I have developed an application to transmit coordinates of one device to another and the distance between each is calculated. I wrote a java server and had been connecting both devices locally. However, now I want to test this over greater distances, in order to do so I need to connect one device to the external ip and use 3g in order to carry the device to over 500m.
I thought it might just have been a case of finding my external ip and putting that in where I had my local ip, however, there is no connection..I am still connecting the other device locally which is fine as there is no 3g on it anyway.
Does anyone have any ideas or suggestions as to what I need to do in this regard?
Thanks in advance,
Gary
Related
I am developing an app in which the first thing i need is how to get devices that are connected to my wifi network or same wifi network .ie ip adress,device name etc.
I don't have any idea how to do that have searched alot but there are no examples available.
I have done one thing that i will ping 255 ips and whichever will respond will be the connected ips but the problem here is that there are virtual ips already assigned to some websites so i need to detect only the real device ip addresses.
I want to do the same thing as done in the app WifiTalkie
Follow Any one of the following:
Way1:
If you mean you want to see all the devices connected to your current WiFi connection (and you are not trying to do Ad Hoc networking), then you are essentially wanting to run a network scanner.
There are a bunch of these around. This one has the source available on github
http://rorist.github.com/android-network-discovery/
Way2:
Refer How to detect all the Devices connected in a WiFi network from Android App
I'm developing a Java application which should listen on specific port on computer using Sockets.
The another app, which will run on Android device connected to the same WiFi, should find this computer with my Java program.
How can I find the computer in the network?
I've tried it in the small LAN (where are all devices connected to 192.168.*.*) using InetAddress.getByName(ipAddress).isReachable(); but in the bigger network (like eduroam or my school WiFi) I'm not able to scan whole network.
Is there another option how to connect two devices to each other apart from using Sockets and scanning whole network?
I'm not sure I understand your entire system requirements, but I'm thinking you could create a very small database at a hosting site (such as this) and have your PC periodically upload its private IP address to that database.
Then, when you need to connect to the PC on your android device, you query the database and determine the PC's current address, then connect to the device.
I have searched the web for this with no success.
This is my problem: I am developing an app that reads data from arduino connected with Ethernet shield.
I can connect to it on the internal network (home network) or through the Internet.
The problem is I need to know if the arduino is present on the local network and if not then look for it on the external ip address.
I have tried to use the ping function but it’s not working. Any help would be appreciated.
I presume you know the IP address of the arduino?, have you tried putting your pc\laptop onto the same subnet as the device, e.g. if the arduino has an IP address of 10.254.103.20 you could change the IP of your laptop\pc to 10.254.103.21 and then try pinging it?
Well for one thing, if your router supports NAT loopback (most do, but you may have to enable it) you can always just connect to the external IP address, regardless of whether you're on LAN or WAN.
Cheers,
Initially, ip-addresses from the ISP are always changing. I am working on an android app and I need to connect from outside my home to my internal network. I need a server connected to my modem/router and the server should save the public ip of my home network every time it changes.
Goal: make a communication between my android app and the modem/router.
My question is:
Do I have to program an app on the server side to do this job, or is there an app already available?
If none are available, could you please tell me the steps to create one, or any references to that end?
Thank you!
I think your best bet is to use a dynamic dns service. That will allow you to give your machine a string name, run the app they'll give you (or many routers support this built-in), and just reference the computer by name when you need it. See http://en.wikipedia.org/wiki/Dynamic_DNS
I need to make Android application which can send TCP queries to an embedded RS-232 system (connected to a router).
Unfortunately, no IP address was given because each embedded system has a different IP address.
To learn the IP Address, an android device (tablet/smartphone) must connect to the local wireless network and acquire the address of the embedded system. The local network also has a public IP address which enables the embedded system to communicate with the outside world.
My task is to send queries to the embedded system and get replies from it. The protocol is RS-232 for both input and output.
Please, give me an idea of where to start. Thank you.
Scan the network for the open port if there are no zero config options.
If you know the range of mac addresses the devices use you should be able to filter them out using ARP.
In case you can control both ends you can use multicast and save the discovery step.
Alternatively you can use dns-sd, but again the embedded system should be aware of it.
At the end, if none of the above options are possible you should scan the network as mentioned in other answer, but if DHCP is used you will never know if the address you obtained is still valid.
If you are talking about on the same network you could use a UDP broadcast which is picked up by the device which contains the remote ip, which then sends a response to the android handset with it's own tcp ip address.