mbed-os-examples / Mbed OS mbed-os-example-ble-EddystoneObserver

The Eddystone Observer scans for Eddystone beacons that are running the Eddystone Service example (see there for general information about Eddystone beacons). It reads the advertising packets broadcast by these beacons, and prints a human-readable version of the advertised URLs to the serial console. he canonical source for this example lives at https://github.com/ARMmbed/mbed-os-example-ble/tree/master/BLE_EddystoneObserver

The Eddystone Observer scans for Eddystone beacons that are running the Eddystone Service example (see there for general information about Eddystone beacons). It reads the advertising packets broadcast by these beacons, and prints a human-readable version of the advertised URLs to the serial console.

Running the application

Requirements

General hardware information is in the main readme.

This sample requires two devices - one to broadcast the beacon and one to scan for the broadcast. If you have more devices, you can use them as extra beacons.

You need a terminal program to listen to the observer's output through a serial port. You can download one, for example:

  • Tera Term for Windows.
  • CoolTerm for Mac OS X.
  • GNU Screen for Linux.

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-IDB04A1

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

  • Build the Eddystone Observer application and install it on your board as explained in the building instructions. Leave the board connected to your computer.

Checking console output

To see the application's output:

  • Check which serial port your Eddystone Observer is connected to.
  • Run a terminal program with the correct serial port and the baud rate set to 9600. For example, to use GNU Screen, run: ``screen /dev/tty.usbmodem1412 9600``.
  • The Eddystone Observer should start printing URLs of nearby Eddystone beacons to the terminal.

source/main.cpp@1:d839eae15f56, 2016-07-28 (annotated)

