I read a lot about Bluetooth LE in the past hours, but I do not really understand how profiles work. I want to pair an iPhone with a self-made device over BTLE.
The device should send measured temperature values, humidity or other values over Bluetooth and the iPhone should read that data.
I read about different profiles in the BTLE specs (even about heart measurement), but how does one proceed, when reading CO-emission for example?
Thanks a lot!
Regards, mary
There are two sides to this: the profile you'll define on your device and the code you'll write to communicate with this profile in your iOS application.
On the device, you'll define a profile with specific services for the measurements you want to gather. There are several standard Bluetooth LE profiles which you can find in a list on the main Bluetooth developer site. These include profiles for temperature, heart rate, and walking cadence, among others, so if you are providing measurements in one of these categories you can make your device provide one of those services and it will be usable with any iOS application that reads from that service.
For values that aren't covered by one of the existing services, such as the humidity readings you mention, you'll need to create your own custom service. You'll just have to define the service characteristics (what type of data you'll provide and how you'll provide it) and give this service a unique identifier, because it's one you're creating and not part of the standard ones laid out by the Bluetooth organization.
How you define these services and characteristics will depend on the specific Bluetooth LE hardware you use for your device. I've done most of my work recently on Bluegiga's BLE112 chip, which combines a low-power microcontroller with a Bluetooth LE transmitter. They have very good tools for defining device profiles and creating matching firmware, and it's reasonably straightforward to set this up on their chips. I can't speak for other manufacturers, but they most likely have something similar.
Once you have a profile defined on your hardware, you'll need to look for devices advertising it and be able to connect to them within your iOS application. You'll use Core Bluetooth for this, and I highly recommend starting with one of Apple's sample applications, such as their Temperature Sensor example. That example uses the standard health thermometer profile, but you can tweak it to find your proprietary services in addition to the temperature readings. You can see how they read and process the binary data returned from the LE device in that example.
I highly recommend watching Apple's two WWDC 2012 session videos on the topic, Session 703 - Core Bluetooth 101 and Session 705 - Advanced Core Bluetooth, because they provide a lot of background on the topic and show practical examples of this in use.
Related
I'd really love to learn to program cheap sensors and modules such as this one:
barometer sensor nRF51822 bluetooth module ibeacon LPS22HB, CR2032 battery holder, specifically to use within iOS and Swift.
I reached out to the company who makes them and tried researching how to get started multiple times, but I really can't figure out where to start. There are also pre-programmed modules, but my interest is programming these cheap ones to fit my needs.
I have the linked module, and a few others, and they appear and can be connected to using beacon detector apps, but display no understandable info.
I'd like to read the barometer pressure reading to start. Help is highly appreciated, I'd love to start working with these.
EDIT/UPDATE: I was able to read the modules manufacture name on one of many iBeacon scanner apps I tried and their name is Yunjia. With this information I am able to find alot more details online about what I have. One website says for these chips I can use LightBlue (the app I used to find the manufacturer name) to modify, read, and write to the module. Any additional advice is welcomed, I'll be researching and testing things out.
I also found the Schematics along with some additional info hidden in the seller website.
Edit 2: I found the manufactures little YouTube channel with some info, looks like I just have to do lots of research and testing and learn everything. https://www.youtube.com/channel/UCvqhWNqDE-v0je0X8XAEF2Q It contains some video instructions.
Edit 3: My short term goal of reading the barometer data was a success! After tons of digging I found I just had to write a value of 0x01 to turn on all sensors, then I was flooded with data and the barometer pressure in bytes which could be translated to the actual amount. Write 0x00 to trun off all sensors.
Apple's iBeacon framework is dirt-simple and very easy to use. It allows you to listen for beacons based a unique UUID, major id, and minor ID. It lets you know when a beacon enters or leaves range, and provides crude (immediate, near, medium, and far) distance values. You can create "beacon regions" that will notify your app when you enter or leave them. That's about it.
If you want to do something like read barometric pressure or temperature readings, you will need to either write your own low-level BLE code or use an existing library. My guess is that these modules are using very standard hardware and that you should be able to find libraries to read their specialized data.
Failing that, you will need specifications on their BLE interface and need to learn how to write Apple Core Bluetooth code. (The link you posted has zero specifications for the units. The only thing it provides is the numbers "nRF51822 bluetooth module ibeacon LPS22HB" (It's not in well-formed English so I don't know how to parse those descriptive terms. I'd google those numbers) Note that Core Bluetooth is a fairly low-level framework and not very easy to learn.
EDIT:
Googling "nRF51822", that is apparently an ARM based chip that includes radio hardware that supports BLE. It sounds like that is a general-purpose chip that vendor would use to build a BLE module. Given that, you'd probably have to reverse-engineer it to figure out how it works.
The "LPS22HB" appears to be a solid state pressure sensor that can be used to build a barometric pressure measurement device. It's no doubt interfaced with the "nRF51822". Without specs you're going to have a very hard time figuring out how it's interfaced however.
