I have been tirelessly trying to decide on the best option for getting phones to talk to each other that are nearby, I need something with the ability to broadcast and receive. It is kind of like NFC with more range, I'd like to be able to send messages 30 to 50 feet away using nothing but a phone.
Bluetooth cannot broadcast and receive to more than 8 devices still, there might be changes to that in Apple's new OS but Android and Windows are still going to be lacking, so Bluetooth is out of the question.
I was thinking of maybe trying to use Wifi, but I have not found very many good resources on how I would go about doing that without making a virtual server, I'd much rather not go that route if possible.
I could even use GPS although with the power consumption of GPS and having to be an always on feature I am not certain I would like to use GPS if I can avoid it.
The one I really want to use, uses sounds made and received by the phone. I have been playing around with a listener that converts different frequencies to 1's and 0's, but with all things sound, it gets increasingly hard if lots of people are talking, or there is music playing, or if there are objects in the way, the Doppler effect and more. Is there someone out there who has already made a filter for this? Some other problems would be, what is the range sound travels at 20khz through air? I can also not find much good documentation anywhere for devices whose speakers can make sound above 20khz but it seems most can, the problem then is what microphones can hear sounds above 20khz.
I would really love to use sound as I think it is interesting, and it would make the app work without any internet or phone connection which I think is pretty cool. This is a side-project I am working on, and really don't want to spend hours down a path that will ultimately fail.
If anyone thinks it's possible to do this with sound over other devices, I'd much rather like to do it that way, I think there is a lot of interesting things you could do with that technology, I just don't know how viable it is over using wifi or bluetooth or even GPS.
At ios you have no controll to low level "things". You can read the current connected wlan ssid, but not all wlan ids which the operation system can see.
I would first try the location services approach. Settig to 1000m acuarcy will usually disable GPS, but enable cell-tower an wlan locationing.
Especially the wlan locationing gives an indirect hint that the persons are near the same wlan
Related
I was always wonder what would it be my first question on StackOverflow since everything I'm looking for is already asked. (Find only one similar here Bluetooth data transfer between two countries )
BACKGROUND STORY:
From when it comes I’m a fan of Nokia N-GAGE. It’s a Nokia’s phone from 2003 with dedicated games. In its heyday 2003-2007, it has single-player, multi-player via Bluetooth and using a dedicated internet service N-GAGE ARENA for compete with people all over world.
N-GAGE ARENA servers were disabled about 2008 and as far i understand It isn't even worth trying to resurrect such a infrastructure. Mainly because it requires modifying the code of each game and that's illegal.
Multiplayer mode using Bluetooth work fine, but requires opponent 5m away max.
Nokia sold 1mln copy of this phone, and still are people all over world collecting n-gage games. I have a dream, I want to reactivate the possibility of playing multiplayer with people from all over the world.
PROBLEM DESCRIPTION:
I want to use the Bluetooth multiplayer mode by extending the usual N-GAGE to N-GAGE Bluetooth connection with an additional 3 elements. Two N-GAGEs, instead of connecting directly to each other as host-join, connect via a PC / smartphone applications that communicates with the server that transmits full data sent from the game of one user to game of the opponent.
I admit that I do not have full knowledge of technical limitations. In my opinion, as a software engineer, it is theoretically possible, but I want to consult you, people more familiar with the subject. Maybe someone is working on a similar project and can comment.
WHAT DO I KNOW:
The application would have to transmit all data from the Bluetooth connection so as not to disturb the illusion of a direct connection between N-GAGEs.
The application must enable the selection of an opponent on the basis of the game. The choice itself could be made on the basis of some kind of chat in which users first define what they are playing, who’s the host, and then the connection is made.
WHAT DO I WANT TO KNOW:
Does what I describe is even possible?
Is such capturing Bluetooth connection and forwarding is even possible?
Does the development of technology in these 15 years allow me to transfer Bluetooth connection real time through 2 additional devices and Internet connection?