Committer:
mbed_official
Date:
Thu Jul 28 23:14:32 2016 +0100
Revision:
1:d839eae15f56
Parent:
0:932f719b42d5
Child:
2:6a3a66fd3889
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:d839eae15f56 1 /* mbed Microcontroller Library
mbed_official 1:d839eae15f56 2 * Copyright (c) 2006-2013 ARM Limited
mbed_official 1:d839eae15f56 3 *
mbed_official 1:d839eae15f56 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 1:d839eae15f56 5 * you may not use this file except in compliance with the License.
mbed_official 1:d839eae15f56 6 * You may obtain a copy of the License at
mbed_official 1:d839eae15f56 7 *
mbed_official 1:d839eae15f56 8 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 1:d839eae15f56 9 *
mbed_official 1:d839eae15f56 10 * Unless required by applicable law or agreed to in writing, software
mbed_official 1:d839eae15f56 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 1:d839eae15f56 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 1:d839eae15f56 13 * See the License for the specific language governing permissions and
mbed_official 1:d839eae15f56 14 * limitations under the License.
mbed_official 1:d839eae15f56 15 */
mbed_official 1:d839eae15f56 16
mbed_official 1:d839eae15f56 17 #include <mbed-events/events.h>
mbed_official 1:d839eae15f56 18 #include "mbed.h"
mbed_official 1:d839eae15f56 19 #include "ble/BLE.h"
mbed_official 1:d839eae15f56 20
mbed_official 1:d839eae15f56 21 static const int URI_MAX_LENGTH = 18; // Maximum size of service data in ADV packets
mbed_official 1:d839eae15f56 22
mbed_official 1:d839eae15f56 23 static EventQueue eventQueue(
mbed_official 1:d839eae15f56 24 /* event count */ 16 * /* event size */ 32
mbed_official 1:d839eae15f56 25 );
mbed_official 1:d839eae15f56 26
mbed_official 1:d839eae15f56 27 DigitalOut led1(LED1, 1);
mbed_official 1:d839eae15f56 28
mbed_official 1:d839eae15f56 29 void periodicCallback(void)
mbed_official 1:d839eae15f56 30 {
mbed_official 1:d839eae15f56 31 led1 = !led1; /* Do blinky on LED1 while we're waiting for BLE events */
mbed_official 1:d839eae15f56 32 }
mbed_official 1:d839eae15f56 33
mbed_official 1:d839eae15f56 34 void decodeURI(const uint8_t* uriData, const size_t uriLen)
mbed_official 1:d839eae15f56 35 {
mbed_official 1:d839eae15f56 36 const char *prefixes[] = {
mbed_official 1:d839eae15f56 37 "http://www.",
mbed_official 1:d839eae15f56 38 "https://www.",
mbed_official 1:d839eae15f56 39 "http://",
mbed_official 1:d839eae15f56 40 "https://",
mbed_official 1:d839eae15f56 41 "urn:uuid:"
mbed_official 1:d839eae15f56 42 };
mbed_official 1:d839eae15f56 43 const size_t NUM_PREFIXES = sizeof(prefixes) / sizeof(char *);
mbed_official 1:d839eae15f56 44 const char *suffixes[] = {
mbed_official 1:d839eae15f56 45 ".com/",
mbed_official 1:d839eae15f56 46 ".org/",
mbed_official 1:d839eae15f56 47 ".edu/",
mbed_official 1:d839eae15f56 48 ".net/",
mbed_official 1:d839eae15f56 49 ".info/",
mbed_official 1:d839eae15f56 50 ".biz/",
mbed_official 1:d839eae15f56 51 ".gov/",
mbed_official 1:d839eae15f56 52 ".com",
mbed_official 1:d839eae15f56 53 ".org",
mbed_official 1:d839eae15f56 54 ".edu",
mbed_official 1:d839eae15f56 55 ".net",
mbed_official 1:d839eae15f56 56 ".info",
mbed_official 1:d839eae15f56 57 ".biz",
mbed_official 1:d839eae15f56 58 ".gov"
mbed_official 1:d839eae15f56 59 };
mbed_official 1:d839eae15f56 60 const size_t NUM_SUFFIXES = sizeof(suffixes) / sizeof(char *);
mbed_official 1:d839eae15f56 61
mbed_official 1:d839eae15f56 62 size_t index = 0;
mbed_official 1:d839eae15f56 63
mbed_official 1:d839eae15f56 64 /* First byte is the URL Scheme. */
mbed_official 1:d839eae15f56 65 if (uriData[index] < NUM_PREFIXES) {
mbed_official 1:d839eae15f56 66 printf("%s", prefixes[uriData[index]]);
mbed_official 1:d839eae15f56 67 index++;
mbed_official 1:d839eae15f56 68 } else {
mbed_official 1:d839eae15f56 69 printf("URL Scheme was not encoded!");
mbed_official 1:d839eae15f56 70 return;
mbed_official 1:d839eae15f56 71 }
mbed_official 1:d839eae15f56 72
mbed_official 1:d839eae15f56 73 /* From second byte onwards we can have a character or a suffix */
mbed_official 1:d839eae15f56 74 while(index < uriLen) {
mbed_official 1:d839eae15f56 75 if (uriData[index] < NUM_SUFFIXES) {
mbed_official 1:d839eae15f56 76 printf("%s", suffixes[uriData[index]]);
mbed_official 1:d839eae15f56 77 } else {
mbed_official 1:d839eae15f56 78 printf("%c", uriData[index]);
mbed_official 1:d839eae15f56 79 }
mbed_official 1:d839eae15f56 80 index++;
mbed_official 1:d839eae15f56 81 }
mbed_official 1:d839eae15f56 82
mbed_official 1:d839eae15f56 83 printf("\n\r");
mbed_official 1:d839eae15f56 84 }
mbed_official 1:d839eae15f56 85
mbed_official 1:d839eae15f56 86 /*