I'm developing navigation system for my university as some kind of research activity. I'm using SVGKit to display floor plans. And now I need to provide user locationing service for navigation and tracking. So here's my questions:
1) Do I need some special hardware installed in university (Cisco MSE for example, or some cheaper analogues), or I can apply some software/technologies to our current hardware for server-side user location determining? If I do, what equipment do I need for it? I mean, it would be one unit for the whole university, or one per each floor, or what?
2)
Q: Why doesn't the Redpin iPhone client conform to the iPhone SDK
Agreement? A: Apple does not provide a public API to retrieve WiFi
data. In order to get the iPhone client working we had to use a
private API, which is disallowed by the iPhone SDK Agreement.
(c) http://redpin.org/faq.html Does it mean that RedPin is unacceptable in AppStore, so I can't use it?
3)Does Navizon I.T.S. requires some specific hardware equipment except standart routers?
Thank you all, maybe you can offer me better solutions, I hope. Thanks in advance.
Indoor positioning is a very vast field and many different solutions are available which all use a different combination of hardware/software. Some need no specific hardware to work, others need a very expensive infrastructure to be put in place. In the end, it all depends on the accuracy you are trying to achieve. Here are the most common solutions used, I ordered them by the type of technology used:
Wifi: two main techniques are used here, trilateration and fingerprinting. Both do not require specific hardware if your uni already has deployed access points (APs). Trilateration converts signal strength to distance and then intersect circles (almost exactly like GPS). In general this has poorish accuracy and you need to know the exact position of APs for it to work. Fingerprinting is a pattern matching technique where you first build a wireless map of the environment and then match the measurement against this map.
Bluetooth: same techniques as above can be used with Bluetooth nodes. Of course, there's less Bluetooth nodes than Wifi so you might need to deploy some extra nodes for it to be accurate enough. Same accuracy as Wifi (roughly 5 meters)
Dead reckoning: uses an accelerometer, gyroscope and compass to calculate the speed of heading of the user. Needs to be initialized and calibrated regularly by another absolute positioning technique. Subject to drift so accuracy degrades quickly over time. Upside is its very cheap, no extra hardware or initial survey phase are needed.
UWB: very accurate techniques based on time of flight measurements. Requires expensive hardware for both transmitter and receiver. You can achieve cm accuracy with this but it's probably not what you're after
This is still an field of research so it's not that easy to find something that just works. I suggest contacting the IT department of your university, if they run a Cisco system, I know some of them provide some sort of positioning capabilities but I don't have much details.
As for your iPhone question, any app that accesses the private API to access Wifi measurements will be rejected by the App store, so you won't be able to publish anything that relies on Wifi. You can still use it for research purpose though, you'll just have to figure out the code yourself as there's no official documentation (some unofficial doc is out there though)
Good luck!
I'm familiar with CoreLocation, however, I need to design an application that shares the user's location across a shared network for business purposes. I wanted to know what would be the best way to transmit the user's Map Annotation to other devices on the shared network? Is GameKit/Bonjour the best place to start? Thank you for your help! ^_^
I'm afraid you did not provide enough information about your application needs. Anyway, you should read corresponding guides to have an idea about their limitations.
GameKit
http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/GameKit_Guide/GameKitConcepts/GameKitConcepts.html%23//apple_ref/doc/uid/TP40008304-CH100-SW18
There are some limitations:
GameKit is not available for Mac OS X (if you need it too)
There's maximum number of peers (client-server game is limited to 16 players)
Bonjour
FAQ - http://developer.apple.com/networking/bonjour/faq.html
Basically - Bonjour is here to help you identify services on your network. In other words, Bonjour can help you to find other devices with your application on the network, but it doesn't implement data transfer for you. You have to implement it on your own.
I would like to locate the iPhone in a building to build an application with similar features as the iPhone app of the American Museum of Natural History. There is no good GPS reception as there are also rooms in the cellar I would like to cover.
What can save me is that there is good wifi coverage in the whole area, so my idea was to triangulate the position based on the wifi base stations in range, whose positions are known. However I found no public API to find out which base stations are in range.
Questions
Do you have an idea how the app mentioned above manages to get the correct location indoors?
Could one add the wifi base stations manually to Apple's database and use the usual CoreLocation?
Do you have other ideas how to implement it?
Any help is very much appreciated!
Boundary conditions
The indoor navigation is only used during an event to guide guests new to the building, so no complex infrastructure should be installed.
There are approximately 14-18 rooms to be covered. They are in different parts of the building, so wiring everything up would be very costly.
The preferred solution would not require a server backend of any kind and would work with a list of wifi access points and their corresponding locations.
