May 2020 - Bluetooth-dev - lists.apple.com

Re: How to go about debugging interference with other bluetooth devices?
by Matthias Ringwald via Bluetooth-dev 20 May '20

20 May '20

site_archiver(a)lists.apple.com Delivered-To: Bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=bluekitchen-gmbh.com; s=default; h=To:In-Reply-To:Cc:References:Message-Id: Date:Subject:Mime-Version:From:Content-Transfer-Encoding:Content-Type:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=xExYtJ4nhDwB8W4QQ/2L8+mZGoSAFMzgTvSInT4j2kA=; b=wQMWPe2KM20qy3yyQMu3iih5BY uhtUqsJLtQ12QuCGUvFBX62baAVD7o1YDMJ8vBAPmBVByHALZj+EUcH56V4PHTs6SDH7LB0LoZ1oq cUWMDuBwGt/7izlYTjIfencxNilSTcZ4VZfPNUKihgU/vm4oZ//YDCM4MOCItBhqUbVoXEFvWyry+ t7tgNlj0MRmJJlu5QMiiMXaWTq7RAcZ9Tn/jiSOGjDNSTjFadamwtR2NQ7NKR5grXuF6ySBDyqAbY qUh2NwrwUAgZAwPm/k2ro1vYWQJ97PsDKtUqW+uBn/Cq+Fw5C8s1/d4ptdAyIw/URvEl9LXBMi/Wd 7FVB1K4A==; Hi Robert Using the PacketLogger might also be an option for end users - it just requires a Mac. The other obvious approach would be to use an expensive dual mode Bluetooth Sniffer. For single connections, you could use an open-source/free LE sniffer, but the interaction between multiple devices seems to be the problem on your end. Best, Matthias Sent from my iPhone > On 20 May 2020, at 12:24, Robert Atkins via Bluetooth-dev > <bluetooth-dev(a)lists.apple.com> wrote: > > > Hi all, > > Our app acts as both a central and a peripheral, continually scanning (in > both foreground and background) for our service UUID and connecting to > devices it finds. > > We've had reports our app is interfering with users' other devices (Apple > Watches, Fitbits and the like, and some blood glucose monitors and similar > devices.) How do we go about debugging this? One person on our team thought > his Garmin was acting up so we got him to do a sysdiagnose but there was > almost nothing relating to Bluetooth in the whole archive, and what was there > was not at all enlightening. After some dance resetting the watch and > restarting the phone the problem went away. > > I know about PacketLogger but if I understand correctly that doesn't help me > unless I have one of the malfunctioning devices in front of me. That's > difficult, in the current situation. > > Any tips? > > Thanks, Robert. > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/matthias%40bluekitche… > > This email sent to matthias(a)bluekitchen-gmbh.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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How to go about debugging interference with other bluetooth devices?
by Robert Atkins via Bluetooth-dev 20 May '20

20 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Hi all, Our app acts as both a central and a peripheral, continually scanning (in both foreground and background) for our service UUID and connecting to devices it finds. We've had reports our app is interfering with users' other devices (Apple Watches, Fitbits and the like, and some blood glucose monitors and similar devices.) How do we go about debugging this? One person on our team thought his Garmin was acting up so we got him to do a sysdiagnose but there was almost nothing relating to Bluetooth in the whole archive, and what was there was not at all enlightening. After some dance resetting the watch and restarting the phone the problem went away. I know about PacketLogger but if I understand correctly that doesn't help me unless I have one of the malfunctioning devices in front of me. That's difficult, in the current situation. Any tips? Thanks, Robert. _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: What causes a BLE device to appear in Settings/Bluetooth?
by Nick Brook via Bluetooth-dev 14 May '20