mbed_official 1:d839eae15f56 87 * This function is called every time we scan an advertisement.
mbed_official 1:d839eae15f56 88 */
mbed_official 1:d839eae15f56 89 void advertisementCallback(const Gap::AdvertisementCallbackParams_t *params)
mbed_official 1:d839eae15f56 90 {
mbed_official 1:d839eae15f56 91 struct AdvertisingData_t {
mbed_official 1:d839eae15f56 92 uint8_t length; /* doesn't include itself */
mbed_official 1:d839eae15f56 93 GapAdvertisingData::DataType_t dataType;
mbed_official 1:d839eae15f56 94 uint8_t data[0];
mbed_official 1:d839eae15f56 95 } AdvDataPacket;
mbed_official 1:d839eae15f56 96
mbed_official 1:d839eae15f56 97 struct ApplicationData_t {
mbed_official 1:d839eae15f56 98 uint8_t applicationSpecificId[2];
mbed_official 1:d839eae15f56 99 uint8_t frameType;
mbed_official 1:d839eae15f56 100 uint8_t advPowerLevels;
mbed_official 1:d839eae15f56 101 uint8_t uriData[URI_MAX_LENGTH];
mbed_official 1:d839eae15f56 102 } AppDataPacket;
mbed_official 1:d839eae15f56 103
mbed_official 1:d839eae15f56 104 const uint8_t BEACON_UUID[sizeof(UUID::ShortUUIDBytes_t)] = {0xAA, 0xFE};
mbed_official 1:d839eae15f56 105 const uint8_t FRAME_TYPE_URL = 0x10;
mbed_official 1:d839eae15f56 106 const uint8_t APPLICATION_DATA_OFFSET = sizeof(ApplicationData_t) + sizeof(AdvDataPacket.dataType) - sizeof(AppDataPacket.uriData);
mbed_official 1:d839eae15f56 107
mbed_official 1:d839eae15f56 108 AdvertisingData_t *pAdvData;
mbed_official 1:d839eae15f56 109 size_t index = 0;
mbed_official 1:d839eae15f56 110 while(index < params->advertisingDataLen) {
mbed_official 1:d839eae15f56 111 pAdvData = (AdvertisingData_t *)&params->advertisingData[index];
mbed_official 1:d839eae15f56 112 if (pAdvData->dataType == GapAdvertisingData::SERVICE_DATA) {
mbed_official 1:d839eae15f56 113 ApplicationData_t *pAppData = (ApplicationData_t *) pAdvData->data;
mbed_official 1:d839eae15f56 114 if (!memcmp(pAppData->applicationSpecificId, BEACON_UUID, sizeof(BEACON_UUID)) && (pAppData->frameType == FRAME_TYPE_URL)) {
mbed_official 1:d839eae15f56 115 decodeURI(pAppData->uriData, pAdvData->length - APPLICATION_DATA_OFFSET);
mbed_official 1:d839eae15f56 116 break;
mbed_official 1:d839eae15f56 117 }
mbed_official 1:d839eae15f56 118 }
mbed_official 1:d839eae15f56 119 index += (pAdvData->length + 1);
mbed_official 1:d839eae15f56 120 }
mbed_official 1:d839eae15f56 121 }
mbed_official 1:d839eae15f56 122
mbed_official 1:d839eae15f56 123 void onBleInitError(BLE &ble, ble_error_t error)
mbed_official 1:d839eae15f56 124 {
mbed_official 1:d839eae15f56 125 /* Initialization error handling should go here */
mbed_official 1:d839eae15f56 126 }
mbed_official 1:d839eae15f56 127
mbed_official 1:d839eae15f56 128 void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
mbed_official 1:d839eae15f56 129 {
mbed_official 1:d839eae15f56 130 BLE& ble = params->ble;
mbed_official 1:d839eae15f56 131 ble_error_t error = params->error;
mbed_official 1:d839eae15f56 132
mbed_official 1:d839eae15f56 133 if (error != BLE_ERROR_NONE) {
mbed_official 1:d839eae15f56 134 onBleInitError(ble, error);
mbed_official 1:d839eae15f56 135 return;
mbed_official 1:d839eae15f56 136 }
mbed_official 1:d839eae15f56 137
mbed_official 1:d839eae15f56 138 if (ble.getInstanceID() != BLE::DEFAULT_INSTANCE) {
mbed_official 1:d839eae15f56 139 return;
mbed_official 1:d839eae15f56 140 }
mbed_official 1:d839eae15f56 141
mbed_official 1:d839eae15f56 142 ble.gap().setScanParams(1800 /* scan interval */, 1500 /* scan window */);
mbed_official 1:d839eae15f56 143 ble.gap().startScan(advertisementCallback);
mbed_official 1:d839eae15f56 144 }
mbed_official 1:d839eae15f56 145
mbed_official 1:d839eae15f56 146 void scheduleBleEventsProcessing(BLE::OnEventsToProcessCallbackContext* context) {
mbed_official 1:d839eae15f56 147 BLE &ble = BLE::Instance();
mbed_official 1:d839eae15f56 148 eventQueue.post(Callback<void()>(&ble, &BLE::processEvents));
mbed_official 1:d839eae15f56 149 }
mbed_official 1:d839eae15f56 150
mbed_official 1:d839eae15f56 151 int main()
mbed_official 1:d839eae15f56 152 {
mbed_official 1:d839eae15f56 153 eventQueue.post_every(500, periodicCallback);
mbed_official 1:d839eae15f56 154
mbed_official 1:d839eae15f56 155 BLE &ble = BLE::Instance();
mbed_official 1:d839eae15f56 156 ble.onEventsToProcess(scheduleBleEventsProcessing);
mbed_official 1:d839eae15f56 157 ble.init(bleInitComplete);
mbed_official 1:d839eae15f56 158
mbed_official 1:d839eae15f56 159 while (true) {
mbed_official 1:d839eae15f56 160 eventQueue.dispatch();
mbed_official 1:d839eae15f56 161 }
mbed_official 1:d839eae15f56 162
mbed_official 1:d839eae15f56 163 return 0;
mbed_official 1:d839eae15f56 164 }