I am looking to write application for iPhone which will be able to control radio and CD player in car. Radio and player have Bluetooth connection available.
I started this question in order to obtain all informations I need for this one one place. I have few questions, but if you find anything I didn't ask important for me to start developing this application, please, let me know.
I have read about AVRCP profile and Bluetooth device in car supports AVRCP 1.3, which is good enough for me, having in mind controls which can be performed in that protocol version.
I read a lot about people saying "Apple device can only interact with each other", "Apple device can't be connected via Bluetooth to non-Apple device", "MFi program is obligatory if you want to do that", "MFi is not needed", etc. My first question is:
1)Is it even possible to pair iPhone (4, 4S) with radio and CD player in car via Bluetooth and control radio stations and music with any iPhone version? If yes, what are the limitations for making this kind of successful Bluetooth connection?
There is also very few informations about roles in which iPhone can work. For AVRCP there are two kind of roles: controller and target role. By reading this paper: https://developer.apple.com/hardwaredrivers/BluetoothDesignGuidelines.pdf I didn't find answer to my second question:
2) Can iPhone act as a controller and issue all available commands stated in AVRCP 1.3 to target device (radio and CD player)?
I would also like to know about available frameworks for this particular problem. I know there are several of them, but if anyone recognizes the right one for my problem, I'd like to know:
3) Which framework for interacting with target device should I use?
From developer point of view, I am also interested in available APIs for interacting with connected Bluetooth device. Since I am making my own application and assigning actions to buttons, inside of methods assigned to buttons I need to perform message sending to target device. So my next question is:
4) Does anyone know how if there's a way to send commands to target device (start/stop/pause/forward/backward, etc) as part of some API provided in XCode, or each message which I attend to send via Bluetooth to target device I need to make according to protocol documentation (make entire message (header, body, command part, etc) by myself)?
AVRCP was my thought for accomplishing this application. If I am wrong, please let me know.
Bluetooth has different profiles and when message is sent from one device, as far as I understand, profile itself handles message and interprets it and delivers to target device so target device can understand it. I do not understand how a message sent from iPhone to target Bluetooth device is handled from the moment I send it from my Objective-C (or C) code. That's the main doubt I have and it is related with question 4 - do I need to make raw messages in correct format in order to send AVRCP commands to device or I can use some API which will recognize those messages as AVRCP (or any other kind) and deliver it to target device?
This last question (if I suppose there is any kind of positive answer to all previous) concerns me the most from developer point of view. So, if anyone had maybe experience with this specific problem, I would appreciate any kind of answer or advice.
I am really looking forward to your answers. I hope that constructive and useful discussion will start on this topic and that lots of useful informations will be written.
Best regards.
You can do it using CoreBluetooth if your device (CD Player) is Bluetooth 4.0 LE compliant
Most likely you shall not be able to do it even if your car CD player has BLE 4.0.
With Core Bluetooth devices act as "Central" (client) or "Peripheral" (server), the peripheral "has data" and expose services with characteristics (variables). The central (client) reads data from the peripheral or subscribe for notifications.
Your only chance is to connect to the CD player as peripheral (server) and your iPhone being the central (client). In this case the CD player must expose services that allow you to control it. To be honest I do not know how this can be done, since the central (the iPhone) will read data and receive notifications from the peripheral, not vice versa.
Reversing roles, implementing iPhone as peripheral makes sense, but there is no predefined Bluetooth LE service for remote control, so your car CD player does not know what service to expect from you. It might work using HID service (Human Interface Device), used in general for keyboards and mouse, but according to this post the HID is forbidden by Apple on iOS.
Related
I am trying to prototype a solution to a problem and am currently exploring multiple routes I could try. Is it possible for one iOS device, running a certain app, to communicate directly with another iOS device, running the same application - without the need to be on the same LAN?
Solutions I am currently investigating are using Bluetooth and ad-hoc wireless connections.
Ideally, the application when installed would ask the user for the required permissions, and then would accept and/or send data to/from another client after a handshake had happened.
My concern with Bluetooth is that 'pairing' would need to happen with every device, rather than happen in the background once the user has installed the app. I have a feeling what I am talking about isn't possible from what I've been reading elsewhere on Stackoverflow.