14 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nrbtech-io.20150623.gappssmtp.com; s=20150623; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=7JPzWrj9J40nfnB8uGTVKxpqmHGXvRRGbSH/CSoI+CQ=; b=tiFnjkX2gV3OmffAC/lZbkMYLT801LkEEdDJkcfGp51gRSd95u3TTYXqVsVf/O4Jc/ 9tYGRI3E+8aUUIlzTGcOy+aMBA6Xkg+tufiQ3V3qMTElk//JPZsRf7hQTUZWwCbPox+U xmJ7CO7qDEHrjhjOtabSyPNp7rqAtLpBDb6heJZqYUIlH6Fm7YWh01I036fFfObA4Lob qIowmXN5o3+8Enb7Bo2Y+jqie1+rQDtHYJD9Ojn9Gu+L4VirbF009B6MolTtqzdemSiV yekmLcLELLQK8bOCP4WtEdoGrBsHoTbUIgvOQYtV8xxt+GQ6b0ngkxFMt3KJYNiyqXH4 SNsw== If that device is connected by your App and remains connected when you go to iOS settings, it will show up in that list. I don’t think there is a way to avoid this. Thanks Nick W: https://nrbtech.io <https://nrbtech.io/> > On 14 May 2020, at 11:08, Robert Atkins <ratkins(a)pivotal.io> wrote: > > On Thu, 14 May 2020 at 09:41, Nick Brook <nick(a)nrbtech.io > <mailto:nick@nrbtech.io>> wrote: > iOS will not automatically connect to devices other than devices it is > already paired to, devices that apps connect to through CoreBluetooth, and > other iOS devices with the same Apple ID configured. > > So you're saying that all devices we connect to via CoreBluetooth and read a > characteristic value from will appear under "My Devices" in > Settings/Bluetooth? > > Is there any way to *prevent* this from happening? > > (Imagining a BTLE-based chat app like FireChat, there'd be an entry in "My > Devices" for every phone you exchanged data with, even if you weren't > communicating with that user directly but just passing on messages to them to > store-and-forward. This sounds less than ideal, you'll have a list of dozen's > of names like "Alice's iPhone", "Bob's iPhone" etc.) > > Cheers, Robert. _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: What causes a BLE device to appear in Settings/Bluetooth?
by Robert Atkins via Bluetooth-dev 14 May '20

14 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com On Thu, 14 May 2020 at 09:41, Nick Brook <nick(a)nrbtech.io> wrote: > iOS will not automatically connect to devices other than devices it is > already paired to, devices that apps connect to through CoreBluetooth, and > other iOS devices with the same Apple ID configured. > So you're saying that all devices we connect to via CoreBluetooth and read a characteristic value from will appear under "My Devices" in Settings/Bluetooth? Is there any way to *prevent* this from happening? (Imagining a BTLE-based chat app like FireChat, there'd be an entry in "My Devices" for every phone you exchanged data with, even if you weren't communicating with that user directly but just passing on messages to them to store-and-forward. This sounds less than ideal, you'll have a list of dozen's of names like "Alice's iPhone", "Bob's iPhone" etc.) Cheers, Robert. _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: What causes a BLE device to appear in Settings/Bluetooth?
by Nick Brook via Bluetooth-dev 14 May '20

14 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nrbtech-io.20150623.gappssmtp.com; s=20150623; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=sPXUH4iqFDc1NOHPj7xdy42BjjARqa+L4N5/yD2Dti0=; b=M1025Bi01VQ549t0WY198HvnCjAObeHGOEXcJ1wF8nvhED+Y68ISoZNoI+JxjwilDH WOz0WbqsYhL8s39NghdkvGiqD8tnF3NM+kQKK8Vr86nZfcIaMq7rluqHpeDzn4oRcQsQ 9s6RqUXAJ4BLI9BjZNMo6SK8wRY+Fc1gCseQlvpQQp60AsZ1zq6wpHmT8TXx3PzMl+zZ 3VbERk4Atv5WgFSAaF6Wr4D6mGVbs9JKfYH6fO6x2oypN6WI3p2u/wncva/+VviF+3d6 8ToGuZQYHKYbVP5b5naJUOIXnDL8yjnCoGj1VD+twNS6nHuqALQSLZJs6sB4ZTSxaW/u SP6Q== Hi Robert Devices will appear under ‘other devices’ if they are advertising a service that iOS natively supports, such as HID or audio. iOS will not automatically connect to devices other than devices it is already paired to, devices that apps connect to through CoreBluetooth, and other iOS devices with the same Apple ID configured. Adding characteristics which have encryption required means pairing will be required, so iOS devices that connect once and pair will automatically reconnect in future. Nick W: https://nrbtech.io > On 14 May 2020, at 08:03, Robert Atkins via Bluetooth-dev > <bluetooth-dev(a)lists.apple.com> wrote: > > >> On Thu, 14 May 2020 at 01:28, soan saini <soan09(a)yahoo.com> wrote: > >> In my observations, The devices which get paired starts showing up in >> settings. >> When they share keys after getting authenticated. >> >> If your peripheral has got some of the characteristics as secure, iOS will >> automatically start the authentication process and adds it to the bond table >> list. > > Hi Soan, and thanks for the response. > > What do you mean by "secure" characteristics? When we set up the > characteristics, we're not marking either of them as .readEncryptionRequired > or .writeEncryptionRequired: > > characteristic1 = CBMutableCharacteristic( > type: Environment.characteristic1UUID, > properties: CBCharacteristicProperties([.read, .notify]), > value: nil, > permissions: .readable) > > characteristic2 = CBMutableCharacteristic( > type: Environment.characteristic2UUID, > properties: CBCharacteristicProperties([.notify]), > value: nil, > permissions: .readable) > > Is the technical term for the list under Settings/Bluetooth the "bond table"? > That's helpful, I'll chase that up. > > Cheers, Robert. > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/nick%40nrbtech.io > > This email sent to nick(a)nrbtech.io _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: What causes a BLE device to appear in Settings/Bluetooth?
by Robert Atkins via Bluetooth-dev 14 May '20

