Qt integration with finger print scanner

  • Hi all,
    I am a newbie in -QT- Qt, I have been working on a project where in we are using -QT- Qt as a GUI frame work. I have to work on finger print scanning and the scanned image should be displayed on the display and also the GUI should respond,navigate and show messages on the display while using the device for eg : "Please put you right index finger on the scanner" and once the device scans the image, a message should be displayed that "Your image is captured successfully" etc etc.
    Can anyone let me know how to do this?

    I appreciate any help and suggestions.


  • Have you determined which hardware you are going to use and what sort of API's it provides for reading information from the device.

  • What step of the process do you have a problem with? You will have to ask a bit more specified question. Do you have problems with the actual finger print reading (not supported by Qt, you are on your own there), or do you have problems with the UI design?

  • Thanks for your reply..

    I am using the ARM 9 controller and linux os.The finger print scanner IC is SUPREMA 3030 and it provides the API's for Enroll by scan,enroll by image,reset etc.

    I have the Qt screens ready and also the finger print scanner is working fine for the commands I am sending through the serial port.The Qt supports this finger print scanner. My doubt is, as to how to integrate Qt application(screen) with the Finger print scanner.



  • So you are able to send commands to the scanner from the Qt application or is that you are facing problem in doing so. Its still not clear where you are facing the problem in integration.

  • Thanks for your quick reply..

    I am facing the problem in sending the commands from the
    Qt application.

  • If you have problems with serial communication, what are you using to do that? Do you use QExtSerialPort or a class like that?

  • I have no idea as to how to do it. I am very much new to Qt.
    The things which are done is:

    1)I have developed an application where in I am sending the commands through serial port and the scanner is responding to those commands,

    2)I have a set of screens which are developed in Qt for display messages like "Please put your right finger" etc.

    My task is :

    When the device is on and it display a message to Put the finger. Once the user puts his finger on the scanner and image is scanned, it should be displayed as "The finger print enrollment is done"

    Ultimately,I want to know how the Qt application is calling the finger print commands and is navigating to the next screen.


  • If you already have an application that does the communication, then perhaps you can interface with that application? Is that application that you have a command line application, or something else?

  • I want to know how to interface qt application with finger print application so that when I use the device the finger print scanner and qt application will work synchronously.

  • I do not think your problem is Qt related, really. Your question is very general; too general to really answer. What you are asking is how to synchronize an unspecified application with some piece of hardware that almost nobody here will be familiar with. What kind of answer do you expect?

    I would imagine that the scanner has a serial interface that allows you to query its status and that will allow you to give it commands to do something. So, you would need to build some kind of class that you can use from your application to encapsulate that. I have no idea how complicated the state diagram you are dealing with is, so a ready made solution I do not have for you. You could considder a simple class to reflect and manipulate the state of the scanner with some appropriate signals and slots to manipulate them, or you could go for a complete state machine. It depends on your needs an how complicated the hardware is to work with (which I do not know). The point is: your class provides an interface to give commands to the scanner, and to receive status updates from it. You can change the visual feedback to the user based on these signals.

    Internally, such a class could use QExtSerialPort or some other serial port abstraction class to facilitate the actual communication with the device.

    Based on the information you have provided so far, this is the best I can do for an answer.

  • Thanks a lot for your reply..

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