I am developing an p2p application in android for an educational project in which I want to form groups android phones of students nearby and exchange sensor data in a university campus.
Now there are some considerations :
Devices will automatically discover each other and upon discovering connect and exchange data.
The process runs for a long time maybe 4-8 hours per day. (process of periodically sensing data and exchanging )
Now the p2p groups can be formed using either Bluetooth or WiFi (Not WiFi Direct, simple UDP packets over WiFi considering phones are connected on campus WiFi).
What are pros and cons of using Bluetooth and WiFi in this scenario in terms of reliability, power usage of phones, scalability and any other you can suggest.
Among other answers and input, I would added this answer.
First of all, before we chose WiFi or Bluetooth we need to find out the difference between those two technologies.
I have made comparison chart that covers some of the important information you might need regarding your project.
Note: There are different versions of Bluetooth's and WiFi, this chart is to represent the the general picture of Standard Bluetooth,
Bluetooth v4 and WiFi. It is always suggested to refer to manufacture
specification of each technology.
From the chart we can conclude that Bluetooth has lower power consumption vs WiFi, but at the other hand WiFi has more bandwidth than Bluetooth.
Range in general is just approximation, a lot of things affecting range like human body, obstacles, location (inside or outside), if inside; structure type and materials used inside the building, noise from other sources and devices etc.
(*) Regarding scalability, I have tested WiFi and Bluetooth v4, both system with up to 8 devices, where one of those is host (group owner, server) device and 7 others are guest (clients). see the figure below.
What regards reliability, with Bluetooth v4 I have had some time connectivity problems, but when it works than every-thing is fine.
Note: Bluetooth v4 is not back compatible with older versions of Bluetooth, so if your host is Bluetooth v4 than all other clients
should have Bluetooth v4 or vice versa.
So I will not say which one is best, but if you need longer battery life and light data communication than Bluetooth is the way. Regardless if it is Bluetooth OR WiFi you might need to start with Bluetooth to and test it, if you are happy with it than keep it, otherwise switch to WiFi.
In case you want to build your own code, the code example I followed and used previously for another university research project. It is based on 8 phones (host and client) as seen in the figure above, we collected sensor information and send it to host phone using Bluetooth 4 connection. The source code we used for that can be found here. The same project has WiFi and other type of connections.
Android official google documentation has some information and code example regarding WiFi peer to peer connection, you can follow with example of the code as well.
Regarding collecting your sensor data and sending those to one device. You could added a method that starts collecting sensor or what ever data, and after connection is established successfully than start sending it over to the other device.
As others suggest https://developers.google.com/nearby is also a way to go.
As you can rely on campus Wifi, I would definitely go with the implementation of Google Nearby APIs in my App as it was designed for such use cases...
The way it works answers your question : it makes all the heavy stuff for you, including choice between wifi or Bluetooth for better performance...
Google Nearby is definitely a good choice. You don't have to tackle all the problems when working with WiFi or Bluetooth directly. But Google Nearby only works when both devices are online and have their screens on. For a more critical review of Nearby have a look at http://blog.p2pkit.io/how-google-nearby-really-works-and-what-else-it-does
If you can not accept these limitations, you should look into other frameworks like http://www.p2pkit.io.
Disclaimer: I work for Uepaa, developing p2pkit for Android and iOS.
Related
I am searching for some way that can connect to Bluetooth devices without pairing. Or at least make a connection first and then it does not need to be established all the time. Like how wearable devices work (i.e. mi band 6 or Huawei band 6). Can someone please guide me towards some helpful demo or documentation for this somewhere?
Also, I was wondering how was the security managed since my Bluetooth is always on to communicate to the wearable device. Though, turning off discoverability does not seem to create any issues in order to communicate with the device.
Most wearables nowadays use Bluetooth Low Energy (BLE), and with BLE you don't need to pair in order to exchange data - i.e. only a connection is needed. That being said, it is recommended to pair as the data exchanged between the wearable device and the phone will be encrypted, in addition to some other benefits in terms of privacy and security, Have a look at the links below that will go over connection/pairing in more detail:-
Should one create a bond with BLE device
The Ultimate Guide to Android Bluetooth Low Energy
Making Android BLE work
I'm actually working for a startup I'm building with two other founders. On the side I would like to develop a quick prototype to be able to deepdive into a subject I can use on my project : beacons.
