I wasn't sure if this questions belongs here, but I'm completely new to this topic so hopefully you can help me out.
I have some kind of hardware which will be connected to my windows phone (wp7/wp8) through the audio jack. It sends some data in an audio format. I would like to retrieve this data through code. How can I do this?
Any source code or samples would be appreciated.
I wanted to post an answer so I could elaborate on my comment.
The problem with what you're trying to do is that the jack on Windows phones is an output jack. I haven't seen any that support microphone input. This means the jack is meant to generate a signal, but never to receive one. That means that you would never be able to attach a device and send audio data into the phone through that jack. It's completely missing any hardware that would allow you to interpret what you send into it, and honestly you risk frying the jack or worse, the phone itself.
Perhaps the best course of action would be to look at different ways to push that audio data into the phone. I can't really guide you on that because it's a very open course of action that depends on your specific needs.
Related
I want to capture live video of my Windows 7 computer, and later on have it streamed lived to a client to view as a livestream. Somewhere I heard that I could use C to make a virtual device and have the computer render the screen on that, and just output it through a socket. But, I've searched and I can't find any way to do this.
So what I'm looking for is maybe a tutorial or place to start with capturing live screen output and have it transmitted through the internet to a client that can view it live.
Any help is greatly appreciated :)
I have 2 WPF applications that communicate using a couple of duplex WCF services. I need to enable audio communication also between them. I've been looking for a solution for a while now, but couldn't find a good one.
What I've tried is audio streaming using Microsoft Expression Encoder on the "server" side (the one that feeds the audio), and playing it on the "client" using VLC .NET. It works, at least streaming a song, but it's a big resource eater. The initial buffering also takes a lot, and so is stopping the stream.
What other options do I have? I want a clear, lightweight audio conversation between the apps, kinda like Skype. Is this possible? Thanks
EDIT: I found NAudio and it looks like a good audio library, I managed to stream my microphone quite easily. However, I have big problem - I can hear the voice clearly on the client, but it echoes indefinitely. Plus, there's this annoying background sound (could this be caused by the processor?) and after a while, a very high, loud sound is played on the receiving end. All I can do is stop the whole transmission. I have no idea what's causing these problems. I use the 'SpeexChatCodec' as in the NetworkChat example provided (sampling rate: 8000, 2 channels). Any suggestions? Thanks
It would be a lot of work to write a library that would support that from scratch... if you can spend $150 on this I would suggest purchasing a library like iConf .NET Video Conferencing SDK from AvSpeed...
TL;DR available at the bottom
I've been trying to figure out a way to get two laptops (both running Ubuntu) to be able to pass basic messages back and forth without the need for them to be connected via a wireless network,either by an AP or ad-hoc. I want to reiterate here that ad-hoc networking is not what I'm looking for, I've seen many similar questions here with that as the answer.
I guess what I'm asking is: how do I achieve this? All I really need is for one computer to be able to send a packet, and then for another to pick it up via a packet sniffer of some kind.
Currently: I have both laptops in monitor mode (via a mon0 interface created from aircrack-ng's airmon-ng)so that they can sniff nearby traffic (with Wireshark, tcpdump,tcpcump.org's sample libpcap code, and opening a raw socket and just printing out all the packets. I tried each just because I thought one could be doing something differently/leaving something out). I also have a very basic program that consists of opening a raw socket to send crafted ethernet frames out to the air, but I can't get my two machines to see the other's packets. The sniffer running on each machine can only see the packets going out of that machine (in addition to nearby beacons/control traffic from wifi in the area).
Some things to note that might be important are:
-the packets I'm sending out appear in Wireshark (only on the sending machine) as malformed 802.11 packets (probably because I'm just filling them with junk data for now). I was under the impression that my other laptop would also see them as malformed packets, but it gets nothing
-the sockets I'm using are from a call to socket(PF_PACKET,SOCK_RAW,ETH_P_ALL). Raw sockets are something I just recently was aware of, so I could be misunderstanding how they work, but my impression is that I can craft a layer 2 packet by hand and ship out straight out to the wire/air.