Take a look at Bluetooth Low Energy.
https://developer.apple.com/library/ios/#samplecode/BTLE_Transfer/Introduction/Intro.html#//apple_ref/doc/uid/DTS40012927
Here is another example,
https://github.com/KhaosT/CBPeripheralManager-Demo
You might also want to look into GameKit and peer-to-peer connectivity there.
I can't tell you anything about it, but you might try looking at iOS 7. If that's an option, I'd take a look. Can't talk about what it is because of NDA though.
Depending on what you need to communicate, you could try checking out this project, which lets you share arrays of strings between iOS devices over Bluetooth LE.
You don't need to "pair" the devices and it can still communicate while the app is in the background. SimpleShare
Hope it helps!
From the documentation of MultipeerGroupChat:
MultipeerGroupChat sample application utilizes the Multipeer Connectivity framework to enable nearby users to discover, connected, and send data between each other. This sample simulates a simple chat interface where up to 8 devices can connect with each other and send text messages or images to each other. Here you will learn how to bring up framework UI for discovery and connections and also how to monitor session state, listen for incoming data and resources, and send data and resources.
This is an excellent example at developer.apple.com here is the link
https://developer.apple.com/library/ios/samplecode/MultipeerGroupChat/Introduction/Intro.html
Also this tutorial from Ralf Ebert demonstrates how to use Multipeer Connectivity framework for peer communication should help you.
https://www.ralfebert.de/tutorials/ios-swift-multipeer-connectivity/
I have been searching and searching, but found nothing yet. Is it really true that there isn't a straightforward way to establish a BT connection from my iPhone to another (3rd party) BT device, i.e. an audio receiver. I know this is possible through the OS (I own a Belkin BT music receiver that works this way - it appears in Settings and from there I can connect to it). Note that I am not interested in pairing to iOS-devices, but an iPhone and my custom made hardware.
I've managed to find Google's BTStack at code.google.com, iBlueNova, Celeste and more, which all must be run through Cydia or similar and also I stumbled upon Apple's MFI-program, which seems fairly complicated.
Does anyone have any experience with bluetooth and iOS, if so, how and where do I get started?
If one might be interested, the project I am developing involves a piece of hardware with a BT device attached on it. The app should be able to send simple commands via bluetooth (basically just ASCII characters) to the device, which will react depending on what it receives.
If you are developing accessories that need to connect to iOS devices and want to use your own communication mechanism then your only option is to join the Apple MFi program.
Is it possible to detect and respond to the answer/end-call button presses from an HFP Bluetooth device on iOS? Has anyone seen this? Where should I look for answers? I understand one could get access to lower level bluetooth if you register for the device manufacturer (MFI) program but I'm hoping I don't have to dive this deep. I also know that you can respond to AVRCP commands but I am not wanting to use this option. Can anyone help?
UIResponder has a -remoteControlReceivedWithEvent: method that you can use to receive events from external devices, possibly including Bluetooth headsets. From the docs:
Remote-control events originate as commands from external accessories, including headsets. An application responds to these commands by controlling audio or video media presented to the user. The receiving responder object should examine the subtype of event to determine the intended command—for example, play (UIEventSubtypeRemoteControlPlay)—and then proceed accordingly.
To allow delivery of remote-control events, you must call the beginReceivingRemoteControlEvents method of UIApplication; to turn off delivery of remote-control events, call endReceivingRemoteControlEvents.
It’s not clear whether the answer/end button on a headset is considered equivalent to the play/pause button on, say, the earbuds’ remote, but this might be worth a try.
Sadly, there are no available bluetooth public APIs for developers, so no way to get that access in the conventional means.
As of my research, some person received some event from their bleu-tooth devices via "remoteControlReceivedWithEvent" but not all of them! Some are receiving none! And very few are receiving all of them!
I also tried Core Bluetooth but it only supports LEB (Low Energy Bluetooth devices)!
https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/CoreBluetoothOverview/CoreBluetoothOverview.html#//apple_ref/doc/uid/TP40013257-CH2-SW1
Also, some posts suggest it is possible to use Classic bleutooth instead of "Low Energy":
How to use bluetooth classic instead of le
But it has limitation as well (the post is taking about "MFi accessory"! MFi is it for "made for iphone" ?!?!?!)
from the post above:
"A non-LE Bluetooth device needs to be MFi-approved to be used with the External Accessory framework (it needs to use a specific Apple chip and a proprietary communication protocol). You won't be able to build applications to access this device unless it either uses the more open Bluetooth LE or has this chip in it for standard Bluetooth. There might be ways to do this via jailbreak, but pretty much everyone I know has moved over to Bluetooth LE." !
more post: Connecting to a Bluetooth device from iOS, no MFi
Regards.
