Bluetoothctl or gatttool for BLE notifications from multiple devices - bluetooth

Question

I have read many questions on the topic but found no information on how to best (or if it is even possible) to receive notifications from more than 1 device at a time using any library or API (preferably command line or Python library).
After connecting to different devices e.g. Heart Rate monitor and Phone, or two HR monitors, is there a way to receive data from 1 service from each device at the same time?
EDIT:
I have managed to connect different devices of the same characteristics and been able to get notifications from them using Bluetoothctl (part of Bluez) so long as I don't request the same service, which answers my question partially; still, does anyone know of a better way to do this?

Answer 1

1) First of all there is a github python project that does just that in Linux on Raspberry Pi: https://github.com/IanHarvey/bluepy
2) Second this snipet from Anthony Chiu uses that API to communicate with multiple devices using notifications:
from bluepy.btle import Scanner, DefaultDelegate, Peripheral
import threading
class NotificationDelegate(DefaultDelegate):
def __init__(self, number):
DefaultDelegate.__init__(self)
self.number = number
def handleNotification(self, cHandle, data):
print 'Notification:\nConnection:'+str(self.number)+ \nHandler:'+str(cHandle)+'\nMsg:'+data
bt_addrs = ['00:15:83:00:45:98', '00:15:83:00:86:72']
connections = []
connection_threads = []
scanner = Scanner(0)
class ConnectionHandlerThread (threading.Thread):
def __init__(self, connection_index):
threading.Thread.__init__(self)
self.connection_index = connection_index
def run(self):
connection = connections[self.connection_index]
connection.setDelegate(NotificationDelegate(self.connection_index))
while True:
if connection.waitForNotifications(1):
connection.writeCharacteristic(37, 'Thank you for the notification!')
while True:
print'Connected: '+str(len(connection_threads))
print 'Scanning...'
devices = scanner.scan(2)
for d in devices:
print(d.addr)
if d.addr in bt_addrs:
p = Peripheral(d)
connections.append(p)
t = ConnectionHandlerThread(len(connections)-1)
t.start()
connection_threads.append(t)
3) I will just write the manual connection option with bluetoothctl that you probably tried. Since it wasn't listed here, I will add that too:
**Manual connection with bluetoothctl: ** To get the list of characteristics you can use the “list-attributes” command after establing connection and entering Generic Attribute Submenu through menu gatt in bluetoothctl, which should print the same list as above:
list-attributes 00:61:61:15:8D:60
To read an attribute you first select it, with the -you guessed it- “select-attribute” command:
select-attribute /org/bluez/hci0/dev_00_61_61_15_8D_60/service000a/char000b
After that you can issue the “read” command, without any parameters.
To read a characteristic continuously (if characteristic supports it) , use the “notify” command:
notify on
PS: This is my first answer on stackoverflow :)
I am also new to BLE, so bear with me. Am interested in your project, any links / contact are appreciated :)
You can find me on alexandrudancu.com