Bluetooth tethering on Edison (optional)

Your cell phone can act as a mobile “hotspot” to allow your rig to access the internet. This is an important part of keeping your rig looping, if you don’t have offline BG data setup, as you move around areas without known wifi networks.

A few things to know about using your phone’s hotspot feature:

  1. Hotspot is a feature of your phone AND cell phone provider. Please check with your cell phone provider and your service contract to confirm that hotspot feature is enabled and BT tethering is enabled.
  2. Hotspot, when activated, uses your cell phone’s data. Know what your cell phone plan data limits are and consider if you want to change/update based on your frequency of hotspot use. You can get an estimate of cell data use by resetting your cell data use, at the beginning of the day, within your phone.
  3. A device (like your rig) can be connected to your phone’s hotspot in one of three ways; wifi connection, BT tether, or USB plug:
  • wifi connection: You need to set up your wpa_supplicant list to include your hotspot information; network name and password. The wifi signal for the hotspot is not constantly broadcast by your phone, however. So when you want to use the wifi connection to your hotspot (for example, you are leaving your home wifi network and traveling), you will need to manually toggle your hotspot on so that the phone will broadcast a wifi signal for the rig to connect to. The other consideration is that since this is a wifi connection, the rig will not automatically disconnect when you come into one of your other known wifi networks. You will have to remember to manually disconnect (toggle hotspot off), if you do not wish to continue using cell data when you are home. Hotspot done by wifi connections also use more phone battery than a BT tether connection.
  • BT tether: BT tethering (also known as BT PAN Personal Area Network) requires your phone and rig to be BT-paired before they can connect (that’s what this section of the docs is specifically about). The advantage of connecting to your hotspot via BT tether is that it will happen automatically. You do not have to remember to toggle hotspot. Simply leave your hotspot toggled on as usual, leave the house, and within a few minutes (or sooner) your rig will BT tether to the hotspot. (Screenshot below shows what you’ll see in your network logs as you move from known wifi network to BT tether. Oref0-online will automatically find BT tether and connect.) Your rig will then use your cell phone as its internet connection. When your rig comes back into a known wifi network, it will automatically drop the BT tether and connect with the wifi network.
  • USB plug: You can plug devices into your cell phone to use hotspot. However, the phone would pull battery power from your rig and would drain your battery fairly quickly. This is not a recommended connection method for openaps use.

Pros and Cons (and usability) of Wifi Hotspot vs. BT Tethering Hotspot

  • If you choose wifi hotspot, you must manually turn it on; wait for the rig to connect; and when you get home, you must manually turn it off or your rig might not switch to your home wifi (depending on your settings in wpa_supplicant.conf). This option also consumes more battery on the phone.
  • If you choose to enable BT tethering, it takes more work to set it up, but it will automatically pick up when your rig loses wifi (i.e. walking out the door) without you even having to pull your phone out of your pocket; it automatically allows the rig to pick back up on wifi when it finds a known wifi network; and it consumes less battery on the phone compared to your wifi hotspot.

