How to automatically detect and connect to usb device?

Question

I have an usb device (RF badge reader), and I need my application to detect for witch COM Port the device is plugged. what I`m doing now is like this:

    SerialPort mySerialPort = new SerialPort("COM3");
    mySerialPort.BaudRate = 9600;
    mySerialPort.Parity = Parity.None;
    mySerialPort.StopBits = StopBits.One;
    mySerialPort.DataBits = 8;
    mySerialPort.Handshake = Handshake.None;
    mySerialPort.Open();

If I connect the device to another USB port, the application crashes. Any Idea how to do this ?

Have you tried [this](http://stackoverflow.com/questions/5411454/detecting-usb-connection-c-sharp-net-cf-3-5?rq=1) or any other questions on stackoverflow? — BLaZuRE, May 26 '13 at 02:29
what if I have >1 devices connected to the computer ? how can I know what is the device I`m searching for ? — Ayman Bahouth, May 26 '13 at 02:34
From what I've looked up before while connecting to an Arduino, you would have to send to do a 3-way handshake in with every port to check if that's the device you want. But I didn't look too much into it. — BLaZuRE, May 26 '13 at 02:39

JeffRSon · Answer 1 · 2013-05-26T09:27:25.373

For most USB-Serial devices the COM port will change if you connect to another USB port. That's why it crashs when you try to open COM3.

Your best option is probably to make the COM port (COM3) a user configurable setting. You shouldn't disconnect/reconnect the USB device while it is used, so you actually don't need an auto detection.

You may, however, try to detect USB changes (find it on SO, for instance) and auto sense your device (involves a bit of communication). If you succeed or not may depend on the USB device driver.

How to automatically detect and connect to usb device?

1 Answers1