Digital Counter

Discussion in 'The Projects Forum' started by mkv, Nov 28, 2009.

  1. mkv

    Thread Starter New Member

    May 17, 2009
    Hey there,

    Ive got a digital counter that I have been using to well, count things

    I needed one that could count a fairly high number of hz, so I went with this:

    Worked great and did exactly what it needed to, until the LCD cracked

    I would prefer not to buy another one, and I dont think I can just get another LCD to replace the broken one, so I decided I would attempt to rewire several 7 segment LCD (or LED) displays to it to do what I wanted.

    I only need 4 digits, and for its application, it is actually more convenient for the display to be further away from the circuit board anyways.

    However, when I went and got the voltage across the ground and annode for the display of the thing... its only .2 V. I cannot find any display that will run on under 2V. Does anyone know of anywhere I can get something that will display for such a low voltage?

    Or is there any --easy-- way to make it work with a higher voltage 7 segment display (I can think of a few ways, but by the time i finish them i might as well just buy a new counter (cost wise anyways)

    Thanks for your help-
  2. SgtWookie


    Jul 17, 2007
    Sorry your display cracked; that sucks. Never heard of that happening to an LCD display unless they were dropped or subjected to some external force.

    Anyway, you would likely be much better off to replace the existing LCD with another LCD. All of the voltages necessary for an LCD display should be there, just slap in another and you'll be GTG - once you figure out what all of the pins are.

    LCD's have unique drive requirements. You will probably find an excitation signal on the original signal lines that measure about +/- 15v to keep the screen going. The digits require very low current.

    If you're going to change over to LED 7-segment, you will need a lot more current than the LCD drivers will be able to provide. I suggest that the attempt may be fruitful, but the road will be long and full of land mines.

    Better to try to find a similar type display. At least most of the necessary voltages will be present.
  3. Wendy


    Mar 24, 2008
    Have you gone through Grainger, McMaster Carr, and other common industrial outlets online catalogs?

    There is also an online version of the Thomas Register, which can help you locate a manufacturer. Once you have them, you can find out who sells their stuff.
  4. mkv

    Thread Starter New Member

    May 17, 2009
    The fact that it cracked was entirely my fault. It is being used as a counter for a paintball gun, and took a hit straight on from a 68 cal paintball going at roughly 250 fps... so the fact that it did crack wasn't entirely surprising, that is why I would like to try and separate it from the board so I can use the spare room to add a piece of plexiglas in front to stop future incidents lol

    I originally bought the piece through digikey, and can find no mention of the pieces that make it up. Maybe I'll try to contact the company that makes the part.

    I sorta figured there wasn't going to be an easy solution to the problem, but that it was worth it to ask.
    Maybe ill just make it a project and make my own counter from scratch so I can determine everything

    Thanks for your help guys!