Unable to read battery level from battery characteristic on Thingy:52 using bluetoothctl on linux

[emotive]

Below is the output from a 'bluetoothctl' session for one of my thingy:52's 

This is running on a raspberry pi 4 using Ubuntu Mate 20.xx

The output below is using command line 'bluetoothctl'. (Clearly the actual Mac adrs you see has been altered for this post)

The Thingy can be connected to and all characteristics can be read ( those identified as 'Read' in the spec)

Using 'bluetoothctl: notify on' for other notification capable characteristics will produce updates. 

Regarding reading the battery level/value, the nRF Connect app for iOS can read the battery level. 

The bluetoothctl session below shows that I can connect to the thingy:52, drill into the battery characteristic, set it to notify, 

but no notification is received. This is even after sufficient time has elapsed for the battery state to change. 

Yes, I am aware that the documentation shows no battery notification is sent unless the state of the battery (read that as level of charge) changes. 

However, the iOS nRFConnect app is able to do a one-shot read of the battery level/value if one taps on the 'single down arrow' icon.

The FW version 2.2.0 (which is running on my Thingy:52) shows the battery level type to be both Read/Notify. 

I would not argue since the iOS app allows a single-shot read. 

From the 'bluetoothctl' session below, the service '000a' and char '000b' is the battery service as found by the 'bluetoothctl' command

[bluetooth]# list-attributes xx:18:81:32:yy:B0 

// I identified this as the Battery Service, the 0001801 was my clue.

[NEW] Primary Service (Handle 0xb000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a
00001801-0000-1000-8000-00805f9b34fb
Generic Attribute Profile
[NEW] Characteristic (Handle 0xd6b0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b
00002a05-0000-1000-8000-00805f9b34fb
Service Changed
[NEW] Descriptor (Handle 0x4680)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b/desc000d
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration

Can anyone tell me what is needed in order to do at least a one shot read of the battery value? 

Note if I do a ' read' I do get an error, the same error as when I try to read a notification only attribute. 

Any help is appreciated... 

Regards... 

Bluetoothctl session begin:

[bluetooth]# connect xx:18:81:32:yy:B0

[Thingy2]# menu gatt

[Thingy2]# select-attribute /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b

[Thingy2:/service000a/char000b]# attribute-info /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b

Characteristic - Service Changed

UUID: 00002a05-0000-1000-8000-00805f9b34fb

Service: /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a

Notifying: no //<---

Flags: indicate

[Thingy2:/service000a/char000b]# notify on

[CHG] Attribute /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b Notifying: yes

Notify started //<---

[Thingy2:/service000a/char000b]# attribute-info /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b

Characteristic - Service Changed

UUID: 00002a05-0000-1000-8000-00805f9b34fb

Service: /org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a

Notifying: yes //<---

Flags: indicate

[Thingy2:/service000a/char000b]# 

[Hung Bui]

Hi Emotive, 

Are you sure 0x1801 is battery service ? 
Battery service is defined as 0x180F here.

And you can find the battery level characteristic (0x2A19) listed here.

0x1801 is the GAP service , that include the service changed characteristic you may have mistakenly enabled. 

I would also suggest to capture a sniffer trace in addition to the log just to double check if the communication was correct. 

[emotive]

Thank you for your quick response. Yes 0x180F is the battery service. When I execute a [bluetoothctl]# list as below, I do see the battery service. Is the battery service a gatt service? 

After bluetoothctl establishes a connection, it lists all the available gatt services. That 'process' assigns the path to the characteristic so one can then use the attribute-select and list-attribute commands. (I am sure you already know all this)

So, I still do not know how to read the value of the battery service using bluetoothctl since no path to the characteristic is shown even when going into the gatt submenu of bluetoothctl and executing a list-attributes on the device Thingy:52 as shown below (sorry for the whole 250 line dump, I thought it might be useful to see the actual output)

Unfortunately I do not have a DK to use a sniffer on? 

I can see the battery value under this bus command after running the following:

sudo dbus-send --print-reply=literal --system --dest=org.bluez /org/bluez/hci0/dev_xx_18_81_32_yy_B0 org.freedesktop.DBus.Properties.GetAll string:"org.bluez.Battery1"

   array [

      dict entry(

         Percentage         variant             byte 98

      )

   ]

Below is a complete dump and even though the service is listed under info, it is not listed in the gatt service menu, as in there is no path to the service/char as there is for the other services and their characteristics.