If you're curious as to why I want to do something like this, it's part curiosity, part research for a project I'm working on. I want to streamline / automate the process of setting up an ad-hoc network, and what I'm trying to do here is for the laptops to do a small exchange to figure out the specifics of the adhoc network they are about to create and then make/join that network automatically, instead of either one person explicitly setting up the network OR having both people pre-decide the name, etc of the network and have both computers constantly trying to connect to that specific one.
I'm more interested if I'm going about this process in the right way rather than if my code works or not, if someone thinks me posting my (very basic, taken from another post on Stack Overflow) raw socket code will help, I can.
Edit: I am more than happy to post a complete set of code with instructions if I can get this working. I couldn't find much helpful info on this topic on the internet, and I'd love to put it up for future people trying to do the same thing.
TL;DR I want to send out a packet from one laptop and pick it up on another via a packent sniffer of some sort. No wifi network or ad-hoc network involved. Something akin to spoofing an AP's beacon frame (or similar) for the purpose of sending small amounts of data.
Edit 2:After some thought, perhaps what I'm looking for is some kind of raw 802.11 use? Having direct control of the wifi radio? Is such a thing possible?
I found out I was able to send packets out through my monitor mode interface as long as I had correct 802.11 with radiotap headers. I think the problem I was originally experiencing (not being able to sniff the packets) was because they were malformed and thus not actually getting sent out.
I was able to accomplish this by adapting the example code found here, courtesy of someone named Evan Jones, except I did not need to use an Atheros based card or Madwifi drivers, everything worked fine with the mon0 interface created with aircrack-ng.
I am certain that Apple Mac do this. Apple call it 'bonjour'. There may well be a proper IETF spec for it. This is an Article on Bonjour this is Wikipedia on an open component of bonjour which might help get you moving.
Hi guys
I'm working on this project where I'll need to retrieve information from a database through sms/ussd, much like how you would check you credit on you mobile phone.
Would appreciate any help to head me in the right direction.
(Hope I put my question out clearly, if not ask me so I can clarify)
I can help you extensively in solving your problem. As far as I got understood what you want to achieve is, perhaps that when a SMS message comes to your GSM Modem or GSM Phone, your software should be capable enough to interpret that message according to your protocol and should respond accordingly, also when it needs to process database. This is absolutely possible. Let me describe it in brief. Following are the general steps:
You must connect your GSM Phone or Modem through your software with a particular COM port.
After assigning and configuring the port, You issue AT+CNMI=2,2,0,0,0 command to Modem, if it responds to OK, then it indicates that it supports this command, else an error is generated.
Now send an SMS from some other phone, you will see that the SMS directly goes to your software, now you can process it as per your needs.
The whole process is slightly a lengthy description, but it is possible.
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I am looking to develop an application usable on the devices of visitors so that I can tell where they are. The initial idea I had, already done in some museums, is to have a number on specific locations within the museum, they call a phone number, enter that number, and get enhanced content, perhaps audio narration about that space. This is nicely device agnostic, though some WiFi only devices may not have a mechanism to call a phone number, but perhaps having folks on WiFi load a mobile website and choose their location (assuming the number of spots is not too many) from a list, and then click a button.
I'm new to this, and have been brainstorming on this, but I really don't know what I don't know. So here are my questions:
Can I use GPS indoors and get accurate information or will that basically not work in most buildings?
If I use a service like Skyhook Wireless, and use multiple WiFi routers, will I be able to locate the WiFi connected users accurately?
Can I use Bluetooth somehow? Setup for Bluetooth seems like a hassle, but maybe there's a Bluetooth mode that is simpler to use for an application like this?
For devices with a camera, what can I do with an image here. Photo of a QR Code? Are QR code reading libraries built into devices I can use, or would I need to find a library?
Are there are other techniques I might be able to use, maybe counting footsteps with the accelerometer somehow? Or using magnets somehow for devices with a compass?
