Discussion in 'The Projects Forum' started by djstar, Feb 7, 2011.

  1. djstar

    Thread Starter Active Member

    Jan 26, 2008
    Hi , i am building a electronic dice for a college project that displays a number on a 7 segment led when a button is depressed. When the button is held down the counter is enabled and the 7 seg will display the numbers 1-6 and loop back around. when the button is depressed it displays a number.

    ive had a idea of adding audio to the dice so that when a number is displayed it will call out the number. I’ve found an ic that has 8 memroy banks, i will be using 6 locations to store each number. The problem im having is how to link the audio ic to the dice. one idea i came up with is to use the output from the bcd counter and connect that to a demultiplexer so that when the bcd outputs a binary number the demux will select the correct output wich will switch on the correct number memory bank on the audio ic. The input has to go low for the audio to be be played on the memory bank.

    The problem that im having is that when you hold the button down. it will continually count from 1-6 untill the button is released. so this will constantly play each audio bank. i was thinking of having some sort of delay so that a retrigerable monostable is conntected to the outputs of the bcd and keeps re setting untill the button is depressed and the then the monstable will then carry on and charge a capacitor up to 0.7 and switch on a transistor which is connected to the enable.

    I hope you get the jist of what im after. if theres any easier way of linking the audio to the display will muchly be appreciated.
  2. Bernard


    Aug 7, 2008
    What would happen if input switch was also connected to one of the 74138 enable pins? Would not the 74138 be disabled while the BCD was counting; when finger was lifted, BCD stops counting, 74138 decodes last no., speaker sounds appropriate tune.
  3. thatoneguy


    Feb 19, 2009
    From the APR9600 datasheet, for playback, /CE (Enable) needs to go low and /RE (Record) needs to go high, in addition to the input of the data.

    Using the blanking input on the 4511 or other 7 segment decoder would prevent the numbers from blurring past during the count.

    Were you going to have an off/on switch, or were you trying to build this with only one button?