Battery service (180F) not available

Not sure if this is a Linux/Chrome bug or related to #94. I’m running on Ubuntu 18.04 with Chrome. Heartrate test seems to work fine, so I’m confused why there are issues with Battery simulation.

I’m testing through this page: https://googlechrome.github.io/samples/web-bluetooth/battery-level.html Seeing the following “Live Output”:

Requesting Bluetooth Device...
Connecting to GATT Server...
Getting Battery Service...
Argh! NotFoundError: No Services matching UUID 0000180f-0000-1000-8000-00805f9b34fb found in Device.

I found that exact 0000180f-... battery_service UUID in the android code here: https://github.com/WebBluetoothCG/ble-test-peripheral-android/blob/277fbf7c586d579a9d270d71f7891144dea5e4d5/app/src/main/java/io/github/webbluetoothcg/bletestperipheral/BatteryServiceFragment.java#L45

The reset energy app works: https://googlechrome.github.io/samples/web-bluetooth/reset-energy.html

Live output of:

Requesting Bluetooth Device...
Connecting to GATT Server...
Getting Heart Rate Service...
Getting Heart Rate Control Point Characteristic...
Writing Heart Rate Control Point Characteristic...
> Energy expended has been reset.

Which successfully resets the energy expended value to zero in the android app.

Trying to troubleshoot with bluetoothctl (Linux CLI utility). Seeing reasonable GATT listing “Heart Rate Control Point” (2A39) when opening the heartrate tab in the android app:

menu gatt
list-attributes

Primary Service
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0001
	00001801-0000-1000-8000-00805f9b34fb
	Generic Attribute Profile
Characteristic
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0001/char0002
	00002a05-0000-1000-8000-00805f9b34fb
	Service Changed
Primary Service
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028
	0000180d-0000-1000-8000-00805f9b34fb
	Heart Rate
Characteristic
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028/char0029
	00002a37-0000-1000-8000-00805f9b34fb
	Heart Rate Measurement
Descriptor
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028/char0029/desc002b
	00002902-0000-1000-8000-00805f9b34fb
	Client Characteristic Configuration
Descriptor
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028/char0029/desc002c
	00002901-0000-1000-8000-00805f9b34fb
	Characteristic User Description
Characteristic
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028/char002d
	00002a38-0000-1000-8000-00805f9b34fb
	Body Sensor Location
Characteristic
	/org/bluez/hci0/dev_65_56_A7_7E_47_2C/service0028/char002f
	00002a39-0000-1000-8000-00805f9b34fb
	Heart Rate Control Point

But when switching over to the Battery tab, I don’t see the battery service listed.

menu gatt
list-attributes

Primary Service
	/org/bluez/hci0/dev_5C_91_FB_35_1C_CE/service0001
	00001801-0000-1000-8000-00805f9b34fb
	Generic Attribute Profile
Characteristic
	/org/bluez/hci0/dev_5C_91_FB_35_1C_CE/service0001/char0002
	00002a05-0000-1000-8000-00805f9b34fb
	Service Changed

Upon a fresh connection, I do see the 180F battery status UUID logged with the [CHG] tag, but it does not persist with list-attributes.

[miles g5]# connect 5C:91:FB:35:1C:CE
Attempting to connect to 5C:91:FB:35:1C:CE
[CHG] Device 5C:91:FB:35:1C:CE Connected: yes
Connection successful
[CHG] Device 54:59:49:F9:57:73 ServicesResolved: no
[CHG] Device 54:59:49:F9:57:73 Connected: no
[DEL] Characteristic
	/org/bluez/hci0/dev_54_59_49_F9_57_73/service0001/char0002
	00002a05-0000-1000-8000-00805f9b34fb
	Service Changed
[DEL] Primary Service
	/org/bluez/hci0/dev_54_59_49_F9_57_73/service0001
	00001801-0000-1000-8000-00805f9b34fb
	Generic Attribute Profile
[DEL] Device 54:59:49:F9:57:73 miles g5
[NEW] Primary Service
	/org/bluez/hci0/dev_5C_91_FB_35_1C_CE/service0001
	00001801-0000-1000-8000-00805f9b34fb
	Generic Attribute Profile
[NEW] Characteristic
	/org/bluez/hci0/dev_5C_91_FB_35_1C_CE/service0001/char0002
	00002a05-0000-1000-8000-00805f9b34fb
	Service Changed
[CHG] Device 5C:91:FB:35:1C:CE UUIDs: 00001800-0000-1000-8000-00805f9b34fb
[CHG] Device 5C:91:FB:35:1C:CE UUIDs: 00001801-0000-1000-8000-00805f9b34fb
[CHG] Device 5C:91:FB:35:1C:CE UUIDs: 0000180f-0000-1000-8000-00805f9b34fb
[CHG] Device 5C:91:FB:35:1C:CE ServicesResolved: yes

[dlech]

FWIW, sudo systemctl edit bluetooth.service with the following contents will probably work better for most people.

[Service]
ExecStart=
ExecStart=-/usr/lib/bluetooth/bluetoothd -P battery

If changes are made directly to /lib/systemd/system/bluetooth.service, they will be overwritten whenever the bluez package is updated.

[dlech]

It is not an “empty” command, it means delete all previous commands. Since the dbus type can only have one command, we have to delete the old one before we can add a new one. In the end there is still exactly one command.