January 2013 - Bluetooth-dev

Re: Central and Peripheral at the same time?
by Andras Kovi 11 Jan '13

11 Jan '13

Some points you may need to consider: - (as Etan also stated) slow scan in background - not all advertisement data is sent in backgrounded mode from peripheral (at least this is my experience) - duplicate filtering is always true for backgrounded scanning (you will have to restart the scan to sense returning devices) There may be other issues but this is what comes into my mind at the moment. Regards, Andras On 2013.01.11., at 17:14, Darren Jones <djonesuk(a)me.com> wrote: > Thank you. I want to use non pairing so CoreBluetooth is the way. > I'm glad it's possible. I wasn't sure if background scanning and advertising would be allowed. > > > On 11 Jan 2013, at 16:02, Etan Kissling <kissling(a)oberon.ch> wrote: > >> Darren, >> >> If you want to perform iPhone to iPhone communication only, I suggest using GameKit for it. >> You will have an increased throughput, as classic Bluetooth is used as a transport, and don't have >> to worry about specifying who is master and who is slave. >> >> If you want to stay with CoreBluetooth: at least from the Bluetooth Core Specification, a device is >> allowed to scan and advertise at the same time. I have not yet tried it under iOS, but can tell for your >> background requirement that scanning times are pretty slow while backgrounded (around 55x >> advertisement interval). Also don't forget to stop scanning and advertising as soon as you establish >> a connection. >> >> Etan >> >> >> On 10.01.2013, at 23:59, Darren Jones <djonesuk(a)me.com> wrote: >> >>> Is it possible to use CBCentral scanning and CBPeripheral advertising at the same time? (Also in the background) >>> >>> If I wanted 2 random iPhones to communicate and both where set to Central or both to Peripheral they wouldn't see each other. I'd like to remove that they would both have to know which method to activate. >>> >>> Is that possible? >>> >>> Thanks >>> >>> Sent from my iPhone 5 >>> _______________________________________________ >>> 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/kissling%40oberon.ch >>> >>> This email sent to kissling(a)oberon.ch >> > > _______________________________________________ > 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/allprog%40gmail.com > > This email sent to allprog(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: Central and Peripheral at the same time?
by Darren Jones 11 Jan '13

11 Jan '13

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Re: Central and Peripheral at the same time?
by Etan Kissling 11 Jan '13

11 Jan '13

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Re: Central and Peripheral at the same time?
by Darren Jones 11 Jan '13

11 Jan '13

Thank you. I want to use non pairing so CoreBluetooth is the way. I'm glad it's possible. I wasn't sure if background scanning and advertising would be allowed. On 11 Jan 2013, at 16:02, Etan Kissling <kissling(a)oberon.ch> wrote: > Darren, > > If you want to perform iPhone to iPhone communication only, I suggest using GameKit for it. > You will have an increased throughput, as classic Bluetooth is used as a transport, and don't have > to worry about specifying who is master and who is slave. > > If you want to stay with CoreBluetooth: at least from the Bluetooth Core Specification, a device is > allowed to scan and advertise at the same time. I have not yet tried it under iOS, but can tell for your > background requirement that scanning times are pretty slow while backgrounded (around 55x > advertisement interval). Also don't forget to stop scanning and advertising as soon as you establish > a connection. > > Etan > > > On 10.01.2013, at 23:59, Darren Jones <djonesuk(a)me.com> wrote: > >> Is it possible to use CBCentral scanning and CBPeripheral advertising at the same time? (Also in the background) >> >> If I wanted 2 random iPhones to communicate and both where set to Central or both to Peripheral they wouldn't see each other. I'd like to remove that they would both have to know which method to activate. >> >> Is that possible? >> >> Thanks >> >> Sent from my iPhone 5 >> _______________________________________________ >> 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/kissling%40oberon.ch >> >> This email sent to kissling(a)oberon.ch > _______________________________________________ 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: Central and Peripheral at the same time?
by Etan Kissling 11 Jan '13