So you have any idea how to read the value of the battery using bluetoothctl? 

I see no way to list the gatt 'path' to the battery service. 

[Thingy2]# info
Device xx:18:81:32:yy:B0 (random)
Name: Thingy2
Alias: Thingy2
Paired: no
Trusted: no
Blocked: no
Connected: yes
LegacyPairing: no
UUID: Generic Access Profile (00001800-0000-1000-8000-00805f9b34fb)
UUID: Generic Attribute Profile (00001801-0000-1000-8000-00805f9b34fb)
UUID: Battery Service (0000180f-0000-1000-8000-00805f9b34fb)
UUID: Nordic Semiconductor ASA (0000fe59-0000-1000-8000-00805f9b34fb)
UUID: Vendor specific (ef680100-9b35-4933-9b10-52ffa9740042)
UUID: Vendor specific (ef680200-9b35-4933-9b10-52ffa9740042)
UUID: Vendor specific (ef680300-9b35-4933-9b10-52ffa9740042)
UUID: Vendor specific (ef680400-9b35-4933-9b10-52ffa9740042)
UUID: Vendor specific (ef680500-9b35-4933-9b10-52ffa9740042)

[Thingy2]# menu gatt

[Thingy2]# list-attributes xx_18:81:32:yy:B0

Primary Service (Handle 0xfbd4)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a
00001801-0000-1000-8000-00805f9b34fb
Generic Attribute Profile
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b
00002a05-0000-1000-8000-00805f9b34fb
Service Changed
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000a/char000b/desc000d
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e
ef680100-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char000f
ef680101-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char0011
ef680102-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char0013
ef680104-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char0015
ef680105-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char0017
ef680106-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char0019
ef680107-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char001b
ef680108-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service000e/char001d
ef680109-9b35-4933-9b10-52ffa9740042
Vendor specific
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f
ef680200-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0020
ef680201-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0020/desc0022
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x5230)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0023
ef680202-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0023/desc0025
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x6b90)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0026
ef680203-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0026/desc0028
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x7b50)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0029
ef680204-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char0029/desc002b
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x9a90)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char002c
ef680205-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char002c/desc002e
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0xaa30)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service001f/char002f
ef680206-9b35-4933-9b10-52ffa9740042
Vendor specific
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031
ef680400-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0032
ef680401-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0034
ef680402-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0034/desc0036
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0xd180)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0037
ef680403-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0037/desc0039
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0xdf80)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char003a
ef680404-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char003a/desc003c
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0xed10)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char003d
ef680405-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char003d/desc003f
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x0170)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0040
ef680406-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0040/desc0042
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x0f20)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0043
ef680407-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0043/desc0045
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x23c0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0046
ef680408-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0046/desc0048
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x3c10)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0049
ef680409-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char0049/desc004b
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x49c0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char004c
ef68040a-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0031/char004c/desc004e
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service004f
ef680300-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service004f/char0050
ef680302-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service004f/char0050/desc0052
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x5ec0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service004f/char0053
ef680301-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x5ec0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service004f/char0055
ef680303-9b35-4933-9b10-52ffa9740042
Vendor specific
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057
ef680500-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char0058
ef680501-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char005a
ef680502-9b35-4933-9b10-52ffa9740042
Vendor specific
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char005c
ef680503-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char005c/desc005e
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Characteristic (Handle 0x9af0)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char005f
ef680504-9b35-4933-9b10-52ffa9740042
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0057/char005f/desc0061
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration
Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066
0000fe59-0000-1000-8000-00805f9b34fb
Nordic Semiconductor ASA
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066/char0067
8ec90003-f315-4f60-9fb8-838830daea50
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066/char0067/desc0069
00002902-0000-1000-8000-00805f9b34fb
Client Characteristic Configuration

[Hung Bui]

Hi, 

I'm afraid that I'm not very familiar with Bluez, so I don't know how I can help you. 
You may want to post your question at other forum/portal that more specifically to BlueZ stack. 

