Phototransistor circuit to drive a counter

Discussion in 'The Projects Forum' started by gumpy, Apr 12, 2010.

  1. gumpy

    Thread Starter New Member

    Mar 27, 2010
    Hi all,

    Its Geoff here from Queensland Australia and a bit of a newbie.
    Needing a circuit description to do the following.
    What I have is a paper folding machine and when a sheet of paper enters, it breaks the light beam and sends a signal to the counter.
    The speed of the machine is governed by the size of the sheet the larger the sheet the slower the machine runs, maximum speed is 10,000 sheets per hour. The counter is a 7 segment 4 digit led, power supply 5V DC
    80mA, if it can run off the off the same power supply would be great.
    Please let me know if any more information is required.

  2. beenthere

    Retired Moderator

    Apr 20, 2004
    I can't suggest Aussie suppliers, but if you look at a Fairchild opto interrupter like the one in the Digi-Key catalog as their part #H21LTB, you will find it should work for your application.

    The fun will be finding a roughly equivalent part from somebody closer to home.
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
    I'm confused [normal] : What do you have on hand now?; & what do you wish to add. Do you need to add a speed control to the folder derived from the length of a paper sheet? Does folder have a speed control input?
  4. MMcLaren

    Well-Known Member

    Feb 14, 2010
    Hi Gumpy,

    If you need a non-microcontroller solution then you might consider something like the Maxim MAX7217 4-digit Up/Down Counter IC which includes drivers for a multiplexed 4-digit 7-segment display.

    Regards, Mike