11 Jan '13

Darren, If you want to perform iPhone to iPhone communication only, I suggest using GameKit for it. You will have an increased throughput, as classic Bluetooth is used as a transport, and don't have to worry about specifying who is master and who is slave. If you want to stay with CoreBluetooth: at least from the Bluetooth Core Specification, a device is allowed to scan and advertise at the same time. I have not yet tried it under iOS, but can tell for your background requirement that scanning times are pretty slow while backgrounded (around 55x advertisement interval). Also don't forget to stop scanning and advertising as soon as you establish a connection. Etan On 10.01.2013, at 23:59, Darren Jones <djonesuk(a)me.com> wrote: > Is it possible to use CBCentral scanning and CBPeripheral advertising at the same time? (Also in the background) > > If I wanted 2 random iPhones to communicate and both where set to Central or both to Peripheral they wouldn't see each other. I'd like to remove that they would both have to know which method to activate. > > Is that possible? > > Thanks > > Sent from my iPhone 5 > _______________________________________________ > 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/kissling%40oberon.ch > > This email sent to kissling(a)oberon.ch _______________________________________________ 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: Central and Peripheral at the same time?
by Andras Kovi 11 Jan '13

11 Jan '13

It's totally doable. You simply have to initialize both managers on both phones and use them according to your needs. Regards, Andras On 2013.01.10., at 23:59, Darren Jones <djonesuk(a)me.com> wrote: > Is it possible to use CBCentral scanning and CBPeripheral advertising at the same time? (Also in the background) > > If I wanted 2 random iPhones to communicate and both where set to Central or both to Peripheral they wouldn't see each other. I'd like to remove that they would both have to know which method to activate. > > Is that possible? > > Thanks > > Sent from my iPhone 5 > _______________________________________________ > 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/allprog%40gmail.com > > This email sent to allprog(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: Bluetooth-dev Digest, Vol 10, Issue 9
by jing zhiwei 11 Jan '13

11 Jan '13

check and resend the lost data 在 2013-1-11，上午4:00，bluetooth-dev-request@lists.apple.com 写道： > Send Bluetooth-dev mailing list submissions to > bluetooth-dev(a)lists.apple.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.apple.com/mailman/listinfo/bluetooth-dev > or, via email, send a message with subject or body 'help' to > bluetooth-dev-request(a)lists.apple.com > > You can reach the person managing the list at > bluetooth-dev-owner(a)lists.apple.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Bluetooth-dev digest..." > > > Today's Topics: > > 1. Re: [BTLE] Sending (a lot of) data to a Peripheral (Etan Kissling) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 10 Jan 2013 10:44:07 +0000 > From: Etan Kissling <kissling(a)oberon.ch> > To: Roland King <rols(a)rols.org> > Cc: "<bluetooth-dev(a)lists.apple.com>" <bluetooth-dev(a)lists.apple.com> > Subject: Re: [BTLE] Sending (a lot of) data to a Peripheral > Message-ID: > <2857786638B63646B9685DEE12ED252203D75C0A(a)S0407.hosting.local> > Content-Type: text/plain; charset="utf-8" > > Roland, > > the flag for guaranteed transmission can be specified when you write a characteristic value. > You can find the definition in the CBPeripheral.h file. > > /*! > * @enum CBCharacteristicWriteType > * > * @discussion Specifies which type of write is to be performed on a CBCharacteristic. > * > */ > typedef NS_ENUM(NSInteger, CBCharacteristicWriteType) { > CBCharacteristicWriteWithResponse = 0, > CBCharacteristicWriteWithoutResponse, > }; > > > CBCharacteristicWriteWithResponse stands for a reliable transmission where you receive a callback > as soon as the write has been received by the remote device. > > CBCharacteristicWriteWithoutResponse stands for an unreliable transmission where you won't receive a callback. > > >> From the semantics point of view, writes without response may be discarded when buffers become congested. > However, even those packets will be transmitted either fully or not at all, and a relatively strong CRC check > protects against many categories of bit errors. > > On iOS, you can send one WriteWithResponse every two connection events. You can send WriteWithoutResponse > four times per connection event. Note that iOS 5 crashes sometimes, when you stream at too high speeds using > WriteWithoutResponse. iOS 6 increased the stability, however, I recall one case where it still crashed - much harder > to reproduce it, though. > > When you use the minimum connection interval that falls under the Apple Guidelines for Bluetooth Accessories, of 40ms, > then you can achieve up to 2 kbit/s for writeWithResponse and about 16 kbit/s for writeWithoutResponse. > Note that throughput varies depending on the angle in which you hold your iOS device on medium ranges. > > The same throughputs are available for the other direction, where indications are the counterpart for writeWithResponse, > and notifications for writeWithoutResponse. > > > Etan > > > On 05.01.2013, at 05:03, Roland King <rols(a)rols.org<mailto:rols@rols.org>> wrote: > > > On 5 Jan, 2013, at 11:30 AM, Anders Grunnet-Jepsen <anders(a)thinkoptics.com<mailto:anders@thinkoptics.com>> wrote: > > What we do is insert delays between sends. So between every packet we would insert delays so that the effective maximum rate would not exceed that which the system supports (20x4 bytes per connection interval). As a check that we don't lose data packet we would assign the very first byte to be an incrementing index. Note that you can't just insert a sleep command but you should program it as a timer so the iOS actually exits the runtime thread and waits between sends. > > Why did we go to all this trouble? We found that if we sent data with the flag set for guaranteed transmission, then the data rate would go down to an unacceptable rate. If we sent it without delays then we would start losing packets. > > > What is the flag for guaranteed transmission? I was searching the header files and couldn't find it. > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Bluetooth-dev mailing list (Bluetooth-dev(a)lists.apple.com<mailto:Bluetooth-dev@lists.apple.com>) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/bluetooth-dev/kissling%40oberon.ch > > This email sent to kissling(a)oberon.ch > >