Here is what I want to achieve : I want to be able to use a device as an emitter (using bluetooth, BLE, or wifi) and the other one to be able to know when it enters the first one range. I need that to be able to do indoor localization (just a check in system, not to know exactly where people are in that specific location).
I'm used to code mobile application with Ionic and I'm more a Javascript developer. I saw that there is already something which fit to my needs : Dazting which transform every device mobile as "a beacon" with either bluetooth or Wifi. Problem, I want to do it on my own but to be honest I don't really now how they manage to do that with Wifi. I know that there are some libraries to emit with BLE but what about bluetooth ?
Does it mean I'll have to code it with native code ?
This is what I want to achieve :
Coding an hybrid app (will loose less time and one app for every
platform)
Transforming the mobile device into an emitter : with bluetooth or
wifi
Be able to know the distance between a device which will emit and a
one that will receive the signal
I don't want to go with beacons : I'm not going to use macro-location and buying beacons for my project at the start is not something we would like to do.
Any ideas or suggestions on how did Datzing manage to reach that goal ?
Thanks in advance.
Datzing relies on emission of Bluetooth Classic, Bluetooth LE and WiFi packets from a mobile device that is made discoverable, either programmatically or through manual selection in settings. The unique MAC address or SSID of the device can then be used to tie the detected transmission to a registered "Beacon" on the Datzing system. Basically it just registers the unique identifier associated with a Bluetooth or WiFi transmission with the Datzing servers so they can have meaning.
Using this technology to transmit on an iOS device is severely limited due to operating system restrictions. Users essentially have to manually go to settings screens to start the emissions. Android devices are much more flexible if you have a native app granted the proper permissions.
On the detection side, iOS is also much more limited than Android due to the operating system blocking access to raw MAC addresses of bluetooth devices and preventing detecting SSIDs of WiFi access points unless the network is connected. As of Android 6.0, access to the raw MAC address is also restricted, making such a system work less well with Bluetooth on newer Android devices.
On both platforms, iOS and Android, the ability to use these techniques to the extent they are allowed by the operating system are possible with native code. Doing so with Ionic or Cordova would require cobbling together a number of plugins (if they even exist) to bridge to the native features to access WiFi SSIDs and do Bluetooth discovery and scanning. This is unlikely to be a quick protoype.
Word of caution: It is always a good idea to try out a system like Datzing before trying to reproduce it yourself, as limitations often cause technologies not to live up to the claims of the marketing materials.
I'm developing an app to communicate with a BLE device (Sensor puck from Silicon labs) and get whatever it is broadcasting.
I have NO experience in developing any sort of Bluetooth application using Android.
Do I need to manually pair it to the BLE device? I downloaded Sensor puck app from Play store, it automatically started to read from the device. I don't understand how since I didn't pair it.
Do I need specific API to communicate with the device? Is it like, I connect to the device and unpack the data which the device is broadcasting?
Any other information related to BLE application development would help.
Thank you.
PS: I can't use the app from the play store as I need the data from the device for some other processing.
I have a little experience with developing BLE apps.
Do I need to manually pair it to the BLE device?
I haven't encountered use case where I needed to pair mobile device with BLE device. Basically, you can communicate with BLE devices without pairing with them. BLE devices constantly emit signals and you can read these signals. Usually, from the emitted signals, you can read name of the device (or producer name), MAC address, RSSI signal from which you can compute distance from your mobile device to BLE device. Some BLE devices emit other information like temperature read from their sensors, etc. You can read information from more than one BLE device during the single scan.
Do I need specific API to communicate with the device?
Google provides API, which you can use to communicate with BLE devices. You can read more about it at: http://developer.android.com/guide/topics/connectivity/bluetooth-le.html. You can also use some third-party libraries allowing to communicate with BLE devices. Most of them are dedicated to so called Beacons, which are simple, tiny BLE devices.
Exemplary APIs for BLE Beacons:
Estimote
Kontakt.io
AltBeacon
ReactiveBeacons - this is open-source project, which I'm currently developing, so if you have any questions regarding it, you can ask me directly
Other projects:
Android Bluetooth Demo - this is very good and simple project, which can help you to understand how to use BLE API provided in Android SDK
Other information:
To communicate with BLE devices, of course, you need to have Bluetooth enabled on your device, but regardless of this permission, you also need to have Location enabled on your device and added location permission to your app. I guess it's done due to the fact, that you can use BLE devices for creating micro-location services.