Bluetooth papertrail oref0 online switch

Phone selection for BT Tethering

  • Certain phones don’t work well using bluetooth tethering with OpenAPS. Various users have experimented, and the list below shows those that have been found to work okay, those that don’t and those with variable effectiveness. If you have something that is not on the list, please feel free to add it.
CellphoneWorks with Bluetooth Tethering?Issues/Experiences with BTUse with xDrip/xDripAPS and Dexcom G5
Google Pixel 2 with Android 8YesSupports tethering to both Wifi and Cellular network. No issues switching.
LG Nexus 5X with Android 7YesSupports tethering to both Wifi and Cellular network. No issues switching.Works well with Dexcom G5 and xDrip. No issues with compatibility. 90%+ capture rate.
Google Pixel with Android 7YesSupports tethering to both Wifi and Cellular network. No issues switching.Works well with Dexcom G5 and xDrip. No issues with compatibility. 90%+ capture rate.
Sony Xperia Z5 Compact with Android 7YesWorks with tethering for network access. It regularly disconnects from the rig (which doesn't seem to affect data flow) and roughly every 24-36 hours this results in complete loss of connectivity and requires a full reboot of the rig and the phone. Doesn't work well with phone swapping between Wifi and mobile - causes BT dropouts that require a reboot of the rig.No issues running xDrip/xDripAPS alongside the tethered connection. Achieves 90%+ packet collection from Dexcom G5.
Xiaomi Redmi 4 with MIUI 8 (Android 6)NoTethering can be set up, but it drops regularly requiring rig reboots. When phone switches between Wifi and cellular signal requires rig to be rebooted.Significant packet drops and data becomes almost unusable.
Xiaomi Redmi Note 4(X) -Snapdragon SoC version!!!YesTethering works in same time with Blukon(Nightrider) and SW3 connected. Also, read Notes for MIUI below*Excellent coverage.
Xiaomi Redmi 3 with MIUI 6 (Android 5)YesNo issues seen when tethered to cellular network. Doesn't allow tethering to wifi.Works fine with Dexcom G5 - 90% collection rate.
Samsung Galaxy S6 (Android 7)YesTethering to rig and cellular works okay. No data on swapping between cellular and wifi connections.Use with Dexcom G5 and rig not effective. Significant packet loss.
Samsung Galaxy JuniorYesPhone tethering switching between wifi and mobile not elegant and causes some issuesDifficulties found when using xDrip with the OpenAPS tethering. Packet loss occurs.
iPhoneYesUsers have experienced various levels of success with the iPhone bluetooth tethering and when the rig switches between wifi and BTNot Applicable. Experimental version of Loop to do something similar doesn't yet have feedback.
Acer PhoneNoMany data drops on the bluetooth connection for rig. Recommended to avoid.xDrip compatibility is poor - numerous drops throughout the day.
Samsumg Galaxy S7 Edge (G935F) Android 7.0YesExcellent BT tether using apps 'Bt AutoTether' and 'BT Tether'xDrip+ with G5 > 95% capture.
Samsung Galaxy A3 (2016) Android 6YesExcellent BT tether using app 'Blue Car Tethering'xDrip+ with G4, reliable capture using xDrip+ and using normal tether when running with Dexcom in G4-upload mode
Elephone P9000 Android 7YesSeems to work well, switching on/off BT tehethering as expected. Using 'Blue Car Tethering' with rig selected. Tested with phone screen off, works fine
Samsung Galaxy A5 (2017) Android 7.0YesExcellent BT tether, intermitent disconnecting when the area is flooded with other bluetooth devices. Use 'BT AutoTether' app along side to maintain connectionxDrip+ with G5, works really well with G5 transmitter directly, no compatibility issues and 95%+ consistent capture rate.

*Notes for MIUI users. MIUI kills processes in background to save battery. To get best results:

  • get Xiaomi with SD (Snapdragon) SoC. It works better than it’s MTK counterpart
  • install BTAutoTether
  • Settings–>Permissions–>Autostart (Turn it on for BTAutoTether)
  • Settings–>Permissions–>Other persmissions (Find BTAutoTether and make sure that all permissions are ticked for this app)
  • Hit Recents button (left button in bottom row of your phone) and find BTAutoTether, swipe it down and you’ll see Lock and Info icon. Press Lock icon

Configure Bluetooth tethering on Edison running Jubilinux [optional]

This section is completed by the install method found here . If you selected the option of installing Bluetooth at a later time during installation you may skip to Bluetooth Setup, the next section.

Install dependencies

You will need to get the MAC address from your phone or whatever device you are using.

  • On Android, go to Settings/About Phone/ Status; you will find your Bluetooth address looking like AA:BB:CC:DD:EE:FF
  • On iPhone, go to Settings/General/About; it will be under Bluetooth and will look like AA:BB:CC:DD:EE:FF

Now we need to re-run oref0-setup with the Bluetooth option, replacing AA:BB:CC:DD:EE:FF with what you found above. If you have the “To run again with these same options” command-line from the last time you ran oref0-setup, you can simply run that and append --btmac=AA:BB:CC:DD:EE:FF to the end. If not, you can run it interactively using:

cd && ~/src/oref0/bin/ --btmac=AA:BB:CC:DD:EE:FF

NOTE: Make sure the MAC address is in ALL CAPS.

Copy and paste the “To run again with these same options” command into your notes for the next time you need to run oref0-setup.

The first time running the script will take quite a bit longer as it is installing Bluez on your edison. The oref0-setup script may fail after installing Bluez. If so, just reboot your edison and run the setup command you copied to your notes.

You can confirm that Bluez has installed properly by using bluetoothd --version. If Bluez installed properly, a version number of 5.37 or greater will be returned. If it did not install properly, you will likely see 5.28. The procedures below will not work with the outdated version, so make sure you get version 5.37 or greater installed before continuing.

root@edisonhost:~# bluetoothd --version

Bluetooth setup

  • Stop cron to make sure oref0-online doesn’t interfere:

sudo service cron stop

  • Restart the Bluetooth daemon to start up the bluetooth services. (This is normally done automatically by oref0-online once everything is set up, but we want to do things manually this first time):

sudo killall bluetoothd

  • Wait a few seconds, and run it again, until you get bluetoothd: no process found returned. Then start it back up again:

sudo /usr/local/bin/bluetoothd --experimental &

As shown in the “success” section below, you should see a single line returned with a short string of numbers and then be returned to a clean prompt. If you instead see messages about D-bus Setup failed (as shown in the “Failure” part of screenshot), or otherwise see that you don’t have a clean prompt returned in order to enter the next command...go back to the sudo killall bluetoothd and try again. Bluetooth sudo commands

