Slides from a Trifork Mobile lunch talk about iBeacons on Android on 5/5-2014.

1. Trifork iBeacon Demo
Mobile Lunch 05.05.2014

2. Bluetooth Low Energy (BLE)

3. iBeacons
• iBeacon is a BLE profile
specification formalised by
Apple. It is not a standard.
• It can work on all devices
that support Bluetooth LE,
not just iOS.
• 2 primary use cases:
Proximity and Ranging.
• Works indoors.

4. What is iBeacons

5. Bluetooth LE Support
• Requires a Bluetooth LE chip. Only newer phones/
tablets has it.
• Windows: Phone 8.1 (?%), Lumia 520, 620, 625,
720
• iOS: 7.0+ (87%), iPhone 4s+, iPad 3rd generation+
• Android: 4.3 (14%), Samsung Galaxy S3+, Nexus
4+

6. iBeacon protocol
• Advertisement bluetooth
package.
• Mac-address is spoofed on
iOS.
• Proximity UUID: 16 byte UUID
• Major: 0 - 65.535
• Minor: 0 - 65.535
• TxPower: Signal Strength at
1m from iBeacon.

7. Detecting a iBeacon
• Can make drive-by-detection hard. Battery matters on both
ends.
• Devices do not talk to each other. Phone simply listens to
heartbeats from iBeacon.
• Scan time and intervals should be non-regular numbers,
eg. scan period of 1.1s. instead of 1s.

8. Detecting proximity
• Just check for existence of the
right combination of
<Proximity UUID, Major,
Minor>
• No guarantee that iBeacon is
unique.

9. Detecting range
• Hard problem. Many scientific papers
on the subject.
• Water blocks bluetooth signals. Guess
what humans are mostly made of?
• Algorithm not known on iOS.
• Thus only rough estimates ->
Immediate, Near, Far.
• Recommendation is to use relative
range instead of absolute.
• “You know if you are close to an
iBeacon, otherwise you don’t know
anything”.

10. Code/SDK’s
• Android doesn’t not provide a common API. Each
app must implement it.
• Androids Geofencing API doesn’t support
iBeacons (yet).
• SDK’s exist that make it easy: Estimote, Radius
Network, Gimbal (soon?).
• Demo app: https://github.com/cmelchior/trifork-
ibeacon-demo

11. Keynote now has animated GIF Support :)

12. Lessons learned
• Android Bluetooth stack is flawed. Crashes when it has
seen 2000 MAC’s: https://code.google.com/p/android/
issues/detail?id=67272
• When monitoring, battery impact is small. It is still
noticeable over a day however. Scan intervals
matters!!!
• Ranging is very unprecise.
• Exit/Entry into a region can happen very frequently due
to scans missing the iBeacon.

13. Links
• http://en.wikipedia.org/wiki/IBeacon
• http://www.warski.org/blog/2014/01/how-ibeacons-work/
• http://stackoverflow.com/questions/18906988/what-is-the-ibeacon-
bluetooth-profile
• http://stackoverflow.com/questions/20416218/understanding-
ibeacon-distancing
• http://localz.co/blog/ibeacon-ble-hardware-commercial-comparison/
• https://github.com/RadiusNetworks/android-ibeacon-service
• https://github.com/Estimote/Android-SDK