I'm writing an Android app that I would like to eventually port to iOS and Windows Mobile (though I know absolutely nothing about them right now). I'd like my app to be able to find other phones within a certain radius (maybe 20-30 feet) that also have the game installed so that the users can interact with others in their current physical space. Is this possible and, if so, how?
I plan on the app requiring an internet connection so my first thought was to use GPS like described at iOS Find Other Nearby Devices (GPS locations), but that would require continually transmitting data to the server to update the user's location using both bandwidth and battery (not to mention the server resources). GPS also seems to take a while to get any sort of accurate fix, and even though I wouldn't store historical data I wouldn't expect users to trust me with that sort of private information (as well they shouldn't!)
I know there are proprietary technologies, such as Sony's NFC, but that's far too narrow a focus to use for an app that I'd like to be device and OS agnostic. What other options are there? Assuming the user is willing to give the app the appropriate permissions, what other methods could allow one device to find another nearby one, within a 10-15 meter range, that is practical for a large (million+) userbase? Is HTML5 Geolocation a better path? Or is GPS my only real option?
I did find Use Android GPS to detect and connect with other phones, but was hoping the past few years have opened up further options.
UPDATE
Thank you for all the responses so far. To answer some questions posed in the comments and answers, I thought I'd describe how I expect the apps/devices to interact.
All users who install this app will have an agent running in the background to update their current geolocation and to listen for pings. Any user may open the full program and send a quick request for all other users nearby. If I go the central server route, then the server responds to that request with a list of nearby usernames. The user can then pick one of those to initiate a connection, in which case the target device makes a sound to notify of a request to connect.
From there it's easy enough to handle the interaction between two devices. Finding those nearby users is the sticking point for me.
Options I can see
Bluetooth (BT). I don't know, if I'm not too skeptical about it, but I see couple of problems. Short range. The biggest energy consumption. Maximum 7 peers connected at the same time (but maybe it's enough...). The big advantage is that a lot of devices support BT.
BT LE (low energy). Ok, it helps energy consumption problem. But, requires Android 4.3.
WiFi Direct (aka P2P). I gave it a shot, I'm a bit disappointed. The problem is that it needs Android 4.0 or higher. Even worse, some devices don't have required hardware. I launched WiFiDirectDemo from Android samples on Samsung Xperia Miro ST23i. Clicked on "search" and the only thing I got was a toast "enable WiFi P2P - in your settings". I clicked on everything in that settings, there is just normal WiFi and other stuff, no mention about Direct or P2P. Xperio Miro just doesn't support WiFi Direct.
WiFi connection with a server through internet + device geolocation. Server keeps positions of users and answers questions like "who is 20 feet in my range?". The problem can be the precision of geolocation. If the walls are thick or you are in a place on earth with few satellites - it can be very inaccurate.
To sum up
There is greater probability that somebody will have WiFi turned on all the time than BT. BT also have some time limits after which it is turned off (they make it this way to probably save battery). So, WiFi seems a better choice than BT.
If WiFi Direct is popular enough for you - I would give it a try. If not, option number 4 seems the best. It's not ideal, I know, but at this point it's hard to come with something better (we still need technology development, WiFi Direct looks promising).
I would use the central server approach. Each phone sends position data to the server. The server notifies the other users when they are in range. To limit used data, only send positions when the device reports movement more then X meters.
Also, consider using a Ping button. The user presses it to send the position when they wish to find someone nearby. Position data would only be sent on this ping. This would use very little power and provide good privacy.
It might be possible to detect details about the connected Wifi access point. If you could get the AP or Gateway's MAC address, you could send that as a kind of position. All the players on the same Gateway would be close by.
Related
I'm trying to figure out how I can send a notification to both phones when they reach a 6ft range from each other. I know that GPS is too wide of a range and so if wifi, I'm currently trying to use Bluetooth Low Energy because I heard it was more precise please let me know if there is any way I can go about this.
According to this blog, the signal range of each Bluetooth version varies. so it's difficult to find distance just by signal strength alone.
Solution: The proximity between the two devices can only be known when they are connected, as soon as they are connected request the user to stand 6 feet away from the other user and note the signal strength.
note: it won't be accurate. it totally depends on the environment
Here is a thread to find the signal strength. Hope this helps
I'm wanting to develop an app for my personal use so that several mobile devices can pair to several Bluetooth speakers (regardless of the brand).
Because the sync will take place through internet, and that the app may become cross-platform overtime, it is essential that I can give to the device which is synced to me the ability to manually tweak its Bluetooth latency (ms offset), so that the speakers can be in phase. That was achieved previously because I saw it in certain apps; yet I can't find any developer information about it!
Any ideas as to how one would go about developing it?
I don't think compensating for Android Bluetooth Latency using app side code only is possible, because the latency varies a lot by manufacturer.
It might be possible though if you can modify your speaker firmwares in order to add timestamp based syncing between your speakers... or use Wi-Fi speakers
For more developer information about Android Bluetooth Latency, read this:
https://www.soundguys.com/android-bluetooth-latency-22732/
I want to write an application that it can record the wifi hotspot's location we are accessing and display them in map. But the problem is - how do I get wifi hotspot's location?
