C# – Windows Mobile – Device to Device via WiFi

bluetoothccommunicationwifiwindows-mobile

Are there any good api's or examples of communicating between two devices via WiFi?

I am programming an app for 600 window's mobile (version 5) devices. They occasionally will need to connect with another device and exchange info.

Each device connects to the internet via GPRS (using the phone line). I could do the communications via that, but it is slow and may not work in all locations (this app will be used nationwide).

Just as an FYI, I also plan to look into bluetooth, but the stack we get on our Symbol Devices (MC70) is the Stonestreet One stack (we cannot change that). It is a very difficult to use stack with no managed code API. Also, it requires manual setup to use. My users will not be very technically inclined.

If there is another way to communicate (ie via the WiFi connection) I would love that.

(Ideally, I would like to be able to programmatically turn on the WiFi, send/receive data and then turn off the WiFi (to save batteries).)

Any help/suggestions are appreciated.

Best Answer

Motorola (who have bought Symbol a few years ago) do release an Enterprise Mobility Developer Kit for .NET CF which also has some libraries for controlling the WLAN on a Symbol MC70. I have worked with this in the past and it seems to work very well. The SDK comes with the full documentation and some sample applications.

Related Solutions

C# – Windows Mobile – Serial Port Communications

The API help says,

By default, the ReadLine method will block until a line is received. If this behavior is undesirable, set the ReadTimeout property to any non-zero value to force the ReadLine method to throw a TimeoutException if a line is not available on the port.

... so, do that if you want to avoid it hanging.

Anyway:

How do you know that the two devices/ports are connected to each other (via Bluetooth)?
Are you setting the SerialPort properties (e.g. BaudRate etc.) before you call the Open method?
Does it make any difference which you invoke first, the ReadLine or the WriteLine? Instead of doing open/write/close and open/read/close, how about doing open/open/read/write/close/close instead?
What the receivers BytesToRead property return after the sender has invoked WriteLine?
Have you looked at the serial port sample code, which exists (according to the Stonestreet One Bluetooth SDK FAQ)

If their SDK does have a sample program, then I suggest you use it (unaltered) to verify your test setup (e.g. to verify that your devices are connecting properly), before you alter the sample program and/or before you test your own software (using the same devices/test setup which you've already tested with their sample software).

Android – Sniffing/logging your own Android Bluetooth traffic

Android 4.4 (Kit Kat) does have a new sniffing capability for Bluetooth. You should give it a try.

If you don’t own a sniffing device however, you aren’t necessarily out of luck. In many cases we can obtain positive results with a new feature introduced in Android 4.4: the ability to capture all Bluetooth HCI packets and save them to a file.

When the Analyst has finished populating the capture file by running the application being tested, he can pull the file generated by Android into the external storage of the device and analyze it (with Wireshark, for example).

Once this setting is activated, Android will save the packet capture to /sdcard/btsnoop_hci.log to be pulled by the analyst and inspected.

Type the following in case /sdcard/ is not the right path on your particular device:

adb shell echo \$EXTERNAL_STORAGE

We can then open a shell and pull the file: $adb pull /sdcard/btsnoop_hci.log and inspect it with Wireshark, just like a PCAP collected by sniffing WiFi traffic for example, so it is very simple and well supported:

[source]

You can enable this by going to Settings->Developer Options, then checking the box next to "Bluetooth HCI Snoop Log."

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