I gathered some references concerning BLE for myself. You can check them here: https://github.com/pwittchen/ReactiveBeacons#references and maybe they will be useful for you as well.
Regards,
Piotr
it might be too late, but it also might be helpful for other users. So Sensor Puck works like a simple beacon and it doesn't require any pairing. You just have to scan all bluetooth devices nerby and verify received ScanRecord object. You don't have to use any specific libs or API, Anroid sdk contain all necessary api for such case (please see BluetoothAdapter startScan, startLeScan, etc). Also you can find an example how to parse raw data in my demo project https://github.com/alexeyosminin/sensor_puck_demo
Background
I have an idea for an app on vacation that needs to communicate to other phones with the same app. While on vacation those phones might not all have internet as roaming can be very expensive. The data is not a lot: like 500 kB max would suffice (in json).
Every phone has a bit of info that all the other phones would like to know, but if it helps the info can be stored on 1 phone (master phone from now on) and shared later to the other phones when back home over internet.
Phones
Android, iPhone and Windows Phone
We can't assume they have NFC, IR or zigbee. Just the hardware almost every phone has like bluetooth, camera, microphone etc.
My ideas
QR codes that changes, based on new info: If the first phone is scanned the second phones QR code has data from the 1st phone and itself and the 3rd phone has data from the 1st, 2nd and 3rd (itself) until it reaches that master phone that holds all data.
Data transmission trough sound that we can't hear (or we can). Con is that I don't know if something like this exists for mobile platforms and writing it is like a 3 year master thesis project.
http://nearbytes.com
https://applidium.com
https://developer.chirp.io/
Bluetooth. Can we connect like 8 devices? Would it work consistent (connecting even my headphones can be a hassle, what about 8 phones who try to connect simultaneously)
All of these ideas have big cons. Maybe I'm overlooking a better way.
I will add a bounty to the question for the best solution
An answer that explains it with a little bit of code reference (link is ok) is always better than just: "use bluetooth man"
TL;DR
The easiest (and most supported) way of getting multiple devices to connect to each other is using WiFi. Since your goal is to achieve data transfer with no internet, the most appealing solution would be to use a Peer-to-Peer network structure.
The two major smartphone OS's (Android and iOS) have API's and documentation on creating and transferring data over a Peer-to-Peer network.
Android WiFi P2P
Apple Multipeer Connectivity
These two also have a means to encrypt the data being transferred.
Windows doesn't seem to have an API to allow multiple peers connected, but their Proximity Class will work for one device at a time.
I can give a few outlines over the different options in each major OS:
Android
Android's WiFi P2P (peer-to-peer) API was created for transferring data without internet or another network.
From their documentation:
The Wi-Fi peer-to-peer (P2P) APIs allow applications to connect to nearby devices without needing to connect to a network or hotspot (Android's Wi-Fi P2P framework complies with the Wi-Fi Direct™ certification program). Wi-Fi P2P allows your application to quickly find and interact with nearby devices, at a range beyond the capabilities of Bluetooth.
Google even has Documentation and training on this API.
iOS
Apple's Multipeer Connectivity.
Very similar to Android's P2P API, they claim:
The Multipeer Connectivity framework provides support for discovering services provided by nearby iOS devices using infrastructure Wi-Fi networks, peer-to-peer Wi-Fi, and Bluetooth personal area networks and subsequently communicating with those services by sending message-based data, streaming data, and resources (such as files).
Here is a decent looking tutorial on using Multipeer Connectivity.
--EDIT--
Another iOS way of doing this, which is a bit of a mis-utilization(?) of the tool, is by using GameKit.
However, I think that to get it to work for your purposes might result in a bit of a hack, since the "players" have to be using Game Center.
Windows
The only way (apparently) to connect phones in Windows Phone, is by using Proximity, however, that only gives you the option of connecting no more than two phones together.
They state:
Proximity is a great way to create a shared app experience between two instances of your app running on two different devices.
Those are options in each of the major mobile device OS's.
App usage could be something like:
Decide which device was going to be the "master", so that other devices can connect to it. It isn't required to know this before deploying the app, but there should be a way for the user to decide whether he is going to be a client (receiving data) or the server (pushing data).
Once it was decided between the group of devices which was going to be pushing data, that device would have to be registered as the server (in the Android P2P API, you can establish a "group owner"), and then start looking for peers by initializing the service.