14 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com On Thu, 14 May 2020 at 01:28, soan saini <soan09(a)yahoo.com> wrote: > In my observations, The devices which get paired starts showing up in > settings. > When they share keys after getting authenticated. > > If your peripheral has got some of the characteristics as secure, iOS will > automatically start the authentication process and adds it to the bond > table list. > Hi Soan, and thanks for the response. What do you mean by "secure" characteristics? When we set up the characteristics, we're not marking either of them as .readEncryptionRequired or .writeEncryptionRequired: characteristic1 = CBMutableCharacteristic( type: Environment.characteristic1UUID, properties: CBCharacteristicProperties([.read, .notify]), value: nil, permissions: .readable) characteristic2 = CBMutableCharacteristic( type: Environment.characteristic2UUID, properties: CBCharacteristicProperties([.notify]), value: nil, permissions: .readable) Is the technical term for the list under Settings/Bluetooth the "bond table"? That's helpful, I'll chase that up. Cheers, Robert. _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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What causes a BLE device to appear in Settings/Bluetooth?
by Robert Atkins via Bluetooth-dev 13 May '20

13 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Under what circumstances does a BLE device appear in the list under "Settings/Bluetooth" on a user's phone? Our app operates as both a central and a peripheral, and in some circumstances, peer devices we connect to appear in this list. Can anyone tell me what these circumstances are and if it's possible to prevent these entries from appearing? Thanks, Robert. _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: Background CoreBluetooth
by Nick Brook via Bluetooth-dev 07 May '20

