I don't have any trouble getting reads off the device with the supplied Android app. As I mentioned these connection troubles seem to be ubiquitous with BlueZ. This particular device initiates a read through an Android app, so it seems logical that I would need to send it something in order to initiate a read, although I'm not entirely sure how I would figure out what that something is. I've tried to do reads off of push-button devices but those appear to be even more reliable (at least this device connects somewhat reliably -- the others crap out even earlier). On Thu, Jan 2, 2020 at 8:20 PM Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> wrote: > > Hi Peter, > > On Thu, Jan 2, 2020 at 6:10 PM Peter Belau <pbelau1@xxxxxxxxx> wrote: > > > > hci trace doesn't give me much of anything although I'd be happy to > > attach the trace. Which 'spec' should I check here? > > https://www.bluetooth.org/docman/handlers/DownloadDoc.ashx?doc_id=243126 > > It doesn't look like there is anything required to subscribe but > perhaps it is disconnecting because there is no measurement in > progress or you have to set the time via CTS. > > > On Thu, Jan 2, 2020 at 8:04 PM Luiz Augusto von Dentz > > <luiz.dentz@xxxxxxxxx> wrote: > > > > > > Hi Peter, > > > > > > On Thu, Jan 2, 2020 at 5:58 PM Peter Belau <pbelau1@xxxxxxxxx> wrote: > > > > > > > > Thank you very much for the response; I did not realize that > > > > 'indicate' was exclusive to doing an attribute read. However, "notify > > > > on" doesn't seem to help. The device disconnects after a read and now > > > > I can no longer connect to it at all: > > > > > > > > QardioARM:/service0400/char0410]# notify on > > > > Notify started > > > > [CHG] Device 5C:D6:1F:0E:0A:7D ServicesResolved: no > > > > [CHG] Device 5C:D6:1F:0E:0A:7D Connected: no > > > > > > > > [bluetooth]# connect 5C:D6:1F:0E:0A:7D > > > > > > > > > > > > Attempting to connect to 5C:D6:1F:0E:0A:7D > > > > Failed to connect: org.bluez.Error.Failed > > > > > > > > > > > > On the bluetoothd side I'm seeing: > > > > > > > > bluetoothd[20426]: src/agent.c:agent_disconnect() Agent :1.626 disconnected > > > > bluetoothd[20426]: src/agent.c:remove_default_agent() Default agent cleared > > > > bluetoothd[20426]: src/adapter.c:set_mode() sending set mode command for index 0 > > > > bluetoothd[20426]: src/agent.c:agent_destroy() agent :1.626 > > > > bluetoothd[20426]: src/agent.c:agent_unref() 0x55e718787df0: ref=0 > > > > bluetoothd[20426]: src/adapter.c:new_settings_callback() Settings: 0x00000a01 > > > > bluetoothd[20426]: src/adapter.c:settings_changed() Changed settings: 0x00000010 > > > > bluetoothd[20426]: src/adapter.c:settings_changed() Pending settings: 0x00000000 > > > > bluetoothd[20426]: src/agent.c:add_default_agent() Default agent set > > > > to :1.627 /org/bluez/agent > > > > bluetoothd[20426]: src/adapter.c:set_mode() sending set mode command for index 0 > > > > bluetoothd[20426]: src/agent.c:agent_ref() 0x55e7187b7a00: ref=1 > > > > bluetoothd[20426]: src/agent.c:register_agent() agent :1.627 > > > > bluetoothd[20426]: src/adapter.c:new_settings_callback() Settings: 0x00000a11 > > > > bluetoothd[20426]: src/adapter.c:settings_changed() Changed settings: 0x00000010 > > > > bluetoothd[20426]: src/adapter.c:settings_changed() Pending settings: 0x00000000 > > > > bluetoothd[20426]: src/device.c:att_connect_cb() connect error: > > > > Connection refused (111) > > > > > > > > I should note that I've tried a number of BTLE blood pressure devices > > > > with a variety of BT controllers and Bluez cannot seem to maintain > > > > reliable connections with any of the configurations I've tried. Any > > > > help would be much appreciated. > > > > > > HCI trace would probably help here, you can collect it using btmon. > > > Have you check the spec if there are other steps before subscribing? > > > > > > > On Thu, Jan 2, 2020 at 7:30 PM Luiz Augusto von Dentz > > > > <luiz.dentz@xxxxxxxxx> wrote: > > > > > > > > > > Hi Peter, > > > > > > > > > > On Thu, Jan 2, 2020 at 5:22 PM Peter Belau <pbelau1@xxxxxxxxx> wrote: > > > > > > > > > > > > I'm trying to get a Qardio ARM BP monitor working with Linux/Bluez but > > > > > > cannot seem to read any device characteristics with Bluez. My > > > > > > interaction through bluetoothctl looks like this: > > > > > > > > > > > > # menu gatt > > > > > > # attribute-info 00002a35-0000-1000-8000-00805f9b34fb > > > > > > Characteristic - Blood Pressure Measurement > > > > > > UUID: 00002a35-0000-1000-8000-00805f9b34fb > > > > > > Service: /org/bluez/hci0/dev_B0_49_5F_02_B5_61/service0400 > > > > > > Value: > > > > > > 16 7f 00 49 00 5b 00 00 00 00 00 00 00 00 35 00 ...I.[........5. > > > > > > 00 00 .. > > > > > > Notifying: no > > > > > > Flags: indicate > > > > > > # select-attribute 00002a35-0000-1000-8000-00805f9b34fb > > > > > > # read > > > > > > # Attempting to read /org/bluez/hci0/dev_B0_49_5F_02_B5_61/service0400/char0410 > > > > > > Failed to read: org.bluez.Error.Failed > > > > > > > > > > > > I have bluetoothd running with debug flags but nothing appears in the > > > > > > debug logs. What am I doing wrong? > > > > > > > > > > Look at the flags, it only has indicate so it doesn't support reading directly. > > > > > > > > > > -- > > > > > Luiz Augusto von Dentz > > > > > > > > > > > > -- > > > Luiz Augusto von Dentz > > > > -- > Luiz Augusto von Dentz
