7 segment data to RS232

Discussion in 'The Projects Forum' started by volvomiro, Jul 23, 2009.

  1. volvomiro

    Thread Starter New Member

    Jul 23, 2009
    I am new to all this, please help.

    I have a factory device which displays values on 7 segment displays. I have the access to all pins and the electronic interior of the device. How can I get the values out from those 7-digit displays to i.e. HyperTerminal via RS232?

    Is there a way to binary decode values with some kind of device that would connect directly to displays' pins?

    The device already have a RS232 connection and it sends the info directly to the PC into HyperTerminalm but I need the data from other displays that I have mentioned.

    This solution all together would be a reverse from common driving the values TO the display.

    I deeply appreciate all the help I can get
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Welcome to AAC.

    Your post was tacked onto a year old thread that had nothing to do with your question. We prefer that you not hijack threads, but start a new thread for each new question.

    What is the device? Does it have a schematic?
  3. bertus


    Apr 5, 2008
  4. lightingman

    Senior Member

    Apr 19, 2007

    It all depends on the way the 7 segment displays are driven. If they are driven straight (no multiplexing), and driven by a decoder like the 7447 or 4511,then it would be quite straight forward to take the data from the input of the decoders (4 bits per digit) and read them into a PIC Micro. You can then convert the data and send it serially through something like a MAX232 driver.

    If the display is multiplexed, it would need a bit more programming to sort out the timing to clock in the data (one digit at a time) before the PIC sends the serial info.

    The segments can be read directly from the displays depending on how many digits need to be read, and if there are enough inputs on the PIC to do it.

    Just a question:- How many digits?

    It can be done though, it is not that difficult.

    Last edited: Jul 23, 2009
  5. lightingman

    Senior Member

    Apr 19, 2007

    Just read the anode or cathode of each display (whatever way round it may be), and then read the 7 segments each time the display is selected (14 inputs required and maybe one for decimal point if used) and one output for the serial output. A PIC 16F876 would do the trick, and if you wanted to add a dip switch to configure the serial data (baud rate, parity and bits), you do this as well.