I WOULD BE GREATFUL FOR:
Any technical tips, literature that can help me to understand my limitations.
Any constructive criticism. Of course before I start doing such a project I have to confirm that isn't a utopia. For me It’s a side project, I’m able to spend years on it, but don’t want to get to dead end after all effort.
Does what I describe is even possible?
Yes, yes it does. Your hardest part will be setting up a tranceiver to interpret the I/O. Your failure point would be super-encrypted messages and making transmission difficult...
If it's clear I/O you can signal this through any server and output it back to the tranciever to output. Confusing but possible just not sure of the design or how bluetooth sends its data.
Is such capturing Bluetooth connection and forwarding is even possible?
If a connection is possible then forwarding it is too. Considering this piping the transports.
Does the development of technology in these 15 years allow me to transfer Bluetooth connection real time through 2 additional devices and Internet connection?
Bluetooth real-time no... with added network latency, you're looking at anything from 1-200ms~. you may be able to improve it?
Overall I think if you can:
Connect the device to PC, and have PC talk back to device through blue-tooth
Read the data that goes in and out
Encryption proves little or none at all to be able to signal the data properly, tricky to explain you'll know though if there's a wall.
All should be possible it doesn't overly go against the grains but do more homework this is very valid.
I'm working on a project to track delivery trucks leaving and returning to the office.
While I know RFID would work, we're also looking at BlueTooth with mobile apps. Ideally, once a driver installs the app, we register a unique ID for the device, and a BT reader identifies when phones/deliveries leave and enter range without any user interaction.
From the Android 6.0 release notes, it looks like the MAC address is hidden from apps and BT broadcasting. https://developer.android.com/about/versions/marshmallow/android-6.0-changes#behavior-hardware-id
User management of app installs and enabling BT aside, is this feasible?
Can someone point me in the right direction to confirm what identifiers are available?
When I understand you correctly you actually do not want to track where a phone is but want to know if a person/truck/phone passes a kind of checkpoint or gate?
For newer smart phones you cannot rely on the visible MAC. Bluetooth classic is usually not visible and the BLE MAC is randomized as long as the device is not paired and bonded.
Indeed as PaulW11 stated, the simple way would be to implement an app which does BLE advertising with short advertising interval. Inside this advertisment you can put some custom data. This will be visible to everyone. This ID can be some random number, a number assigned by you or whatever.
At the gate you would implement a BLE scanner grabbing all advertisments near to it.
This should be easy to implement.
I would also like to mention the drawbacks here: If someone passes the gate you may miss him. BLE with Android is always tricky and you might have the situation that the bluetooth subsystem on a phone may have stopped working or so.
One the other hand if someone comes accidently near to your gate, you will think he left or returned. Near can be something around 50 m or so with good conditions or only 10 in other cases.
And even worse: If someone stays 'nearly' in the range of the gate you will see im sporadically. This may confuse your come and go logic if he is visible every 3 minutes or so...
So I'm kinda stuck here.
I have a radio station, but we are mobile. So I have a studio on wheels. The problem is, we have an antenna, but we always have to place that really close to our studio. Now I want to make an device that can stream the audio from the audio mixer to the internet and can be received by another device in another network and send that signal to the antenna (audio output).
to make this clear, I made a schema with raspberry pi's;
I want this to be plug and play So I only have to plug in the device in the modem (or network we have) on both sides and the devices should find each other.
I don't know HOW I can do this, so I need to know a couple of things:
What hardware should I use?
What software should I use?
What is the best configuration to accomplish this?
Can I use 2 raspberry pi's?
How can I let the devices find each other over the internet?
There need to be some features;
The system needs to be able to buffer the audio for 5-10 seconds
It needs to be direct, so it's live and not a file that needs to be played
The system must be failless (beside the fact the internet can die).
Plug and play is a must, I don't want to have a really messy configuration to do. (if possible, without any kind of portforwarding).
I would really appreciate help and a decent explaination.
regards,
Robin
Well, it depends on your capabilities as a programmer.
