Android Tutorial Discovering iBeacon devices with BLE2 library

This example uses the BLE2 library to continuously scan for BLE devices, looking for iBeacons.
It never connects to any device. It parses the advertising data and calculates the distance based on the RSSI level (it is pretty inaccurate).

The important code is in the Starter service module.
It starts scanning with the AllowDuplicates parameter set to true.

Whenever a device is found, the data is parsed and it raises a StateChanged event:

Sub Manager_DeviceFound (Name As String, Id As String, AdvertisingData As Map, RSSI As Double)
   Dim key As Int = -1 'type is important. Must be Int.
   If AdvertisingData.ContainsKey(key) Then
     Dim b() As Byte = AdvertisingData.Get(key)
     If b.Length > 4 And b(0) = 0x4c And b(1) = 0 And b(2) = 0x02 And b(3) = 0x15 Then
       Dim beacon As Beacon
       beacon.Initialize
       Dim raf As RandomAccessFile
       raf.Initialize3(b, False)
       Dim hex As String = bc.HexFromBytes(b)
       beacon.uuid = hex.SubString2(8, 40) 'bytes 4 - 19
       beacon.uniqueid = hex.SubString2(8, 48) 'this also includes the major and minor parts
       beacon.major = raf.ReadShort(20)
       beacon.minor = raf.ReadShort(22)
       Dim tx As Byte = raf.ReadSignedByte(24)
       beacon.distance = CalculateDistance(tx, RSSI)
       beacon.time = DateTime.Now
       beacons.Put(beacon.uniqueid, beacon)
       CallSub(Main, "StateChanged")
     End If
   End If
End Sub

In the Activity code, we go over the beacons and create or update CLV items.
Beacons that were not updated in the last 30 seconds are removed.

The example depends on ByteConverter library.

It is recommended to use the BeaconParser class instead of the code above: https://www.b4x.com/android/forum/t...iscover-ibeacons-and-eddystone-beacons.61127/

 

[Caronte]

...and calculates the distance based on the RSSI level (it is pretty inaccurate).

How inaccurate? Meters? Centimeters? Random distance?
Thanks!

 

[Erel]

See this discussion: https://www.quora.com/What-is-the-positioning-accuracy-of-iBeacon-and-other-BLE-technology

Meters + random. You can try to make it more stable by calculating a running average.

 

[bluedude]

I guess this could also easily be used for detecting the Eddystone Beacon format by Google?

 

[bluedude]

Would be nice if someone could extend the sample to: AltBeacons and Eddystone beacons. That way we could support everything with one piece of code.

 

[Erel]

I don't have here such a beacon however it shouldn't be complicated to use similar code to interact with any type of beacon. You just need to change the parsing code.

 

[bluedude]

I suck at hex etc. Here is the protocol format: https://github.com/google/eddystone/blob/master/protocol-specification.md

 

[Erel]

What is the output of the following code:

Dim bc As ByteConverter
For Each Key As Int In AdvertisingData.Keys
 Dim b() As Byte = AdvertisingData.Get(Key)
 Log($"Key: ${Key} = ${bc.HexFromBytes(b))}"$)
Next

 

[bluedude]

I will check. What is the $ symbol for BTW? Is that a new language feature?

 

[bluedude]

This is the result:

Key: 1 = 06
Key: 3 = AAFE
Key: 22 = 0DD068714579333125
Key: 9 = 5448494E47532E494F
Key: 10 = 04

 

[Erel]

I will check it. It seems that the structure is a bit more complex than iBeacon.

 

[bluedude]

Maybe, the most important part is the advertised URL and of course UUID etc.. Google's Beacons (Eddystone is their format) broadcasts an URL.

 

[Erel]

I've ordered such a beacon. Once it will arrive (several weeks probably) I will implement the parser.

 

[bluedude]

Kontak.io beacons can do both, iBeacon format and Eddystone. Great if you can implement it.

 

[Artigala]

Dear Support,
How to know, with BLE2 if BLE is supported (as previous version with "manager.BleSupported" ?
Thank you

 

[DonManfred]

as previous version with "manager.BleSupported" ?

If ble2 does not have such a method then you could use the old manager in addition... Check if supported with the manager and do the work with ble2 then

 

[Erel]

How to know, with BLE2 if BLE is supported (as previous version with "manager.BleSupported" ?

It is possible. However you are posting in the wrong place. Please start a new thread for this question.

 

[Licht2002]

Hi to all,

i test Erel`s Lib and Code.... with my BLE Beacon "MLE-15".... http://www.pboon.com/index.php?_m=mod_product&_a=view&p_id=223

** Activity (main) Resume **
Found: MLE-15, FF:FF:F0:00:17:1D, RSSI = -67, (MyMap) {1=[B@3ac46f1b, 2=[B@295fb8b8, 9=[B@1e59e691, 0=[B@35ad89f6}
Discovering services.
Connected

Is it normal, that i have to push the Button on MLE-15 to get an Connect?

Is this only with this Beacon.....???

Thx

Tom

 

[Erel]

This example doesn't connect. It only parses the advertising data.

 

[Licht2002]

Thx Erel,

which keyword to i have to search for...... is it possible to do such an autoconnect?

Thx
Tom