Imagine you are at a sports store looking at a pair of Nike shoes. This store is really tech-savvy—they offer an iOS app to notify you of sales and specials, and you installed it before you went shopping.

When you walk up to a pair of shoes that catches your eye, your iPhone buzzes. The store's app pushed a notification with info on the display you're standing in front of. How did that happen? How did the app know you were looking at those specific shoes!? It's all thanks to beacons.

In this guide, we will learn about beacons and iBeacons, how they work, and how your Bean can act as an iBeacon.

What's a Beacon?

A beacon is a device equipped with Bluetooth Low Energy. It's always broadcasting data to any devices listening nearby. They take on a passive role: devices don't need to communicate with beacons to get data from them.

Differences Between Beacons and GPS Geolocation

In the shoe store example, the app on your iPhone was waiting for the store's beacon to come within range. Once the iPhone "hears" the store's beacon, it wakes up your app to perform a task. In this case, your app knows that you're near the shoe display, so it displays information on those shoes.

Before beacons, most smartphone apps used geographical region monitoring to add location awareness. Geographical region monitoring combines GPS and Wi-Fi data to determine a user's location, then notifies an app when the user enters or exits a region. This is also known as geofencing.

Unfortunately, GPS geolocation doesn't work well in many situations. For example, in shopping malls, smartphones often can't get GPS reception or accurately determine their location. In an art gallery, GPS doesn't provide high enough resolution to tell one exhibit apart from the one next to it. And most geofencing libraries are designed for static regions, not regions that change location from time to time.

Beacons triumph over geofencing in devices that:

  • Want to know when they're very close to a specific object
  • Need to work in places where GPS isn't available
  • Need better resolution than GPS provides
  • Interact with physical objects that change location from time to time

How Beacons Are Used

Beacons can be used in a variety of ways. We’ll go over some of the popular ways beacons are used.

Beacons can either be placed in a stationary spot next to a specific item, or on an object that moves from place to place. Here are some examples:

  • A hardware store could place a beacon at the end of each aisle and help users find items in nearby aisles.
  • An art gallery could place beacons at each exhibit, providing information on specific pieces when a user walks up to them.
  • A food discovery app can monitor for iBeacons located on food trucks that move around the city. When the user is near a food truck with a daily special, the app can tell the user about the special.

iBeacons solve many of the problems with geographical region monitoring. Devices determine their location by proximity to specific beacons, thus GPS location is not necessary for devices to discover iBeacons.

Advantage of Using iBeacons vs. Location-based Notifications

iBeacon is Apple’s proprietary version of the beacon concept. In the shoe store example above, the beacon we described is an iBeacon.

Apple limits what an iOS device is allowed to do when a user isn't directly using the device. If an app isn't running in the foreground, it must ask the OS to notify it when events occur by registering for a notification. That's the only way for an app to act on data when it's in the background or the device is locked.

In the past, iOS apps could only receive location-based notifications by registering for geographical region monitoring. This is a battery-intensive process for the iPhone. Phones performing geographical region monitoring need to track their location constantly with GPS and Wi-Fi triangulation.

In iOS 7, Apple added iBeacon support for iOS devices. This allowed apps to register for beacon region monitoring as well. Beacon region monitoring allows an app to be woken when they enter or exit the range of an iBeacon. iBeacons don’t rely on GPS location, which saves battery life. This helps developers build apps that know more about the world around them.

How does the Bean work with iBeacon?

The Bean can act as an iBeacon. The Bean library for Arduino provides commands to configure iBeacon parameters and turn iBeacon mode on and off.

Before You Begin

This tutorial assumes you have completed the Getting Started guide and that you understand how to upload a sketch to Bean using Bean Loader.



An iBeacon + Bean Example

In this example, we'll configure the Bean to act as an iBeacon. Then we'll show that it works by using an iOS app to monitor for iBeacons.

Program your Bean

Upload this sketch to your Bean:

void setup() {
  Bean.setBeaconParameters(0xDEAD, 0xBEEF, 0xCAFE);

void loop() {

Here's what the code does:

Line 2: Disable saving the Bean's BLE configuration to non-volatile memory.

Bean's LBM313 module stores its BLE configuration in non-volatile memory (NVRAM). NVRAM has a finite number of writes, and after it runs out of writes it's impossible to save new data. We disable saving to NVRAM so that we can preserve those cycles. And since we're configuring the BLE chip when the sketch starts, we don't need to save the advertising data to NVRAM anyway.

Line 3: Set the UUID, major, and minor values of the iBeacon.

iBeacons use 128-bit UUIDs, but Bean is limited to selecting 16 of those 128 bits:


In this example, we tell the Bean to use 0xDEAD in its UUID, so we'll see the following UUID on our iOS device:


The Core Location framework in iOS limits you to monitoring 20 regions at once. Regions are usually specified by a UUID. To differentiate between lots of devices, iBeacons have two 16-bit fields named "major" and "minor". These fields let you identify over 4 million different iBeacons that share the same UUID.

In this example, we tell the Bean to use the major ID 0xBEEF and the minor ID 0xCAFE.

Line 4: Tells the Bean to start advertising as an iBeacon with the configured values.

