BTLE For Linux, Raspberry PI

Raspberry PI BTLE C++ Library

BUNGET

beta-version_plus

####### (Bunget, read 'ge' as in George)

Build lib bunget and demo application

Prerequisites

Linux
- sudo apt-get install uuid-dev
- sudo apt-get install cmake
- sudo apt-get install build-essential
- sudo apt-get install libcrypto++-dev

Description:

BUNGET is a C++ library for Linux which help to write GAP/GATT servers (Bluetooth 4.0). It provides abstract classes and methods to create GATT services, characteristics (READ/WRITE/NOTIFICATIONS). The library does not require the Bluez, but it requires some bluetooth utilities. The library was written from scratch. The idea of writing 'yet another BTLE implemetation' came after I spend days and days trying Bluez and Bleno. I could not get Blues working programatically and easy. Bleno is terible slow and tremendous resource eater, also brings entire java enciclopedia along with. So: here is a simple C++ library which uses just a HCI socket and GAP/GATT protocol helping to write GATT services.

Server only: GATT services characteristics, descriptors or beacons.
Characteristics: R W I N + Descriptors.
Requires: hciconfig tool from blues package in /usr/bin
(iii). Bunget lib will stop the bluetooth service.
(iiii) Read all documents.
Latest version is at: https://github.com/zirexix

(iii) Before running bunget

Disable / uninstall bluetooth service.
Disable kill any bt managers if you have a desktop environment.
check if there are any processes keeping BT up. (ps ax | grep blu )
Kill them all. Make sure they not restart.

Usage

Turn device running Linux system in to a GATT server.
- Soon all specific dev platforms for embedded custom chips will be replaced by Linux, pretty soon...
Debug HCI clients

Block Diagram:

Demo video. If the image does not work use this link: http://209.177.145.195/share/bunget.mov

Credits:

Bluez, Bleno, StCube/BlueNrg, Bluetooth 4.0 Specs.

##License: Free, for non commercial products, otherwise you need a written personalised license from the Author.

SDK:

See libbunget.h in the source tree
See main.cpp in the source tree

For services use 16 bit UUID's. Maximum 8 servics / 8 characteristics.
Do not mix UUIDS of 16 bytes with UUIDS of 128 bytes on the same running unit.
The GATT (services/charact./descr.) was tested only with 16 byte UUIDS.
Beacon advertising, needs 128 bit UUID's only.

Demo R-PI console (left). ArduUiPush APK Right

ArduUiPush;No screens scanned and loaded for advertised name.

Check also: ArduUiPush demo: https://www.youtube.com/watch?v=Fw4yCe2ejNw

Class Diagram

Issues Tweaks

On different BTLE dongles the timing between receiving HCI event and sending back data disrupts the functionality.
- Build with DEBUG enabled. If after connection the progress stops around this TRACE:

HCI: ACL_START -->[16]0240200B0007000400100100FFFF0028 GATT DATA:ATT_OP_READ_BY_GROUP_REQ
my_proc event: onServicesDiscovered