If you're really fixated on the RPi for it's convenient form factor, there's a ton of community support, so I'd start with something like this project to kick start you in the right direction. If you already know python pretty well, modify away and have fun.
If you have no programming experience, you'll probably want to put a desktop in place of the RPi and launch some instances of VLC. It's not necessarily plug n play, but you can get close enough by getting a command line VLC to launch at startup.
Either way, the more difficult problem here is the "over the internet" part. This would really need to be a server-client model, but who is your server depends on who is more stationary (I'm guessing Location 2?) because the client will need to know the IP address of the server somehow. There are dozens of ways to make this happen, but at the end of the day, you'll want to use sockets accomplish the
It needs to be direct, so it's live and not a file
... which unfortunately gets complicated. See this answer for confirmation. Would love to help with some tips on implementation, but we need more information about your willingness to "dig into the code", the necessity of the RPi, and whether the stationary location has a static web address.
I am working on a project where I need to attach a sensor to the computer like laser sensor or an infrared sensor, to use in a foul line detection. Basically the idea is, if someone steps on the foul line, the laser or infrared will be blocked by person's foot, and the laser/infrared won't be received by the receiver, causing the sensor to send a signal to the computer.
The problem is, I don't know where to start something like this. How would I go about attaching a sensor to a normal computer (like a normal PC that we use)? If someone could direct me into a direction or has any inputs, that would be really appreciated. Thanks a lot!
You may want to look at Arduino (http://www.arduino.cc/). It is an open-source microcontroller that can be used along with a computer and is designed to be hooked up to various types of sensors. It also has an extremely helpful, active support community.
There are several approaches to the task of bringing the sensor signal into a PC (to take advantage of PC's computing power, good user interface, connectivity to the web).
Look for integrated sensors that have an interface for attaching to a PC (RS-232, USB, Ethernet). For example, you may find something useful by googling photodetector USB.
There are I/O (input/output) devices for PC. They have analog and digital inputs and outputs. Look up LabJack, National Instruments USB-6008 and dozen other types of commercial USB I/O boxes.
Connect sensors to a microcontroller (uC), then connect uC to the PC through a USB or RS-232 or Bluetooth (the list goes on). This involves more hardware. You'll need to write firmware for the microcontroller too.
Obviously, which approach to choose depends on your skills (or willingness to acquire new ones), timing, budget, team structure (if it's a team effort).
You could use a photo-transistor and a Yocto-Knob. The Yocto-knob is an USB device able to quickly detect resistivity changes, you just have to connect the photo-transistor to it. Here is an application which looks pretty similar to yours: they use a light barrier to detect and photograph a fast object:
http://www.yoctopuce.com/EN/article/how-to-drive-a-camera-shutter-automatically
which API or library on which mobile OS is to be used when one needs to write a code to use the phone's IrDA to create the necessary impulses to remote control consumer electronics e.g. a HDD media player?
Is maybe a certain mobile OS better suited for that kind of application than others?
First you need to know that IrDA is not the best choice for remote control. It can be done, but IrDA is by design high speed/low range, you can emulate low speeds but ranges (IMO) are far from practical usage (Nokia e50 is able to control digital camera shutter from 2-3m... with very, very careful aiming). The amount of hacking needed to achieve this is shown here, you basically need to trick IrDA to send correct impulses with correct frequency.
The second thing is that CIR remote control is not as simple as you might think. There are countless standards that differ in used frequency, modulation, wavelength, command codes and so on. You need to know what you want to support. LIRC site can be very helpful in determining that http://lirc.sourceforge.net/remotes/. Approachable explanation of what it all means is available here: http://www.sbprojects.com/knowledge/ir/ir.htm
As for ready made libraries and platforms... I honestly don't know. I've seen it done on PocketPC (nevo among others) and Symbian S60 (irRemote). Haven't seen working J2ME app yet.
Last time I needed the IR remote I hacked it together using IR diode, AVR ATTiny and surprisingly short piece of assembly :)