I want to send data from one iPhone device to another iPhone device, in that one device work as transmitter and other work as receiver. Receiver can also send data to transmitter(server).
So is there any way using code to do this ?
iBeacon is a transmit-only proximity technology, that's why it's found in the Core Location framework. It is not designed, nor does it support, bi-directional communication. An iBeacon advertises its presence and that is all.
If you want to perform data transfer over Bluetooth, have a look at the Core Bluetooth framework and its samples, such as the CoreBluetooth Temperature Sensor sample.
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We're looking to build a small device connected to a sensor that transmits data to an iPhone, which subsequently takes the data, stores it and graphs it. However we want the iPhone to be able to change the polling data on the device by sending small amounts of data. I've been doing some reading and it seems like bluetooth LE does not allow for this type of streaming connection. Is this correct? Would switching to an Android platform be better? What would you all suggest?
With Bluetooth LE, you have complete control over the flow, even on iOS.
That said, there are a couple of things to know:
BTLE devices only have read-only "characteristics" (but can be dynamic)
There is no way to "push" data, only notify a change to the listening devices
So instead of saying - "Hey, 'streaming_type' should change from 'wind' to 'temperature'", you would say - "Hey, 'streaming_type' has changed, come read it".
It is not specific to iOS, it is the way BTLE works. So if you want an iPhone to be able to control your device, your application simply needs to setup a BTLE "streaming_type" characteristic, and then update it when the user wants to change the type of data being streamed.
Your BTLE device would then look for this specific "streaming_type" characteristic, and go read it when it receives a update notification.
I'd like to ask whether it is possible to access the raw advertisement data from a custom BLE device built using a Raspberry Pi from the Core Bluetooth API?
The use case is to broadcast constantly changed data from the Raspberry Pi to multiple iOS devices in the proximity and consume them in an iOS app. See the topology description in this article.
I already found out that the iBeacon advertisements are filtered out from the Core Bluetooth API and are only accessible from the Core Location API only, which requires the knowledge of the UUID. Due to the constantly changed data a custom iBeacon wouldn't work for this particular use case anyway. But I am unsure whether I could achieve that with Core Bluetooth?
You can do what you want if you change the Raspberry Pi to transmit a non-iBeacon format. CoreBluetooth only filters out the raw bytes of advertisements if they are iBeacon advertisements. See here: Obtaining Bluetooth LE scan response data with iOS
A simple solution is to change your iBeacon advertisement to an open-source AltBeacon advertisement. CoreLocation will no longer pick it up, but CoreBluetooth will.
Here's an example of what you get in the advertisementData NSDictionary in the CoreBluetooth centralManager:didDiscoverPeripheral:advertisementData:RSSI: callback. This example is the result of detecting an AltBeacon advertisement (an open-source beacon standard), with identifiers 2F234454-CF6D-4A0F-ADF2-F4911BA9FFA6 1 2:
{
kCBAdvDataIsConnectable = 0;
kCBAdvDataManufacturerData = <1801beac 2f234454 cf6d4a0f adf2f491 1ba9ffa6 00010002 be00>;
}
You can see how to decode the above bytes by looking at the AltBeacon spec here. Note that the above are the actual contents of the NSDictionary for a detected advertisement on iOS8 that were printed to the console using an NSLog statement.
Quick answer is "there is no direct way".
Why:
Because CoreBluetooth filters out advertisement data, except kCBAdvDataServiceUUIDs, kCBAdvDataLocalName, so there is now way to pass custom data from peripheral to central via advertising.
How can we workaround:
Peripheral
1) Holds some custom service (let's name it 'BeaconService').
2) BeaconService contains Beacon's UUID, major, minor characteristics.
3) Advertises BeaconService UUID (via kCBAdvDataServiceUUIDs key).
Central
1) Scans for peripherals that have BeaconService UUID.
2) Found peripherals are queued.
3) Connection is opened to queued peripherals, and the iBeacon information is read from BeaconService.
4) Read values can be used to start CoreLocation beacon monitoring/ranging.
So by this way you can make bridge from CoreBluetooth to CoreLocation.
When you start advertising a CLBeacon with peripheral data, can you pass in a NSString or UIImage into this dictionary that you could then have show up when the beacon is discovered?
For example, if I wanted to create write a message to a friend and then when the friend entered the beacon area, could I have the message show up on their phone by storing the message in the NSDictionary and then extracting it? If so, how? If not, is there another way?
Thanks!
So you are asking if you could add extra information to the beacon advertisement that's sent by a beacon device that a custom application could look for?
The answer is no. The iBeacon protocol is a very short, fixed packet of data. There's no facility for adding extra information to the packets.
You could design and implement your own BLE service that's an alternative to iBeacons and implement it on both the transmitter and the receiver.
You could also use a hybrid approach, where you use standard iBeacon discovery to find beacons, and when you detect a beacon you're interested in, trigger a 2-way BLE conversation with the beacon and ask it for additional information. It's my understanding that some of the BLE devices that are being sold as iBeacons can run custom software that would implement this sort of thing. (Many of these devices have ARM processors in them, the same family of chips that power iOS devices.
No, you cannot do this. iOS-based iBeacons (like all other standard iBeacons) will only transmit a three-part identifier and a transmitter power calibration value. That's it. You cannot transmit anything else.