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Central and Peripheral at the same time?
by Darren Jones 10 Jan '13

10 Jan '13

Is it possible to use CBCentral scanning and CBPeripheral advertising at the same time? (Also in the background) If I wanted 2 random iPhones to communicate and both where set to Central or both to Peripheral they wouldn't see each other. I'd like to remove that they would both have to know which method to activate. Is that possible? Thanks Sent from my iPhone 5 _______________________________________________ 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: [BTLE] Sending (a lot of) data to a Peripheral
by Etan Kissling 10 Jan '13

10 Jan '13

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Re: Is it possible to change scan parameters for BT LE scans?
by Jimmy Adler 10 Jan '13

10 Jan '13

Hi Etan, On Jan 10, 2013, at 10:45 AM, Etan Kissling wrote: > Jimmy, > > Regarding the incorrect data length that you observed: > > SCAN_RSP data uses an additional length header in front of the advertising data. Are you sure that > this 17th byte does not contain a 0x10 value, which would indicate a length of 16 bytes for the payload? > > The advertising data format is described in the Bluetooth Core Specification Version 4.0 Volume 3 > Part C Section 11. Yes, this is what I used to find out that the length was wrong, the raw message sent was: 11ff.... So 0x11 for 17 bytes length, 0xFF for ManufacturerData and then an additional 15 bytes (according to the length it should be 16). Of course in the IOS interface I never get to see the 0x11 or the 0xFF, since the packet is parsed by IOS and mapped to kManufacturerData and a payload. And since the payload is to short, the packet never reaches me :) > Regarding SCAN_RSP data in general: > > SCAN_RSP data should not be used for dynamic data, but for static data. Advertisement data is there > for dynamic data. I'm not sure how often iOS will query for updated SCAN_RSP data and how often it > will deliver the advertisement report to your app. > > Again quoting the spec, Bluetooth Core Specification Version 4.0 Volume 1 Part A Section 4.2.2.2 > confirms the guideline of what data to put where: > > "Advertising devices may receive scan requests from listening devices in order to get additional user > data from the advertising device. Scan responses are sent by the advertising device to the device > making the scan request over the same advertising physical channel. Whereas the broadcast user > data sent as part of the advertising packets is typically dynamic in nature, scan response data > is generally static in nature. " > > Summary: > - service data => advertising data (so that iOS can know if the device supports your requested service > before it has to request the SCAN_RSP data) > - static data like device name => scan_rsp data (takes longer to acquire) > - dynamic data like changing temperature values => advertising data > > > > Regarding the expected behavior of the Filter_Duplicates parameter: > > Unfortunately, the wording from the Bluetooth Spec is not very clear here, and I have not yet tested > HW with changing advertising reports in conjunction with a backgrounded app on an iOS device. > Therefore, you will have to go with try and error here, unless someone else can confirm or deny whether > repeated advertising reports are delivered to the app. Ok, will do some trial and error once I get correct HW. Worst case I will keep the thread awake in the background, this application will most likely be delivered outside of appstore using Enterprise dev program anyway, so it shouldn't be an issue. > The Bluetooth Core Specification Version 4.0 Volume 2 Part E Section 7.8.11 explains the LE Set Scan > Enable Command. > > > You can acquire a copy of the Bluetooth spec under www.bluetooth.org/spec . Thanks, got the nice 2200 page document when I was troubleshooting this previously, it's a lovely read ;) Thanks again, JImmy > > On 09.01.2013, at 14:23, Jimmy Adler <d99fish(a)gmail.com> wrote: > >> Hi Etan, >> >> thanks for your answers! >> >> I belive that I have found the issue. Using a PC for sniffing the packets I saw that the datalength of the packet was set to 17 bytes, while the packet only contained 16 bytes, so it is most likely the fault of the 3:rd party device which is sending the packet. I assume that IOS