07 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=tdsdEhxYCtuBklnAY5LmpXkMuik13pna9mv+RxZMt7A=; b=bRv1TBJ9ooxJxwqdgRhdQsWajopdbIB0kVxUfo2rwPH0ek+gE9602LOZODMUJBYv+W DfzijWsI7I9hefSLgNaizNUKzExeUsQ5R1vMN2CwFK3PgfL8Pu85xpTwWcMSpUOIKQqq rAff1GVUDqJpqn+AT0tfviVoa5Ic/WokDJLulE1XtsVTvLYMSBikDc7c4xJQ1XQ0/cHp 0jqhmn6r+rUw/BrKki1DcLHFoFj3OyZooZ8dhZPsEPsUBybJ+XKJKu/lZPHtfmnREd0s 3AkSjYJ7ZUjLJDtx1Th+qQzaAaVZHZYkbY6NfiV4Ebp06U1XbsQzDDC4CCDnkTAuxrEo GYFQ== If the app is quit or phone restarted I don’t think Android can wake up the App, the user has to open the app again. Another iOS device with the app in foreground wasn’t waking it up anyway. But I could be wrong! I think iOS will terminate the process eventually despite the keep alive pings. But then it may rediscover the other device in the background and reconnect again. As it is only happening every 8s it probably won’t hurt battery life too much, iOS is probably pretty good at managing the connection interval to keep power consumption as low as possible. I created a bug report for the Android issue as I think it could be fixed (https://github.com/nhsx/COVID-19-app-Android-BETA/issues/10) Nick W: https://nrbtech.io > On 8 May 2020, at 00:25, Darren Jones <djonesuk(a)me.com> wrote: > > Thanks for the write up. Your findings are pretty much the same as mine. > > I wonder how long the ‘keep alive’ can last. Possibly forever? > If you are in a household with multiple iOS users that install the app, an > initial connection could stay connected constantly while in range. I wonder > what effect that would have on battery life. > They’ve been very clever with the way Android can wake up iOS, so in a > crowded area with many devices there’s a good chance the app will work. > Walking to a local shop on your own and bumping into a few people, there’s a > good chance it won’t. > > > Sent from my iPhone > >>> On 8 May 2020, at 00:09, Nick Brook <nrbrook(a)gmail.com> wrote: >>> >> I’ve been playing around with this today, testing with my own code and >> looking at the NHS App. >> >> The NHS App is doing nothing special, as far as I can see >> It advertises a service, and in the background iOS puts the service in the >> “overflow” (one-hot encoded) >> Android looks for this specific one hot encoded value. Actually, it doesn’t >> look for a specific bit set, but a fixed set of bytes, so if other Apps are >> advertising services in the background on iOS the NHS App on Android might >> fail to discover it. This seems like a bug, although I’m not sure if they >> could work around it >> It attempts to keep connections (and the process) alive for as long as >> possible by sending “keep alive” data every 8s (under the 10s execution >> window apple provides) >> It is susceptible to the problems other Apps are (restarting the phone, >> quitting the app etc can break scanning and discovery) but it helps to >> overcome this through notifications to the user to reopen the app. >> I’m not sure if Apple imposes a time limit on scanning for/advertising >> services in the background although presumably there is a notification for >> this in the NHS App if it does. >> >> >> With the user notifications, if users actually respond to them it might work >> well enough to be effective. But I could see users ignoring the >> notifications if there are too many, and particular when out and about and >> busy these may get ignored. If they are ignored, the App may not work for a >> long period of time. >> >> It seems the UK government may be reconsidering the centralised approach now >> anyway: >> https://www.telegraph.co.uk/news/2020/05/06/nhs-explores-feasibility-moving… >> >> I’d be keen to hear any further insight into how the App is working or >> background bluetooth can made to work better. >> >> Nick Brook >> >> NRB Tech >> W: https://nrbtech.io >> >> >>> On 7 May 2020, at 21:17, Darren Jones via Bluetooth-dev >>> <bluetooth-dev(a)lists.apple.com> wrote: >>> >>> There is no location permission in the app. >>> Which is a good job as the questions over privacy would explode more than >>> they already have. >>> >>> Sent from my iPhone >>> >>>>> On 7 May 2020, at 21:14, Diego Alfarache <dalfarache(a)gmail.com> wrote: >>>>> >>>> >>>> These apps are going to have background location permission, which >>>> effectively gives them free reign to run almost anything in the >>>> background. >>>> >>>> I created a framework for a client that would act as both a peripheral and >>>> central while executing in the background, but only when they had “always” >>>> location permission. >>>> >>>> Diego >>>> >>>> >>>> >>>> From: "Jan Lübeck via Bluetooth-dev (Fyrastudio)" >>>> <bluetooth-dev(a)lists.apple.com> >>>> Reply-To: "Jan Lübeck (Fyrastudio)" <jan(a)fyrastudio.com> >>>> Date: Thursday, May 7, 2020 at 3:04 PM >>>> To: Darren Jones <djonesuk(a)me.com> >>>> Cc: <bluetooth-dev(a)lists.apple.com> >>>> Subject: Re: Background CoreBluetooth >>>> >>>> Apple did announce that they are sharing their APIs with specific >>>> developers. Maybe UK NHS is one of them? >>>> ______ >>>> Jan Lübeck >>>> Chief Technology Officer >>>> fyrastudio.com >>>> >>>> >>>> On Thu, May 7, 2020 at 3:48 PM Darren Jones via Bluetooth-dev >>>> <bluetooth-dev(a)lists.apple.com> wrote: >>>> Unless you have your head buried in the sand, I’m sure everyone has >>>> noticed the sagas going on with countries creating their own COVID-19 >>>> contact tracing apps. >>>> >>>> I have personally tried many times over the years to create an app that >>>> can broadcast and scan in the background to trigger a ‘contact trace’ and >>>> always failed. Yet the UK NHS are claiming they have an app that does just >>>> that. >>>> >>>> I’d love to hear from anyone that’s had experience with background BT. Is >>>> it possible? Can a background CBPeripheral be detected by a background >>>> CBCentral? >>>> >>>> If not, is there a definitive time period when discovery becomes >>>> impossible? >>>> >>>> Thanks >>>> _______________________________________________ >>>> Do not post admin requests to the list. They will be ignored. >>>> Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) >>>> Help/Unsubscribe/Update your Subscription: >>>> https://lists.apple.com/mailman/options/bluetooth-dev/jan%40fyrastudio.com >>>> >>>> This email sent to jan(a)fyrastudio.com >>>> _______________________________________________ Do not post admin requests >>>> to the list. They will be ignored. Bluetooth-dev mailing list >>>> (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: >>>> https://lists.apple.com/mailman/options/bluetooth-dev/dalfarache%40gmail.com >>>> This email sent to dalfarache(a)gmail.com >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> https://lists.apple.com/mailman/options/bluetooth-dev/nrbrook%40gmail.com >>> >>> This email sent to nrbrook(a)gmail.com >> _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: Background CoreBluetooth
by soan saini via Bluetooth-dev 07 May '20