Line 8: Sleep for an arbitrary time. When we wake up, sleep again. The Arduino isn't used in this sketch, so it doesn't need to consume battery power by being awake.

Scan for Beacons with Node.js

If you're on OS X or Linux, we recommend you use Node.js to scan for nearby iBeacons. We've put together a simple script that scans for nearby iBeacons and prints their values as they're found.

  • Make sure your version of Node.js is up to date. Run node --version to check your installed version of Node.js. This script has been tested with v5.1.1 but might still work on older versions of Node.
  • If you don't already have Node.js installed, download the latest version from nodejs.org and install it.
  • Download the list-beacons script (view on GitHub) and extract it.
  • Open your terminal and navigate to the extracted directory list-beacons-master.
  • Run npm install to install its dependencies.
  • Finally, run node index.js to start the script.

After a few seconds, you should see iBeacon advertisements from your Bean start to appear. You'll also see iBeacon packets from any other iBeacons that may be near you:

List Beacons is running

The script tries to recognize Beans by matching against the bytes of the UUID common to all Beans. This isn't a reserved set of UUIDs, so other iBeacons might use a similar UUID and make this script think that they're Beans.

Scan for Beacons with Android

If you have an Android phone, you can use iBeacon and Eddystone Scanner by flurp laboratories to scan for nearby iBeacons. Download the app on the Play Store:

Once the app is installed, open it. At the main screen, tap the green circle to start scanning for iBeacons.

After a few seconds, you should see an iBeacon advertisement from your Bean appear. You'll also see iBeacon packets from any other iBeacons that may be near you:

Scanner main screen

The Eddystone app shows the iBeacon major and minor values as decimal, not hex. In this case, 48879 = 0xBEEF and 51966 = 0xCAFE.

Tap the row that shows your Bean's iBeacon packet to get more info:

Scanner main screen

Scan for Beacons with iOS

Scanning for iBeacons using iOS can be frustrating. Any iOS apps that scan for iBeacons are limited by what iOS allows them to do. To save power, iOS apps must explicitly subscribe to specific iBeacon UUIDs. In addition, iOS limits the number of UUIDs an app can subscribe to, so it's impossible to build an app to scan for all iBeacons.

We've put together a simple demo app that specifically searches for Beans with the iBeacon configuration DEAD + BEEF + CAFE. You'll need a free Apple Developer account, an OS X computer, and a physical iOS device to run this app.

Download our example app (view on GitHub) and extract it.

Open Bean iB Demo.xcodeproj in Xcode. Connect your iOS device via USB cable and press Cmd + R to build and run the app:

No beacons found

The screen will be blue and show Outside region if you're outside the region defined by your iBeacon. The screen will turn green and show Inside region once your iOS device detects the presence of your Bean's iBeacon:

One beacon found

Curious why the app is a little slow to pick up on iBeacons turning on and off and region enter/exit events? Check out our Learn More: The iOS Example App section below.


In this guide, you learned how iBeacons work, what they're good for, and why they're an interesting addition to the iOS ecosystem. You uploaded a sketch to Bean that made it act as an iBeacon. Finally, you verified your Bean was acting as an iBeacon by scanning for nearby iBeacons using Node.js, Android, or iOS.


Are you having trouble finding your iBeacon with Node.js, Android, or iOS? You may have to wait a few seconds for your device to detect iBeacon advertising packets.

If you've waited a while and no results appear, make sure your device has hardware support for Bluetooth Low Energy and that your OS is up to date.

  • If you're on Android, you need Android 4.3 or higher to use BLE.
  • The iPhone 4S and all iOS devices released after it support BLE.
  • If you're on a computer, make sure your Bluetooth chipset is supported by noble, the Node.js BLE library. You might need to use a Bluetooth USB dongle.

If none of those tips helped, try scanning for iBeacons using a different device.

Having trouble with this guide? Try the steps listed in General Bean troubleshooting. Or reach out to our community at Beantalk for direct help with your problem.

Learn More


Apple: iBeacon for Developers: Resources for developing an iOS app that supports iBeacon. Includes a great Getting Started guide.

Beacon Sandwich: What is iBeacon?: A great primer on iBeacon, common use cases, and the history of iBeacon.

AltBeacon: An alternate beacon protocol built by Radius Networks. AltBeacon is an open specification for beacons, with implementations for iOS and Android devices.

CLLocationManager Class Reference: Lots of important technical details for iOS developers building an app that uses iBeacon.

The iOS Example App

If you turn off your iBeacon, you might notice that the app doesn't immediately reflect the loss of your iBeacon's signal. You might also notice that it shows 0 iBeacons found for a while before transitioning from Inside region to Outside region.

Apple is secretive regarding the details, but at the time of this writing (in iOS 9.1) an iOS device waits 10 seconds before declaring an iBeacon has gone away and 30 seconds before declaring a region exit event. If your iBeacon disappears for 20 seconds, then appears again, iOS's 30-second timer will reset so that you have to wait 30 more seconds for a region exit event. This is to prevent a low-signal iBeacon from sending false region enter and exit events.

If you have more than one iBeacon with the same UUID, major, and minor value, your device will detect both of them. You can access more detail on detected iBeacons, such as RSSI and proximity, inside the locationManager:didRangeBeacons:inRegion method inside AppDelegate.swift.