Working on a quick and fun project. I have 2 beacons at home: One attached to my dog collar and the other attached to my sneakers. Basically I want to get a notification at work on my phone whenever the dog gets close to the sneaker.
Actually, in general two beacons cannot communicate with each other. Reason being, both beacons are servers which can provide certain information. Mobile phones connect to them as a client and fetch information.
Now, since both the beacons are server they cannot connect to each other. To connect to each other either of them should be client. Which is not there in case of beacons.
Related
When I study Bluetooth, I am confused to understand Bluetooth connection and pairing, bonding, etc.
As far as I know, Bluetooth Connection has these steps:
Inquiry - discover
Paging - using the address in Inquiry process, process of forming a connection
Connection - device can participate actively(Active mode) or put into other mode(Sniff, Hold...)
When we use Bluetooth devices(e.g. Smartphone, Bluetooth Heaset)
it has these steps:
Discovery devices
Pairing(exchange other security information like address, PIN Code)
Connection start
I can't match paging to pairing. Is my understanding right below?
Inquiry = Discover Devices
Paging = Pairing
Connection = Connection start
How can I merge above two categories?
Not answered in 7-months! Oh, well for posterity...
Inquiry and Paging - Link Layer Connection
(Is there anyone out there? Hello!)
Inquiry and Paging are procedures and states of the Bluetooth Link Controller during the connection process.
The standard progression of states to a connection are as follows:
One device performs the Inquiry procedure, a request message for devices within 10-meters to respond, if they are in range. This device is the Master.
Devices that are discoverable, will respond with an Inquiry Response. Example: If you turn on the Bluetooth on your phone, it often states it is discoverable and then it will list a number of devices around you.
The Master device then will initiate a connection by paging a specific Slave device.
If the Slave device is amenable, it will respond with a Page response. Example: On your phone, you select the Bluetooth Headphones to connect with.
At that point lots of cool stuff happens so that the radios can match frequency hopping patterns and timing of radio packets. When it's over, and successful, you have a Link Layer connection.
Typically, there are two types of connection:
Asynchronous Connection-Less (ACL) - Packet data
Synchronous Connection Orientated (SCO) - Audio (or video) data, real-time.
Pairing
(security and remembering past lovers)
Bluetooth doesn't need any Security to do Service Discovery (the next stage) but all Bluetooth services need security, so pairing is nearly always done BEFORE Service Discovery BUT it doesn't have to be.
In the lowest level of pairing security, it 'just works'. Your phone says, it's connected and that's it. The link is encrypted but did you really connect to your headphones or your sister's down the hall?.
Once connected and encrypted like this, the phone may ask you if you want to stay paired with the headphones. If you select 'yes' or tick the box, your phone will remember the encryption and security keys for your headphones (as will your headphones for your phone). The next time they connect, they will recognise each other and just connect and encrypt the link without having to go through pairing again.
Now if your connecting your phone to your car by Bluetooth, you probably want better security. There are various options but typically it goes like this.
When it comes to pairing, your car system will display something like 'Pairing code 4753495' and your phone will display something similar like 'Verify pairing code 4753495 - Yes/No' - If they match, then you have a really secure connection and you absolutely know that your phone is paired with your car and not you're sister's rubbish Toyota out on the drive.
Bluetooth these days is really secure, the latest specs support US Secret Service levels of encryption and for that reason some Bluetooth firmware and devices have strict export restrictions. Older, legacy devices will still use 4-digit pin codes and are less secure.
Service Discovery
(What can you do?)
The Master will ask the Slave to tell it a little about itself and the Slave tells the Master all the cool things it can do. The Master will reciprocate too.
With our Headphones and mobile phone example, once you pressed on the Headphones in the list of devices, it will connect, pair and you will get a pop-up saying it supports things like 'Phone Media' (Handsfree / Headset Profiles) and 'Music Media' (Advance Audio Distribution Profile, Audio/Video Remote Control Profile, and some protocols under that).
Your car, in addition to Phone and Music Media, can probably do things like browse your Phone's contacts or even display text messages.
Profile/Service Connection
(Finally)
After all that, you're set up. Typically a profile/service level connection doesn't happen until you try and use it .e.g play music or make/receive a phone call but the Link Layer connection is there underneath.
So, you can start playing music on your phone and the sweet beats will magically come out of your headphones or car stereo...
Until your sister calls.
I'm not sure how to correctly phrase this question, as I'm just starting to learn Bluetooth and its ways, but... imagine holding in an iPhone or Android phone in your hand in a large building with many rooms. You pair your device with a Bluetooth master device via an antenna in that room. Then once you move from room to room, your device communicates with other antennas throughout the building, but the device treats it as one pairing.
