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  • PicŪ Basic


  • Large LED Display

    I've been asked to make a 100mm segment large display for a customer. They wanted it sunlight visible and all it needed to do was to count up in seconds, minutes and hours.

    I played with it a bit to display all kinds of things, so here's a few pictures. If you make an alarm clock out of this, you don't need an audible device. The light alone will raise the dead, it's that bright.

    It seems if you click the pictures they are displayed in full view in a window.





    Head on looking at these extreme LED's (and these are not the worst of them) you can see it looks like they are on fire ! Very unpleasant to look at from up close.



    and here it is time counting...



    The circuit is very simple, it's using 4094's that drives an open collector FET to switch each of the LED segments. The data gets sent serially to the display, that is to the 4094's.

    I'm using an RTC that gets cleared when a button is pressed and the time displayed is updated from there. I've also decided to make the PCB a bit more versatile, so instead of just seven segments it can display a dot, and if it's populated like in the picture a double dot. The dot's can be omitted and alternatively an arrow can be populated instead so it can be used as a service display as well.

    To have the arrow point to left instead of to the right, the board has to be mounted upside down. It's not a problem, you just have to change the code for that segment to have it dispay the right way up.



    This is the variations, left segment is upside down with an arrow to the left, a seven segment with a double dot, a segment with a single dot and a segment with a right arrow.



    The connections as you can see is fairly simple, a ribbon cable connects the low voltage signals and the wires is pos and neg (12V in this case) to the LED's. There are 4 LED's in series and 2 sets of these makes up each segment.

    I actually found some old displays I made about two hundred and fifty years ago, they were semi mechanical , defenately conventional and in those days seven segments were square, not the sleek slanted ones you can make today.



    Well, pics evolved, displays evolved and with Proton it's so darn easy to make these things nowadays... We all know components off late are getting smaller and smaller, and as you can see, so does the display boards