I'm trying to connect my rpi0 w to any android device via Bluetooth LE(low energy) , i can pair but i can't connect them ,an error always showed (Connection failed,No usable services on this device ) on vnc and (Failed to connect:org.bluez.Error.Failed) in terminal , i tried with stretch and Jessie version but no connection!i followed the tutorial of adafruit with the new version of bluez 5.50 [https://www.youtube.com/watch?v=5fQR2PHMDWE] but i found the same problem , please help !
Connect my RpiZW to Android device through BLE，Bluez 5.5
Can pair but can't connect them,
Error "Connection failed, No usable services" on VNC,
Error “Failed to connect:org.bluez.Error.Failed) in terminal
I tried to pair the following BlueTooth headphone with Rpi4B buster and found a similar problem: can pair but cannot connect.
I use the following to test three Bluetooth speakers:
SamSung Galazy C9 Pro
Acer Aspire Intel Core i5 Win 10 PC with USB Bluetooth dongle, Bluetooth Driver Intel 14/11/2016 19.30.1646.851
Rpi4B Raspbian 10 buster 2019jul10 version, preinstalled bluez utitilies
I tested the following three Bluetooth speakers:
Creative MUVO 2,
SamSung Galazy C9 Pro all three Bluetooth speaker paired easily and smoothly.
Acer Aspire WinPC Intel Bluetooth river can pair MUVO2, Rapoo A500, but never Mi NDZ03GB
Rpi4B onboard Bluetooth can only pair and connect Creative MUVO2 paired and connected smoothly. Can pair other two, but cannot connect.
Easy and Stable Pairing Tricks
Reboot Rpi4B every time before trying to pair/connect.
Uncomment the following two line in file "/etc/bluetooth/main.conf" the following two lines to disable timeouts:
DiscoverableTimeout = 0
PairableTimeout = 0
Rpi4B on board Bluetooth is weak comparing to SamSung smart phone and WinPC with Bluetooth dongle.
Next step is to try to use an USB Bluetooth adapter dongle to see if it improves Rpi4B's Bluetooh pairing/connecting performance.
Rpi4B Raspbian 10 buster and three BlueTooth Speaker Evaluation Notes
Some months ago I tried to pair/connect a couple of Bluetooth devices with my Rpi3B+ and found everything disappointing: difficult/unreliable/intermittent failing to discover/pair/connect the BT devices. I googled and found no useful help around. So I gave up, waiting for Rpi4B to come along. I also bought two more Bluetooth speakers to try.
Now the time has come for me to try again. I first tried to pair the three speakers with my Samsung smart phone and everything went well, implying both BT speakers are working OK.
I then tried the following with all three speakers, Creative, XiaoMi, Rapoo. The procedure is:
(a) reboot Rpi4B (important to get repeatable/reliable results),
(b) GUI Deskop top right hand corner BT icon to discover/pair the speaker,
(c) when paired, click the speaker icon (beside WiFi icon) to check "connection" and adjusting volume,
(d) play a mp3 file using VLC media player. I found that I can always pair and "connect" (VLC to connect to speaker) with the Creative BT speaker. But for the XiaoMi and Rapoo BT speakers, I can always "pair", but never "connect" (system error message is "cannot use "default"speaker, or speaker icon always red crossed)
So my conclusion is that Rpi4B BT works reliably with my Creative speaker but not XiaoMi or Rapoo. Creative speaker costs twice of the other two, so I think its power is perhaps also twice bigger or sensitive. Anyway, I tried to do more evaluation, I found I could no longer detect nor pair, not to mention connect. I guessed the Rpi4 chips must had been heated up and became crazy. So I waited for 20 minutes or and and also added heat sinks to the chips. Then everything comes back normal again. My second quick and dirty conclusion is that Rpi4B, if heated up, might go crazy!
So for now I am only using the Creative Bluetooth speaker which I found very stable and reliable. Every time I want to use my VLC media player to play music, I do the following:
(1) Reboot Rpi4B Raspbian 10 Buster Jul 10,
(2) Pair speaker (clicking BlueTooth icon),
(3) Connect speaker and adjust volume (clicking speaker icon),
(4) Use VLC to play music. The pairing is smooth, almost detected /pairing smoothly first time, very stable, no disconnecting/dispairing for the 2 hours testing.
I once thought about using an USB BT dongle to replace on board weak BT guy, but too lazy to do it now. :)
Installing BlueTooth, BlueZ, and FTP packages for Raspbian stretch 9
I first installed the bluetooh and ftp packages for testing.
Testing Android Smart Phone Samsung Galaxy C9 Pro App to connect to Rpi3B+ using Bluetooth
I then tried the Android apps ftp server/client and send files (Bluetooth File Transfer), but found both not working. Error message is something like no ftp blue services, ...
I guess there is some incompatability problem with stretch 9 and the androd app. I need to try again later.
I once found it OK to connect Rpi to Bluetooh serial modules HC05/HC05, and also HC05/HC06 to android phone and found everything OK communicating using text (serial 9600N81). So I think I better try again with BLE HC10, to see if I missed anything important. Then I will come back to try Rpi direct bluetooth to android again.
/ to continue, ...
Operating voltage: 1.9 - 3.6 V
Communication distance: 100 meters
Bluetooth 4.0, 2.4 GHZ, GFSK, 8db, 80 metres
(8) Developer Study Guide: Deploying BlueZ v5.50 on Raspberry Pi Board
(9) Bluetooth Mesh Models Technical Overview