07 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1588894683; bh=mxIncnxW1vKoyEa37uPBJ8GZdhe0RzA/YYDVBnIbEgw=; h=Date:From:To:Cc:In-Reply-To:References:Subject:From:Subject; b=IblzBz9EC4o8qx9OXx0fxnYwppLAUzjGtjwCSCAEYFlj9dqovnC8cMapGY4F2Bd/VlWBX7jeitrxJSucM9OrrhAJGfZYWqD07tl1uQ5m2cclznn594MHS0JGRQ6lQvQpn3FZcao7sPNuFC1U2oMN3+6MyZtuSlT1LnBSSckz8xfrdXWyFKaKhVOZ5HHdTEopnYbyXmplGEAB3OHDD7YiRW41rCLfZFLGMRFA/2+NZxQIt4134mAm/Ejm7doWt9JY2PGy5dUe4C765F2x8BWRJ/M/d41uI9FGx+iVUsZLPW7j+Vt4B1CZ8rYItMlMDRwAV7G1JJWHH49yw5bwowyenA== Hey, Thanks for Writeup, i am also trying to understand this process. If Apps are getting connected and not just reading Advertised Packets, To record close proximity with user. Will it cause issues like loosing disconnection with Headsets. As i understand there is a limit on how many simultaneous connections can be made from phone. On Friday, 8 May 2020, 09:25:25 GMT+10, Darren Jones via Bluetooth-dev <bluetooth-dev(a)lists.apple.com> wrote: Thanks for the write up. Your findings are pretty much the same as mine. I wonder how long the ‘keep alive’ can last. Possibly forever?If you are in a household with multiple iOS users that install the app, an initial connection could stay connected constantly while in range. I wonder what effect that would have on battery life.They’ve been very clever with the way Android can wake up iOS, so in a crowded area with many devices there’s a good chance the app will work.Walking to a local shop on your own and bumping into a few people, there’s a good chance it won’t. Sent from my iPhone On 8 May 2020, at 00:09, Nick Brook <nrbrook(a)gmail.com> wrote: I’ve been playing around with this today, testing with my own code and looking at the NHS App. - The NHS App is doing nothing special, as far as I can see - It advertises a service, and in the background iOS puts the service in the “overflow” (one-hot encoded) - Android looks for this specific one hot encoded value. Actually, it doesn’t look for a specific bit set, but a fixed set of bytes, so if other Apps are advertising services in the background on iOS the NHS App on Android might fail to discover it. This seems like a bug, although I’m not sure if they could work around it - It attempts to keep connections (and the process) alive for as long as possible by sending “keep alive” data every 8s (under the 10s execution window apple provides) - It is susceptible to the problems other Apps are (restarting the phone, quitting the app etc can break scanning and discovery) but it helps to overcome this through notifications to the user to reopen the app. - I’m not sure if Apple imposes a time limit on scanning for/advertising services in the background although presumably there is a notification for this in the NHS App if it does. With the user notifications, if users actually respond to them it might work well enough to be effective. But I could see users ignoring the notifications if there are too many, and particular when out and about and busy these may get ignored. If they are ignored, the App may not work for a long period of time. It seems the UK government may be reconsidering the centralised approach now anyway: https://www.telegraph.co.uk/news/2020/05/06/nhs-explores-feasibility-moving… I’d be keen to hear any further insight into how the App is working or background bluetooth can made to work better. Nick Brook NRB TechW: https://nrbtech.io On 7 May 2020, at 21:17, Darren Jones via Bluetooth-dev <bluetooth-dev(a)lists.apple.com> wrote: There is no location permission in the app.Which is a good job as the questions over privacy would explode more than they already have. Sent from my iPhone On 7 May 2020, at 21:14, Diego Alfarache <dalfarache(a)gmail.com> wrote: These apps are going to have background location permission, which effectively gives them free reign to run almost anything in the background. I created a framework for a client that would act as both a peripheral and central while executing in the background, but only when they had “always” location permission. Diego From: "Jan Lübeck via Bluetooth-dev (Fyrastudio)" <bluetooth-dev(a)lists.apple.com> Reply-To: "Jan Lübeck (Fyrastudio)" <jan(a)fyrastudio.com> Date: Thursday, May 7, 2020 at 3:04 PM To: Darren Jones <djonesuk(a)me.com> Cc: <bluetooth-dev(a)lists.apple.com> Subject: Re: Background CoreBluetooth Apple did announce that they are sharing their APIs with specific developers. Maybe UK NHS is one of them? ______Jan LübeckChief Technology Officerfyrastudio.com On Thu, May 7, 2020 at 3:48 PM Darren Jones via Bluetooth-dev <bluetooth-dev(a)lists.apple.com> wrote: Unless you have your head buried in the sand, I’m sure everyone has noticed the sagas going on with countries creating their own COVID-19 contact tracing apps. I have personally tried many times over the years to create an app that can broadcast and scan in the background to trigger a ‘contact trace’ and always failed. Yet the UK NHS are claiming they have an app that does just that. I’d love to hear from anyone that’s had experience with background BT. Is it possible? Can a background CBPeripheral be detected by a background CBCentral? If not, is there a definitive time period when discovery becomes impossible? Thanks _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/jan%40fyrastudio.com This email sent to jan(a)fyrastudio.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/dalfarache%40gmail.com This email sent to dalfarache(a)gmail.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/nrbrook%40gmail.com This email sent to nrbrook(a)gmail.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/soan09%40yahoo.com This email sent to soan09(a)yahoo.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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Re: Background CoreBluetooth
by Roland King via Bluetooth-dev 07 May '20