* Tweak the receive<delay>send value at main line 127. . 
* My Broadcom dongle works with >16 ms delay on R-PI and with >2 ms on 4 quad HP Intel PC.

```javascript
     IServer*    BS =  ctx->new_server(&procedure, dev, "advname", 0/* tweak delay*/);

Descriptors for data type not suppotred yet. Use GATT registerred UUIDS or know your type on both ends.

Code excerpt

#include <fstream>
#include <iostream>
#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <assert.h>
#include <uuid.h>
#include <libbunget.h>

using namespace std;
using namespace bunget;


#define UID_GPIO    0x3400
#define UID_TIME    0x3401
#define UID_TEMP    0x3403

bool __alive = true;
class my_proc : public ISrvProc
{
public:
    my_proc();
    void onServicesDiscovered(std::vector<IHandler*>& els); // called when remote discover services
    void onReadRequest(IHandler* pc);                       // called when remote reads pc's value charact.
    int evSubscribesNotify(IHandler* pc, bool b);           // called when remote writes notification descriptor !=0
    void onIndicate(IHandler* pc);                          // called when remote wants pc's indicator value
    void onWriteRequest(IHandler* pc);                      // called when remote writes pc charateristic
    void onWriteDescriptor(IHandler* pc, IHandler* pd);     // called when remote writes pc's charact descriptor pd
    void evAdvertise(bool onoff);                           // called when advertising turns on/off
    void evDeviceState(bool onoff);                         //called when device dongle is plugged / unplugged (buggy still)
    void evClientState(bool connected);                     // called when a client connects / disconnetcs 
    bool evLoop(IServer* ps);                               //called when the hci-socket idles. Be short!. 
                                                            // return false to break the run() blocking call.    

private:
    void        _prepare_gpio17();  // RPI specific, to control LEDS for the purpose of the demo
    const char* _get_time();        // reads local time, and returns a string
    float       _get_temp();        // reads temp,  on RPI. 
    const char* _get_temp_s();      // same as above but returns a string
    uint8_t     _get_gpio();        // reads GPIO status on RPI
    void        _send_value(IHandler* pc);  // sends a value to GATT

public:
    char        _some[20];
    bool        _subscribed;
    IHandler*   LedChr;       // RW
    IHandler*   TimeChr;      // NIR
    IHandler*   Temp1Chr;     // NIR
};



int main(int n, char* v[])
{
    BtCtx*      ctx = BtCtx::instance();        // get singleton Bunget instance
    my_proc     procedure;                      // callback  instance of above class

    IServer*    BS =  ctx->new_server(&procedure, 0, "rpi-bunget", 0);      // one GATT server per hci device
    IService*   ps = BS->add_service(0x123F,"demo");                        // add a service to the GATT server
    
    //
    // add some characterisitcs
    //
    procedure.LedChr = ps->add_charact(UID_GPIO,PROPERTY_WRITE|PROPERTY_INDICATE|PROPERTY_NOTIFY,
                             0,
                             FORMAT_RAW, 1); // 1 / 0  // many per service

    procedure.TimeChr = ps->add_charact(UID_TIME, PROPERTY_READ|PROPERTY_NOTIFY,
                             0,
                             FORMAT_RAW, 20); // we send it as string

    procedure.Temp1Chr = ps->add_charact(UID_TEMP, PROPERTY_NOTIFY|PROPERTY_INDICATE,
                              0,
                              FORMAT_RAW, 20); // we send it as string 

    try{
        BS->advertise(true);
        BS->run();
    }
    catch(hexecption& ex)
    {
        TRACE(ex.report());
    }
    return 0;
}

my_proc::my_proc()
{
    _subscribed=false;
    _prepare_gpio17();
}

bool my_proc::evLoop(IServer* ps)
{
    static int inawhile=0;

    // notification
    if(_subscribed && inawhile++%600==0)
    {
        _send_value(TimeChr);
        _send_value(Temp1Chr);
    }
    return true;
}

//  ... see main.cpp for the rest of the callback implenentation

####################################################################### #######################################################################

H O W TO B U I L D

#######################################################################

cmake .
make
cd bin
sudo ./bunget 0  (hci device number)

#########################################################################

Raspberry PI Build (check compiler version )

The C compiler identification is GNU 4.9.2
Board: RPI-2
Fresh distribution: Linux minibian 4.1.18-v7+ #846 SMP Thu Feb 25 14:22:53 GMT 2016 armv7l GNU/Linux
Login as root/raspberry

#
# Prerequisites. Also required for new system
#
apt-get update
apt-get install bluez # (needed for hciconfig utility for now)
apt-get install cmake
apt-get install  g++
apt-get install  rfkill
apt-get install libcrypto++-dev
service bluetooth stop   # not mandatory
update-rc.d -f  bluetooth remove   # not mandatory


git clone https://github.com/comarius/bunget
cd bunget
cmake .
make
cd bin

#
# check if the device is detected
#
root@minibian:~/bunget/src/bin# hciconfig
hci0:	Type: BR/EDR  Bus: USB
	BD Address: 5C:F3:70:76:B2:B2  ACL MTU: 1021:8  SCO MTU: 64:1
	DOWN 
	RX bytes:616 acl:0 sco:0 events:34 errors:0
	TX bytes:380 acl:0 sco:0 commands:34 errors:0

# argument for hci0 is 0, for hci1 is 1 and so on
# therefore we run our GATT server as

./bunget 0


root@minibian:~/bunget/src/bin# ./bunget 0
sh: echo: I/O error
Failed to stop bluetoothd.service: Unit bluetoothd.service not loaded.
my_proc event:  onAdvertized:0 
my_proc event:  onDeviceStatus:1 
my_proc event:  onAdvertized:1 
#
# here I connected the BTLE scanner phone and read all the characteristics
#
accepted: 5F:C9:32:F3:5D:F6,* 
my_proc event: onServicesDiscovered 
my_proc event:  onWriteDescriptor:1 
my_proc event: onSubscribesNotify:3400=1 
my_proc event:  onWriteDescriptor:1 
my_proc event: onSubscribesNotify:3401=1 
my_proc event:  onWriteDescriptor:1 
my_proc event: onSubscribesNotify:3403=1

Issues

stop bunget
disable bluetooth service
stop bluetooth service
kill any process which uses bluetooth (scripts, desktop daemons, etc.)
restart on the mobile the bluetooth service (off 5 seconds, then on / reboot recomanded on some chipsets)
Tweak the timout [0-64] in main ctx->new_server(&procedure, dev, hostname, );

Tested on

Make sure any processes that uses BT is killed, otherwise the LE disconects, or fails to grab services.

C H I P

On board BT4 and default installed system. See the C H I P readme page.

R-PI 3

Linux minibian 4.4.17-v7+ #901 SMP Fri Aug 12 17:57:27 BST 2016 armv7l GNU/Linux
gcc (Raspbian 4.9.2-10) 4.9.2
g++ (Raspbian 4.9.2-10) 4.9.2

Ubuntu 16.04

Linux X540LA (ACER) 4.4.0-47-generic #68-Ubuntu SMP Wed Oct 26 19:39:52 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
gcc (Ubuntu 4.8.5-4ubuntu2) 4.8.5
g++ (Ubuntu 4.8.5-4ubuntu2) 4.8.5

Linux Mint

Linux hp 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
g++ (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4

Dongle USB used

[33544.074470] usb 4-1.2: new full-speed USB device number 5 using ehci-pci
[33544.171100] usb 4-1.2: New USB device found, idVendor=0a5c, idProduct=21e8
[33544.171108] usb 4-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[33544.171114] usb 4-1.2: Product: BCM20702A0
[33544.171118] usb 4-1.2: Manufacturer: Broadcom Corp
[33544.171123] usb 4-1.2: SerialNumber: 5CF3706B72D6
[33544.172183] bluetooth hci1: Direct firmware load for brcm/BCM20702A0-0a5c-21e8.hcd failed with error -2
[33544.172193] Bluetooth: hci1: BCM: patch brcm/BCM20702A0-0a5c-21e8.hcd not found

Device Used

Nexux Tablet Android 6.0,
ACER T06, Android 6.0, using following apps
- BLE Scanner
- ArduiuiPush
Failed with ACER AI - 830
Failed with Android 4.4.2