My suggestion for you is to try to test on one of our example so that the attribute table is smaller and easier to handle than go straight to the Thingy52. 

The battery service is not under GAP  or GATT service. It's a Bluetooth SIG standard service. 

[emotive]

With utmost respect for your knowledge, 'bluetoothctl' under linux is 'the' current standard. It is implemented through Bluez. So one purpose in providing the commands I used (which are basically 4) is so that you or anyone in your group could run the same test on any Ubuntu Linux based system (Current ver 20.xx Ubuntu Mate on Rasberry Pi 4). I would guess that you all have multiple linux based systems for development and test.

Since this is not something you are familiar with (and again I say this with respect for your position and knowledge), perhaps another engineer could quickly verify whether the service is or is not accessible under bluetoothctl and or bluez?

Since the other service 1801 is accessible, I do not yet see an explanation as to why 180F would not also be accessible as well?

I have even read posts that state that the standard bluetooth daemon loads a plugin which blocks the 'battery service'? And running systemctl with the correct args can stop this plugin from being loaded. (-P battery or --property --value=battery) as in

systemctl daemon-reload

systemctl start bluetooth --property --value=battery

Well, I tried all that and still no joy.

Since the Battery service is not under GAP or GATT, but a standard Bluetooth SIG service...

Can anyone reading this or in your group determine why or how one reads the battery level using the service 180F and the attribute 2A19 by implementing command line bluetoothctl or bluez?

Thank you.

[Hung Bui]

As I mentioned, I'm not very familiar with Linux environment. I will try to forward your question to some one that has more experience with Linux here. 

But as I mentioned, please try to test with a simple application first before you go straight to the thingy application. 

In my case, when checking with nrf Connect app, the battery service is located right above 0000fe59-0000-1000-8000-00805f9b34fb DFU service. 

Please note again, regarding question on 3rd party platform, please try to ask on other support channels in addition to posting the question here, as we don't have any control over how bluetoothctl works.

I did a quick search and in this doc, the battery service is discovered in the example and you have a path to access it: 

https://core.docs.ubuntu.com/en/stacks/bluetooth/bluez/docs/reference/gatt-services

[emotive]

Thank you again for the quick response.

The link you provided is one that I have used.(At least the command order)

If there is a specific memory offset from 0000fe59-... would you let me know what the offset is?

Or, is it necessary to pair with the thingy in order to even see the battery service?

I have connected to the thingy many times with

[bluetoothctl]# connect <mac adrs here>

Each time as included above, I get a list of services with their tiered characteristics and descriptions (partially included here)

Primary Service (Handle 0xacdc)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066
0000fe59-0000-1000-8000-00805f9b34fb
Nordic Semiconductor ASA
Characteristic (Handle 0x0240)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066/char0067
8ec90003-f315-4f60-9fb8-838830daea50
Vendor specific
Descriptor (Handle 0x0000)
/org/bluez/hci0/dev_xx_18_81_32_yy_B0/service0066/char0067/desc0069
00002902-0000-1000-8000-00805f9b34fb

...

However, the one that is never shown is the battery service.

Using the [bluetoothctl]# list (after having connected to the thingy, not paired)

I get a list which includes the UUID for the battery service as shown above and repeated here for clarity:

...

UUID: Generic Access Profile (00001800-0000-1000-8000-00805f9b34fb)
UUID: Generic Attribute Profile (00001801-0000-1000-8000-00805f9b34fb)
UUID: Battery Service (0000180f-0000-1000-8000-00805f9b34fb)  // <------

...

The Bluetooth spec lists the battery service as type GSS. 

However, on completion of the above 'connect' command under bluetoothctl, the device/service/characteristic path is not found and does not exist for the battery service.

This says that the battery service is not enumerated under bluetoothctl?

So, are there specific offsets from the 0000fe59 location that I missed in the documentation?

The benefit (supposed) to using bluetoothctl is that it is 'standardized' with Bluez under linux.

This means that much of the software stack that would have to be handwritten/cut-pasted/ etc is already done and optimized for the linux kernel.

There are older tools which have bee deprecated hcitool and gatttool and those were rolled into bluetoothctl.

If anyone in your group has insights as to how to get at this ever-elusive battery service under bluetoothctl please let me know.

Thank you again...