Even if you did make a custom Bluetooth LE advertisement that sends additional data besides the standard iBeacon fields, you wouldn't be able to see this data with the standard APIs for seeing iBeacons.
If you want to tie other data to an iBeacon, you have to do it through another channel, by some kind of lookup that matches the data up with the identifiers above. Three common ways to do this:
Hard-code a static lookup table in your app.
Use a Web Service to look up the value based on the iBeacon identifiers.
Fetch the data directly from a (non-standard) iBeacon using a secondary BluetoothLE communication channel.
My company has a web service called ProximityKit that makes it easy to tie data to iBeacons in your app. You log into a web interface to type in key/value pairs to associate with each iBeacon, then the included iOS client library automatically gives you those key/value pairs when the iBeacon is visible.
how is it possible to send data to an iPhone which acts as an iBeacon?
I am looking for an process as the following:
Search nearby iBeacons
Connect to some iBeacon
Exchange data between the devices
Does anybody know how to put the different bluetooth functions together to make
this possible?
thx in advance
Standard iBeacons are transmit-only devices that can be seen by mobile devices, but don't actually "connect" to them or exchange data.
But you can still do what you are asking if you have an app on all devices as well as a web service to do the data transfer. This would allow devices A and B to detect each other when they are nearby and exchange data. Here's how:
Your app on devices A and B alternates between acting as an iBeacon (advertising its presence with an application-specific identifier and a phone-specific identifier) and ranging for iBeacon signals including the application-specific identifier.
During its ranging cycle, your app on device A will detect an iBeacon transmission from device B, which includes both your application identifier and the device identifier of B.
App A then makes a "write" call to the web service with a source of "A" and a destination of "B", along with any data you want to transfer, like "Device A says hello to device B."
The app would also periodically make a "read" call to the web service. In this example, device B would read any information destined for B, and the web service would return a record that device A had send it a message with the data "Device A says hello to device B."
Because the same process is also running on both phones, this communication can happen both ways.
iBeacon is a proximity technology and isn't designed for data interchange. However, since the Bluetooth stack is going to be active on your iPhone acting as the beacon (so it can advertise its proximity UUID), you can use Core Bluetooth to connect to the beacon and exchange data between the devices.
Does it specifically need to use iBeacon technology? The reason I ask is that from reading your description of the process, you could achieve the same thing using iOS 7's Multipeer Connectivity. It's able to abstract out all the technical complexities of connecting 2 iOS devices together regardless of the interface, be it WiFi or Bluetooth. I've managed to build something similar using MCNearbyServiceBrowser, MCNearbyServiceAdvertiser, and MCSession classes.
I'm developing an iOS app with an accompanying Bluetooth LE peripheral. The one step I don't seem to be able to solve is how to actually transmit the data from my app to the peripheral or vice versa.
What I've built so far is a test app that can connect to my sample Bluetooth peripheral, and read all of its services/characteristics/descriptors. It can toggle notifications for a given characteristic, and write to given characteristics. It is just this last step of "transmit n bytes to the peripheral, and receive m bytes from the peripheral" that I can't seem to figure out.
Looking at the External Accessory Framework (what I would use if Apple would actually give me MFi approval for this project), they give you input and output streams on a given session to communicate with the accessory, but no such object exists for CoreBluetooth.
Is this simply an oversight on Apple's part on the functionality of CoreBluetooth? Or do I simply need to develop my own Bluetooth service profile to handle the inflow/outflow of data to and from the peripheral?
LE is fundamentally designed to work with these GATT based profiles, which are suited for monitoring sensors, not for data streams. While LE does allow for additional L2CAP streams to be opened for custom protocols, Apple's CoreBluetooth doesn't provide access to do so.
You can build a custom profile with private services and characteristics and have it work kind of like SSP; that's the way I'm using my BLE module to get data from some sensors to my app. The module I bought (Microchip's RN-4020) already has a custom profile made specifically for this known as MLDP (Microchip Low-energy Data Profile).
The way I get the data in my iOS app is by subscribing to the private characteristic, thus being notified when the values are updated. So far it has been working great, and the data rate can go up to 20 kbps according to Microchip (I haven't tested its limits, since I don't need much speed). Here's a link to Microchip's product page: http://www.microchip.com/wwwproducts/Devices.aspx?product=RN4020
Good luck!
You can use the bluetooth.org 'Immediate Alert Service' uuid=1802 with characteristic uuid=2A06 with property=write_no_response to send one byte values to your peripheral device from your iPhone. The peripheral device must be programmed to act on the data that is sent. For example, you might use a button on an iPhone app to send a hex address that causes one or more port pins to turn on or off on the peripheral. While this is not using the Alert Service as it was intended, it does provide an easy way to test out data transfer to a peripheral device. The same process could be used to send sequential data bytes similar to a serial data stream. I have not yet tried sending more complex data streams. The write_no_response does not provide any feedback to the app as to whether the data was received by the peripheral.
The IOS TemperatureSensor.xproj is an example of code for reading temperature data from a peripheral. The OSX HealthThermometerClient.xproj has the code needed to decode the somewhat complex thermometer data structure. The IOS TI-BLE-Demo.xproj TIBLECBKeyfob.m has code for reading and writing characteristic values, such as, reading temperature or battery levels from a peripheral device.