I think I can use the wifi signal to get the wifi hotspot's location, but it may not be very accuracy at first time. And if there is no other solution, I could record the location of GPS when access wifi hotspot at the first time.
You'll not be able to find the hotspots location and you'll not be able to determine the direction and distance from your current position to the actual hotspot.
The hotspots don't report their coordinates (my wifi box doesn't even know it's own geographical coordinates). Google captured hotspots during their streetview missions and used the results to triangulate the positions of wifi hotspots and other companies did the same to build up databases.
So to get the information, you'll need access to a database that knows the coordinates of hotspots.
TL;DR
Such services (1, 2) and apps exist and you can just be downloaded and/or readily used.
Technical possibilities of localization
A very rough localization is possible via the IP address. This technically (and not always) only allows you to find the location of the ISP through which the internet is accessed, not the AP/hotspot itself (since a certain IP address pool is assigned to a given ISP). However, unless a VPN is used, that will usually at least tell you the country and often be even accurate to less than 50km (since ISPs are usually somewhat close to the internet access node). Many readily avaiable services are available for this, simply searching for something along the lines of "ip to location API free" should yield good results.
As you thought yourself, and as other answers already mentioned (in vague terms), there is however a better (or at least additional) option. You could just use the many devices out there to record the received WiFi signals and associate the strength of the signal with locations. With such a database, you could then in turn located devices, based on the received signals. Actually there are several such services, most prominently the one created by google and used (and fed with data by) pretty much any android phone out there. Fortunately, some of these are open and free to use (and contribute to), such as the one provided by mozilla, and another one.
Cell towers (and according databases) often allows localization down to tens or hundreds of meters.
In some places dedicated bluetooth APs are used to increase localization accuracy, especially indoors.
If you have a lot of time (several hours to days) and a more-or-less accurate time, you can also use the light (from sun and moon) to get a location. Even with the simplest means you can get down to a few dozen kilometers.
Watching the inclination of geomagnetic field against center of gravity in combination with an according dataset (very inaccurate, but cheap).
Of course dedicated satellite navigation systems such as GPS (~5m), BeiDou (10m~10cm), Galileo (1m~1cm), GLONASS (7~3m), where the lower numbers in the brackets are commercial/military only-systems. However, each of these require dedicated receivers.
These satellite navigation systems are often augmented by Ground Based Augmentation Systems (GBAS), which require additional receivers.
So now you can pick and chose for your application, which of these are most useful to you.
I don't think so. I use iPod touch maps and Samsung Galaxy Wonder as hotspot. iPod could tell my location! My guess is Samsung stealthily follow Apple's doing of communicate geo info through wi-fi.
Is it somehow possible in Android to get a count of all the nearby devices which are in active state(i.e. connected to any cellular network)? By that I mean any cellular device which is powered on and installed with a working sim.
The reason why I ask this is because whatever answers I have found so far suggest making use of bluetooth, wifi, nearby or some other custom app. My intention is to just look for devices which are actively connected to a cellular network. Each time I see a device emitting/receiving cellular signals the counter gets incremented.
I tried looking into the Android API as well but could not find something which provides this functionality. NeighboringCellInfo gives information about the device(and its network) on which the app is installed. And this is the closest I could get.
I was thinking that if I can get information about nearby cellular carriers then getting information about nearby cellular device should also be possible. End of the day it's about catching radio waves coming out of something.
Thank you so much for your valuable time. Really appreciate your help!
P.S. : I'm not very not sure if my question makes sense to you all. Please let me know if additional information is needed. I actually come from a totally different background and this is the first time i'm trying to develop a mobile app. Please feel free to correct me if my understanding is wrong.
I'm doing some work for my theses in networking, and have stumbled into a little problem. One of the first steps in the work I must do consists on having a computer working as an AP (I am using hostapd for this) and with it, detect all the devices in the room which currently have wifi turned on (do not need to be associated with any AP).
I have found a thread that pretty much asks the same ( discover mobil devices using wifi ), and I understand the answers that were given, but they don't give any hint as to how this can be done. The post ends saying that the person was able to do this using Kismet, however I can only seem to use Kismet to discover clients already associated with an AP.
Can someone point me in the right direction here please? If not using Kismet, then maybe suggest a different tool that works with Ubuntu.
Ps. I will need to run a continuous scan of the "room" to find any new devices and then send this information to an event manager written in Java.
I guess you could have a WiFi card, in monitor mode, scanning every channel for beacons. On Linux, aircrack-ng is the tool suite you are looking for. airodump-ng is the tool that shows you a list of devices present around your location. It is designed to display first the hotspots with the potentials clients, but also shows all the devices that are connected to an AP or trying to probe to an AP.
However, you won't be able to scan devices having their WiFi connection turned down. I'm not sure about devices not associated to an AP, my guess is you will be able to detect them if they send beacons one way or another (for example, to detect WiFi hotspots).
If you need this in Java, you can write a wrapper to airodump-ng, or you can launch airodump-ng as a service outputing to a file and read this file from a Java app.
No concrete answer I'm afraid, but I hope these will help you figure a way to solve your problem.