Intro: I have a Denon S-52 internet radio with an iPod/iPhone dock (the older 12V kind, so charging is not possible with newer devices but audio/control data is passed through). The radio has an external clickwheel-like control that worked beautifully with iPod nano/classic etc. Since the iPhone/iPod touch no longer have any clickwheel functionality, the signals from the Denon clickwheel no longer have any effect while playing (ie no seeking), but can navigate through some menus on iOS, and play/pause works. The few clickwheel apps I've tried obviously ignore the external signals.
Questions: How hard would it be for someone with no iOs programming experience (just C/C++/C#, plus an objective C tutorial from lynda.com) to develop a basic audio player app that would accept signals from the external Denon clickwheel to seek within an audio file (for my own use, at least at first)? I'm assuming this is possible because the signals are sometimes processed (as mentioned above), but I'd be happy to be proven wrong before I waste a lot of time and effort. I also assume a standard $99 iOS developer membership would be enough (since the device itself is already MFi)? Or perhaps an app that has this feature already exists?
How hard would it be for someone with no iOs programming experience (just C/C++/C#, plus an objective C tutorial from lynda.com) to develop a basic audio player app that would accept signals from the external Denon clickwheel to seek within an audio file (for my own use, at least at first)?
Nearly impossible. It's not just the challenge of figuring out how to access the dock connector and interpret the signals of interest. The real problem is that you want to use those signals to control music that's playing, and you're probably thinking of trying to control the iPod application rather than writing your own music player. Communicating between two apps is difficult at best, and probably not possible if the target app (iPod) doesn't provide a mechanism for external control. And the fact that you're new to the platform doesn't make any of this easier.
Your best hope is probably to file a bug with Apple requesting this feature and hope that they'll add it for you.
I was able to do this by jailbreaking my iOS device, which enabled me to access the serial port for iPod Access Protocol communication at /dev/tty.iap. Then I could incorporate something like the functions found in this iPhone Serial Port Tutorial (check archive.org if the link no longer works) to read the incoming signals and respond accordingly.
Update: An even better solution seems to be to write a tweak hooking into the iPodUI private framework and intercept the commands directly, and then message the Music player about what to do (see this post for more details).
I'm in the process of planning out a personal project that will be a media player and one of the things I would like to do is be able to dock my iPod touch (or any iPod or iPhone) and control it and play music off it like the speaker docs do that you can buy.
I found some information while searching around online for this but my question is can I make up a cable and use the serial protocol from any device or does Apple have this locked down so only certified/approved devices can communicate this way?
If you are looking to do this for yourself, I would recommend jailbreaking and the following resources on the web. These describe some methods of the Apple Accessory Protocol, and include some parts (at sparkfun) to execute. To get approved for the Apple method you need a corporation (or similar structure) and even legal counsel before you can get approved to even see the agreement you have to agree to in order to join.
http://nuxx.net/wiki/Apple_Accessory_Protocol
http://www.sparkfun.com/categories/101
There are even some great articles out there such as:
http://courses.cit.cornell.edu/ee476/FinalProjects/s2007/awr8_asl45/awr8_asl45/index.html
Good luck!
EDIT:
Since this is a relatively popular post, keep in mind that you can now use Bluetooth 4.0 LE for serial communication without approval from Apple (other than AppStore approval).
https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/AboutCoreBluetooth/Introduction.html
Only devices in the Made for iPod program which use Apple's proprietary authentication chip can communicate with the External Accessory framework on the iPhone or iPod touch. Such devices must also expose a protocol that iPhone applications can use.
It is a reasonably involved process to be approved as a Made for iPod vendor of products (similar to the App Store approval process, but for hardware), but it has become a lot easier than it used to be. With iPhone OS 3.0, Apple has opened up the program to many more third parties than just the usual large accessory providers.
In your case, I'd actually wait and use another vendor's iPhone-controllable stereo. Manufacturers are just starting to come out with hardware controllable via iPhone applications, so it's only a matter of time before one of the larger accessory providers creates something like what you want. If they expose a protocol for controlling the device, all you'll have to do is write your application to control the device via that protocol.