Suggestions welcome, assume I'm trying to target as many smartphones as practical (Android, iOS, Blackberry, webOS, Windows Phone 7) that are popular in North America. If there is a way to also include devices that are not considered smartphones, that would be great too.
UPDATE
Why indoor navigation is so hard: Your phone can get you to the museum, but it can't guide you to the T-Rex by Nick Farina
UPDATE 2
Brooklyn Museum experiment with QR Codes: too soon to
tell/negative
Very few people can successfully scan and use a QR code
UPDATE 3
Think GPS is cool? IPS will blow your mind
QR codes are your best bet. They're cheap and, for example, in a museum you could put one next to every painting. For devices without a camera, you could choose to print a location-code next to the QR that they could enter manually in an app. Here's another solution as well:
Set up a wifi repeater/booster in each location you want to determine (ex: in a museum, each room) and record the SSID for each router. As the user walks from each room to the next, their device will automatically switch to the repeater with the highest quality signal (the one in that room). Simply have your application test for which SSID the user is connected to.
GPS is not accurate enough and may not work inside buildings and Skyhook wireless is only for one address. Having users call a number and/or go to a website to manually select a location is too many steps for the user, and the user may not have reception to place a call. Bluetooth is a huge hassle.
Can I use GPS indoors and get accurate
information or will that basically not
work in most buildings?
no, GPS needs a clear view of the sky. regardless, the accuracy of GPS is around +/- 50 feet and can be worse.
If I use a service like Skyhook
Wireless, and use multiple WiFi
routers, will I be able to locate the
WiFi connected users accurately?
aGPS is less accurate than GPS.
Can I use Bluetooth somehow?
bluetooth is not location aware.
android 2.3 introduces something called near-field communications. this would theoretically allow the person to wave their phone over a receiver and transmit information. it's quite new and i think the nexus s is the only device with hardware support for this. at best you are looking at some early adopter pain for that one.
Photo of a QR Code? Are QR code
reading libraries built into devices I
can use, or would I need to find a
library?
that's a good idea. QR codes are popular because they are simple. libraries are not part of the SDK but they exist. it would be hard to build one yourself if it came down to that. by the same token, you could just as the user to enter a simple location code. essentially the same thing and might be simpler than aligning the camera for a QR read.
it does depend on your application. if you want this to automatically locate everyone without an user intervention, QR codes / codes won't work because the user has to take some action. even NFC, from what i've read, operates on very short distances so the person would need to wave the phone across something closely not just walk by.
If you're talking indoors, I think you have some great ideas. GPS may be spotty depending on the building, and Wi-Fi triangulation only works if your signal is proportional to the proximity of the user to the unit. Here is my suggestion:
QR Codes sounds like the best option here if you don't mind having them all over the place. If someone can scan a QR code, (which they are on most all platforms, it's just making sure your users have a decoder installed and can actually use it), then you have three things going for you:
You know they have to be in range to scan it...so that's far more accurate than you can get with other location devices.
you can use the QR code to embed a link to a download site or embed the actual information into the QR code if it's not too much.
Most smartphones today have QR code scanner apps built in, and there are libraries (java and .net) that you could use to build your own app.
The downside here of course is that you're assuming the cameras are good enough quality and that someone isn't going to deface your QR code so that subsequent visitors can't read it.
Keep in mind the bump application. They don't use bluetooth or any form of wireless technique to determine if two people are near each other. http://bu.mp/faq
Since you have 1 building that you care about. Why not simply have a root device or network of devices in your building that you care about. This root device would communicate with all the clients to do your bidding.
Maybe cellphones can´t solve your problem, have you considered cameras on each room and a QR code tag on each guest? you might get the images from the security camera since they are infrared. Another way of achieving this is by locating the camera in front of the door so that the guests are always seen by the QR code algorithm.
Cellphones are just too diverse to implement this, have you thought that the guests might not have a cellphone at all?