  • Wait at least 10 seconds, and then run:sudo hciconfig hci0 name $HOSTNAME
  • If you get a Can't change local name on hci0: Network is down (100) error, run bluetoothctl, then power off and power on, then exit and try sudo hciconfig hci0 name $HOSTNAME again.
  • Now launch the Bluetooth control program: bluetoothctl
  • and type each of the following:
power off

power on

discoverable on

scan on

agent on


Bluetooth pairing

For Android

The adapter is now discoverable for three minutes. Search for bluetooth devices on your phone and initiate pairing. The process varies depending on the phone and the dongle in use. The phone may provide a random PIN and bluetoothctl may ask you to confirm it. Enter ‘yes’. Then click ‘pair’ on the phone.

Remember you need to enable the sharing of your phones internet connection via Bluetooth go to Settings -> More –>Tethering & portable hotspot -> Bluetooth tethering [enable]

For iPhone

Your iPhone must be on the Settings/Bluetooth screen, and then you use the Edison to initiate pairing:


If successful, you will see on the Edison:

Request confirmation [agent] Confirm passkey 123456 (yes/no): yes

  • (WARNING: You must type in yes not just y to pair)
  • On your phone, tap the pair button that popped up.

Troubleshooting note: If after the pair AA:BB:CC:DD:EE:FF command you get a response of Failed to pair: org.bluez.Error.AlreadyExists, that means you likely have already tried to pair previously...but have run into problems getting it to run properly. Double-check that your cell provider allows for personal hotspots and bluetooth tethering. Make sure you have enabled those for your device. If you have confirmed those, you can remove AA:BB:CC:DD:EE:FF and start at the sudo commands again to attempt a fresh pairing.

  • Execute the paired-devices command to list the paired devices -

Your paired phone should be listed (in this example, a Samsung Galaxy S7):

Device AA:BB:CC:DD:EE:FF Samsung S7
  • Now trust the mobile device

    trust AA:BB:CC:DD:EE:FF

  • Quit bluetoothctl by typing quit and then enter.

Testing to make sure it works after you successfully did the above

  • Make sure your phone’s hotspot is enabled, but don’t let anything connect via wifi (you have to switch on the personal hotspot toggle, but then immediately back out of the personal hotspot screen before anything connects to your hotspot via wifi).

  • Now, try to establish a Bluetooth Network connection with your phone:

    sudo bt-pan client AA:BB:CC:DD:EE:FF

  • You should see an indicator on your phone (a blue bar on iPhone) that your Bluetooth network connection has established.

  • Next, to test your Internet connectivity, you’ll need to get an IP address:

    sudo dhclient bnep0

  • If that succeeds, you should be able to run ifconfig bnep0 and see something like:

bnep0     Link encap:Ethernet  HWaddr 98:4f:ee:03:a6:91
          inet addr:  Bcast:  Mask:

(for iPhone, the inet addr will always start with 172.20.10. - Android will likely be different)

  • To disconnect the connection, you can run:

    sudo bt-pan client -d AA:BB:CC:DD:EE:FF

  • Now, re-enable the cron service so oref0-online runs automatically every minute:

    sudo service cron start

  • Next, to test that Bluetooth starts up automatically, you can shut down your wifi for 2-3 minutes by running:

    iwconfig wlan0 txpower off; sleep 120; iwconfig wlan0 txpower auto

  • About 1 min later, your rig should connect to your phone with Bluetooth (blue bar will pop up on the iPhone). If it doesn’t, you should be able to wait 3 minutes and your terminal session should automatically reconnect. If that doesn’t connect, you’ll either need to reboot it or use a serial console connection to your Edison to troubleshoot further.

  • About a minute after wifi comes back on (terminal session restores), your Edison should automatically disconnect the Bluetooth connection.

Finally, it’s time to take a walk. About a minute after walking out of range of your home wifi, you should see that a device is connected to your phone via Bluetooth. Shortly after that you should see things update on Nightscout. About a minute after you come home, it should reconnect to wifi and automatically disconnect Bluetooth.

Additional App requirement on Android to enable automatic BT Tethering reconnects

On Android, the Bluetooth tether will shutdown if there is no tethering request within 3 minutes. Installing the application “BTAutoTethering” on your phone from the Play store will resolve this issue and allow the rig to switch to your phone when out of wifi range with no manual intervention.

This app has been used by numerous OpenAPS users, and found to work. It can be found here: Other Auto Tethering apps are available if you prefer something different.