I wouldn't know about 1 and 2. But if you would implement such a thing, turn it around to save a lot of trouble: create your own free-of-charge wifi network, and let the network determine the location, either based on triangulation, or just based on the currently associated access point. Make their signal weak so you have one audible access point per room. Let the app ask a server in what room he appears to be. This will also work for any other mobile/pda/laptop.
As for other ideas: You could use bluetooth to do somewhat the same as you're planning for wifi. You can't do everything with bluetooth, but listing devices seems to be one possibility. So just put a bluetooth device in every room. Bluetooth range is limited by definition.
Another one would be to use the microphone in conjunction with a high pitched sound which identifies the room, but that would cause trouble with dogs (for blind people), attract bats, and repel mice at the same time. Better focus on an RF based solution ;-)
You can also check out Navizon's indoor positioning system:
http://www.navizon.com/product-navizon-indoor-triangulation-system
Their system is able to locate iPhones by using the WiFi signals transmitted by the device and doesn't require an app to run on the phone to locate it. It can locate any other WiFi enabled device for that matter.
Check out wirelesswerx.com They seem to be doing indoor location using Bluetooth and it looks like they can do permanent install or temporary for events.
Does anyone know what kind of range can you get from the iPhone
bluetooth? Also, would the connection be strictly one to one? I know you
can choose from a number of peers to connect to but once the connection
is established, it seems you can only transfer data between one peer? So
basically, is it possible to create some kind of "multiplayer" experience?
Just answering the range part of your question...
The 10 meter figure for class 2 devices (of which the iPhone is an example) is very much a guideline.
The range of a Bluetooth device is limited by many real world factors. The 2.4 GHz radio frequency used by Bluetooth is strongly absorbed by water. For example, consider an iPhone connected to a Bluetooth mono headset. If the headset is in one ear and the iPhone is in your trouser pocket on the opposite side of your body, then there's a lot of water between the two devices. This will often cause a significant amount of packet loss in practice (you can hear this in the audio being carried). So, in this case, the range is about one meter.
At the opposite extreme, two class 2 devices separated by nothing more than clear air can get ranges of hundreds of meters.
Other factors that influence things are:
Interference - Lots of things use 2.4 GHz. WiFi, for example can cause problems.
Antenna design - Space and cost constraints often mean that the antenna design is sub-optimal. I don't know how good the iPhone is in this respect.
Walls - Generally walls attenuate Bluetooth signals. However, sometimes they are useful reflectors.
Quality of hardware - Some chips work better than others. Even different firmware revisions of the same chip may perform differently. Different versions of the iPhone probably have (or will have) different chips in them.
Protocol - It is possible to work around poor signal quality with error correction and retransmission. Even if the iPhone SDK forces you to use a particular protocol, careful design of your application can make a difference.
So, in summary, you should probably do some real world tests.
The connection is one-to-one, but you can create an adhoc network with one of the phones acting as the master/coordinator. The other phones would route all their communication through the master/coordinator.
One device can theoretically connect to 7 devices. according to the master-slave role, the device can multiplex between each of them giving the user an impression that you are connected to all of them simultaneously. Bluetooth specification does not stop you from doing that.This is theory.
Now for the iphone, whether it can connect to to more than one device can only be answered by apple or someone who knows the iphone bluetooth API. But I am pretty sure the bluetooth chip inside iphone should be able to connect to more than one device.
Range is essentially going to be good enough for a normal sized room to be covered. It can be longer or shorter depending on environmental circumstances, but remember that bluetooth was created to implement short range connections.
A bluetooth device can be part of a piconet of eight devices, one master and up to seven slaves. The slaves cannot communicate with each other, they must talk through the master, think of a star topology with the master in the center. The iPhone SDK has a GameKit framework that can be used to create the network for multiplayer games. Go to developer.apple.com at look at the GKTank and GKRocket sample code to see how it's used. These games only support two players, but the GameKit framework supports more. Look at the app store and you will see games that have four or more players.
Hope this helps to get started.
Apple iPhone 3G has a Class 2 bluetooth module. Class 2 Bluetooth devices have a communication range of 10 meters.
At a given instance a device can connect to just one device because it follows a master/slave communication model. But still we can perform a multiplexing. So we can virtually connect to more than 1 device and by rapidly changing the connected device.
I found a good article here. It explains bluetooth very well.
According to the my knowledge, multicasting is not impossible with bluetooth. So gaining a multiplayer experience is NOT impossible.
The bluetooth in the iPhone is Class-2, with a 10-meter range, approximately.
Unfortunately I can't answer the other parts of your question.
One device can be connected up to 8 others. It all depends on the iPhone bluetooth API (which I don't know anything about), but with Bluetooth itself you could then send data to multiple devices.
I tether my iPhone to my laptop over bluetooth every day, and I seem to remember having done that at the same time as using a bluetooth headset. YMMV.
It’s the latest incarnation of Bluetooth, the wireless device-to-device technology that allows your phone to talk to headsets, car stereos, keyboards and other devices directly, without the need for a router or shared wireless network.