07 May '20

site_archiver(a)lists.apple.com Delivered-To: bluetooth-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha1; c=relaxed; d=rols.org; h=content-type :content-transfer-encoding:from:mime-version:subject:date :message-id:references:cc:in-reply-to:to; s=rols.org; bh=rHJ3R7S 5zhvEh2GoCs1RqQvCHH0=; b=nG6zn2DYJz4WMBjYrD9UGL4EyTK4Fq043mm48I2 lclYoD0vZINADQD7a4BBH4j0bp364cTJFz9PikaiqWi4Dh5Hmy/SIXWjON4aQp4B ctN0Fo3kdOfmpHmTjYLCqEv5dfNw4KqmfUNFfi/FZLjuAZH/CTbB2tYSKrF4Xxwm vP2E= No I don’t think it is possible. Eg the Singapore version of this “Trace Together” suffers from the same problem and the notes say if you’re using it on an iPhone please keep it as the active app and the phone as awake as much as you can. This makes it pretty useless. You can read the developer comments on the app in the App Store in reply to some negative reviews or here https://tracetogether.zendesk.com/hc/en-sg/articles/360044846854-Does-Trace… I fully expect the NHS and I hope the team in Singapore which built “trace together” to move to the Apple/Google API when available as this will work consistently across platforms in the background like all other system level Bluetooth communications do. > On 8 May 2020, at 03:48, Darren Jones via Bluetooth-dev > <bluetooth-dev(a)lists.apple.com> wrote: > > Unless you have your head buried in the sand, I’m sure everyone has noticed > the sagas going on with countries creating their own COVID-19 contact tracing > apps. > > I have personally tried many times over the years to create an app that can > broadcast and scan in the background to trigger a ‘contact trace’ and always > failed. Yet the UK NHS are claiming they have an app that does just that. > > I’d love to hear from anyone that’s had experience with background BT. Is it > possible? Can a background CBPeripheral be detected by a background CBCentral? > > If not, is there a definitive time period when discovery becomes impossible? > > Thanks > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/rols%40rols.org > > This email sent to rols(a)rols.org _______________________________________________ Do not post admin requests to the list. They will be ignored. Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/bluetooth-dev/site_archiver%40lists… This email sent to site_archiver(a)lists.apple.com

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