Then, once the devices are connected to the master device, you can start pushing data. An additional bonus is that when using Android WiFi P2P, all communication is encrypted with WPA2, and with iOS, you can enable encryption using MCEnableEncryption (however they state that is slows down data transfer rate).
Now you would just have to pick one method to go with, and make sure that all the phones ran that OS. Because these three methods of connectivity won't work together.
All of the three methods listed are done programmatically, so there should be no strange or odd things that your user will have to do. Searching for other devices, connecting, and transferring data can all be done within your app.
More help can be provided if the question is narrowed down to specific problems, but this should be enough data to get you started.
Don't try QR or sound. I think it would be very painful to transmit 500kb of data.
Bluetooth seems like a good solution but maybe, as you already said, hard to configure.
What do you think about wifi?
At least every Android and iPhone device can create a mobile wifi hotspot. By using this, you can easily setup a environment where 8 devices are in the same LAN (without using the internet by any of your devices).
Now your "master phone" runs a simple server to synchronize data (just like an internet server would do). Every of the seven clients could receive the ip adress of you master by scanning a simple QR code or sending a short message and afterwards configure itself accordingly.
Have you checked Alljoyn?
As quoted:
"Developers can write applications for interoperability regardless of transport layer, manufacturer, and without the need for Internet access"
You can create a Wifi connection between your devices. Than after connection it creates local network between your devices. Inside this network you, of course, can interact between your devices using TCP/IP connection. It works both on Android and iOS. Simply lauch your app as server on the one device
EDIT
Note, you have to connect your devices using any network. It is possible to connect the devices by initializing your device as WiFi-router. It can be both Android and iOS. If it is possible, you can connect your devices to any wifi connection.
Than, launch your app as Server-socket, the others as clients.
for Android (java) server use this link:
https://docs.oracle.com/javase/tutorial/networking/sockets/clientServer.html
try (
ServerSocket serverSocket = new ServerSocket(portNumber);
Socket clientSocket = serverSocket.accept();
PrintWriter out =
new PrintWriter(clientSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(
new InputStreamReader(clientSocket.getInputStream()));
) {
for android device client:
try (
Socket kkSocket = new Socket(hostName, portNumber);
PrintWriter out = new PrintWriter(kkSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(
new InputStreamReader(kkSocket.getInputStream()));
)
The same idea is for iOS (Objective-C):
server
https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/NetworkingTopics/Articles/UsingSocketsandSocketStreams.html#//apple_ref/doc/uid/CH73-SW8
and client:
https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/NetworkingTopics/Articles/UsingSocketsandSocketStreams.html#//apple_ref/doc/uid/CH73-SW4
A better way could be use Ble.
It's easiers to connect the phones because you don't need user confirmation.
Seems like you can connect up to 20 devices Maximum number of peripherals on CoreBluetooth?.
To transfer 500KB should require few minutes (may be between 2 and 5).
You can track an Android device without Internet via GPS.
Connection without The Internet:
SMS
USSD
DTMF (very slow)
How to design a tracking device on USSD is mentioned at
M2M IoT Cookbook
How to develop a device based on Wireless Wide Area Network modules
You also can use the Android phone as a data logger and store under the Micro SD Card and read the card by:
Replacing the SD card to your PC
Streaming the data local by Bluetooth
Forwarding the data at home by Wi-Fi
Or Possibly:
Your app can use SMS API to transmit the DATA or other SOURCES.
I made a google glass app which receives some data (wireless) from a laptop
and use the data to visualize something. The network connection is simple
UDP or TCP, but I noticed that google glass often miss some data and stop
visualization for a few or several second and continue.
So I'm wondering if Google Glass's wireless network connection is stable
and reliable. Did anyone experience similar or other network problem
with own apps (glassware)?
Thanks!
Not really. You cannot expect it to perform as your laptop or phone because instead of full-circuit card that supports 802.11 b/g/n with several antennas, Glass has only one wireless module on its board. That is from a Taiwanese company with module number WM-BN-BM-04 .
You can see the details about that module here or you can even buy it from Alibaba for $10 ;) . Thus in your case, you should minimize your data or use/implement an ACKing protocol. But a bigger problem about Glass Wifi is that it only supports WEP -hackable by high school students- and WPA/WPA2. No enterprise. You can have a WIFI connection at home but unfortunately not at university, work etc. So with this in mind, you should probably design only at-home applications with WIFI.