73 */
rgrover1 16:1daa78939a3b 74 URIBeaconConfigService::Params_t params;
rgrover1 17:e2c0a1696e39 75 bool fetchedFromPersistentStorage = loadURIBeaconConfigParams(&params);
rgrover1 13:b82d8db73633 76
rgrover1 16:1daa78939a3b 77 /* Initialize a URIBeaconConfig service providing config params, default URI, and power levels. */
rgrover1 16:1daa78939a3b 78 static URIBeaconConfigService::PowerLevels_t defaultAdvPowerLevels = {-20, -4, 0, 10}; // Values for ADV packets related to firmware levels
rgrover1 17:e2c0a1696e39 79 uriBeaconConfig = new URIBeaconConfigService(ble, params, !fetchedFromPersistentStorage, "", defaultAdvPowerLevels);
rgrover1 13:b82d8db73633 80 if (!uriBeaconConfig->configuredSuccessfully()) {
rgrover1 6:31b65d4ea67d 81 error("failed to accommodate URI");
rgrover1 6:31b65d4ea67d 82 }
rgrover1 17:e2c0a1696e39 83 configAdvertisementTimeoutTicker.attach(timeout, CONFIG_ADVERTISEMENT_TIMEOUT_SECONDS);
rgrover1 0:790a27ffc99b 84
rgrover1 13:b82d8db73633 85 // Setup auxiliary services to allow over-the-air firmware updates, etc
rgrover1 13:b82d8db73633 86 DFUService dfu(ble);
rgrover1 16:1daa78939a3b 87 DeviceInformationService deviceInfo(ble, "ARM", "UriBeacon", "SN1", "hw-rev1", "fw-rev1", "soft-rev1");
rgrover1 11:c77cc2b74101 88
rgrover1 16:1daa78939a3b 89 ble.startAdvertising(); /* Set the whole thing in motion. After this call a GAP central can scan the URIBeaconConfig
rgrover1 16:1daa78939a3b 90 * service, which then automatically switches to the URIBeacon after a timeout. */
rgrover1 0:790a27ffc99b 91
rgrover1 0:790a27ffc99b 92 while (true) {
rgrover1 0:790a27ffc99b 93 ble.waitForEvent();
rgrover1 0:790a27ffc99b 94 }
rgrover1 0:790a27ffc99b 95 }