Is this at all possible? Was Bluetooth developed with this in mind at all?
Would this still work if the antennas were wireless? My idea is for devices to communicate with nodes via Bluetooth, and nodes interact with central base via wi-fi/local router.
Also, third random question: how does using BLE affect any of this?
Please tell me if I'm crazy! Thanks!
Bluetooth 4.0 BLE allows for a slave to connect to one master. 4.1 BLE allows for more than one connection, but I don't know if anything implements that yet.
Either way, there's no sort of "roaming" method pairing devices like with wifi access points with the same SSID. BLE however doesn't require pairing like regular Bluetooth, so you could just connect to a new access point each time you lose a connection.
You can also communicate via advertising packets from the "antenna" in each room. This would facilitate information being passed from those rooms to the phone, but not the other way around. This is basically how you communicate with BLE when you don't pair/connect devices and is how iBeacons work.
If you're writing the software yourself, and installing it in the building and on the phone, then I think it should be totally possible. Bluetooth devices can detect the distance and direction of other bluetooth devices. So if both devices are running software that is designed to, and grants permission to do so, it should be no-big-deal to programmatically auto-reconnect to the new nearest antenna whenever one becomes significantly closer than the one that your phone is currently connected to. As for software that already does this that you wouldn't have to develop from scratch yourself, no idea.
Can Two Bluetooth LE (4.0) Devices talk to each other ?
A good example can be if two FitBit devices talk to each other .Just pass basic information ?
or One Coin Device communicate each to other ? (https://onlycoin.com/)
As of today we see most BLE Devices like fitbit communicate back to Iphone/Android Only .
Wont it be possible to have both FitBit deices communicate each other ?
I am thinking of creating a "Card 1: Bluetooth Card(LE 4.0)" which when Contacted with another "Card 2: Bluetooth Card(LE 4.0)" can exchange some date . After the exchange Card 1 will send the data it got from Card 2 to an IOS /Android device and the same applies to Card 2 . Is this possible at all ?
What you want to achieve is currently not doable. Bluetooth Low Energy (v4.0) only allows the star topology configuration, i.e. Only one master and multiple slaves; the master can talk to the slaves at the same time but the slaves cannot talk to each other. According to the Bluetooth website, they state:
"Bluetooth low energy technology uses a 32 bit access address on every packet for each slave, allowing billions of devices to be connected. The technology is optimized for one-to-one connections while allowing one-to-many connections using a star topology. With the use of quick connections and disconnections, data can move in a mesh-like topology without the complexities of maintaining a mesh network".
One way to achieve what you want is to switch roles between transmissions (i.e. the device that was once a slave then becomes a master) but this will be very complicated and many BLE chips do not support this feature.
I hope that this helps.
I'm currently thinking of developing chess code with multi-player facility connected and played via bluetooth. For that I need to chalk out the phases, i mean systematic modules, that I should follow to develop the game. If anyone can state it or have any link that can help it out, it would be great.
Another thing I am developing this in J2ME, so can anyone give me an idea about the way to connect the game in two mobile devices through bluetooth in J2ME. I mean to say the class or file that is used to connect the gaming devices.
For the second part of your question: you need to make an SPP (serial) connection between the two devices, with one acting as a client and the other as a server; see this tutorial for more information.
Then you need to create your own protocol to allow the two devices to communicate everything they need to.
This will only work on handsets with JSR 82.
The GameKit in iPhone SDK 3.0 create a peer-to-peer bluetooth connection between two iPhones, using Server-client model. In the bluetooth spec, up to 7 clients can be connected to a server. But in GameKit document, there is no words for this issue. Does it means a GameKit server can connect more than 7 clients? If yes, does that mean some clients is in sleep mode?
Thanks!
I've been looking for a definitive answer for this for months. There isn't one as far as I can tell. I keep going back to Volcore's blogs on the "woe's of gamekit" where they detail getting up to 4 devices connected over Bluetooth with very unreliable results. All Apple's demos point to "two devices connected" to be the ideal GameKit situation. I eschewed BlueTooth in favor of Wifi in the game I am developing since I knew that I could definitely get more connected (I needed up to 6 players—wasn't convinced I could make it work with BlueTooth). I've found it to be no problem to get 3 devices and simulator talking to each other (though It's not a real-time game—it's turn based—so the data sends are small and infrequent). My guess is that GameKit over bluetooth would not support more than 7 clients.
I've been working on a little app to broadcast messages to multiple iPods. It seems rather unreliable to use bluetooth for any more than two clients (assuming you're setting up a client-server architecture). I'd recommend using cocoaasyncsocket for communicating with multiple clients. I think you'd need a router though.