does not deliver the packet until it thinks all the data is available, which it will never be if there is to little payload in the data :) >> >> Since I don't have insight in the code on the device I have forwarded my suspicion to my customer and they will handle the discussion with the 3:rd party supplier to correct the issue in the HW! >> >> You did mention that there can be dynamic data in the scan response and that this will only be discovered once while in background mode. >> >> I noticed that with another HW I tested with, when I had the scanning option set to "not allow duplicates", I would still get updated advertisment packets with the changed dynamic data after a couple of minutes when activating the HW again (controlled by accelerometer in the device) is this the same behavior that I should expect to see when running in the background, or will I never get the updates at all when running the app in the background? >> >> Best regards, >> >> Jimmy >> >> On Jan 9, 2013, at 1:48 PM, Etan Kissling wrote: >> >>> Jimmy, >>> >>> one more update for my last message: >>> >>> The only scanning option that you have on iOS is whether you want to receive multiple advertisements for the same device. >>> If this is disabled, I'm not sure whether or not SCAN_RSP data is already included when the first advertisement is received. >>> Note that background scanning will always only send the first advertisement for each device to your app. >>> >>> Regarding device name in SCAN_RSP data: >>> A video of one of the projects I worked for in action, where the peripheral name is broadcasted as SCAN_RSP data, can >>> be watched under the following link. Note how it takes several seconds for all the names to load, even after the peripheral >>> has already been discovered. >>> http://www.youtube.com/watch?v=uqGF-Mtja-E&feature=player_embedded >>> (device list starts at 0:20) >>> >>> Etan >>> >>> >>> On 09.01.2013, at 11:15, Etan Kissling <kissling(a)oberon.ch> >>> wrote: >>> >>>> You cannot specify scanning options on iOS using public APIs. However, iOS supports active scanning. >>>> >>>> Note that you should put static data in your scan_rsp part as additional packets have to be exchanged to retrieve them. Dynamic data should be put in your advertisement data. >>>> >>>> I have not tested it but it may be reasonable that iOS does not send a SCAN_REQ for each and every advertisement report of the same device. Also, as the SCAN_RSP data arrives at a later point in time than the original advertisement data, you may not see it at all. >>>> >>>> What I tested in the SCAN_RSP data until now is only a partial device name. This works perfectly (but is not available on the first received advertisement yet) and is overridden as soon as you connect to the device with the name stored in the GAP service. >>>> As the name is managed by iOS, other rules may apply for custom SCAN_RSP data. >>>> >>>> I also suggest using the TI packet sniffer for ~50$ to see when the iphone actually sends these scan_req packets. >>>> >>>> Etan >>>> >>>> On 09.01.2013, at 09:59, "Jimmy Adler" <d99fish(a)gmail.com> wrote: >>>> >>>>> I have an issue detecting kCBAdvDataManufacturerData from a 3:rd party device using BT LE. I get the kCBAdvDataLocalName advertisement, but not the one containing the Data. >>>>> >>>>> When using a PC testapplication I'm able to get the kCBAdvDataManufacturerData by setting the scan_interval to 10ms and scan_window to 10ms and using active scanning. >>>>> >>>>> Problem is that as far as I can see, these parameters are not accessible on the IOS device, or can the paramters be sent in when starting the scan using the options dictionary in some way? >>>>> >>>>> Is this problem solvable without having access to and altering the code in the device? >>>>> >>>>> Best regards, >>>>> >>>>> Jimmy >>>>> _______________________________________________ >>>>> 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/kissling%40oberon.ch >>>>> >>>>> This email sent to kissling(a)oberon.ch >>>> >>>> _______________________________________________ >>>> 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/kissling%40oberon.ch >>>> >>>> This email sent to kissling(a)oberon.ch >>> >> > _______________________________________________ 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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