LED Dot Matrix POV Font Generator

I have created a sweet little VBA program in Excel with a user interface that allows you to create patterns and fonts and format them in to hex strings ready for the C compiler of your choice. Check it out at Instructables. It was even Featured because people are really into flashy LED stuff. I used it to create a 5x8 font table for my future LED scrolling display. I also fed the font into my POV prototype. Check it out.


LED Scolling Dot Matrix Font & Graphics Generator 5x8 5x7 8x8 - More DIY How To Projects">

2 Digit 7 Segment Up/Down Counter

Using my limited background in electronics I have completed a fun little project. In my online research, there are quite a few forum posts and discussions about creating these type of simple counters. Ideally you could set all of this up using an AVR and save alot of real estate, but the IC's are cheap and there's no programming required. Here's what you need:

1 - 2 digit Common Cathode 7 segment display ( or 2 single digit CC displays)

1 - CD4093 - Quad 2-input NAND with Schmitt trigger inputs

2 - CD4029 - Binary/Decade Up Down Counter IC

2 - CD4511 - 7 segment display driver IC

2 - momentary switches normally open

1 - 2 position toggle switch

2 - 4 pole DIP switches (optional)

1 - 7805 voltage regulator

~10 - 10Kohm 1/4W resistors

2 - 100Kohm 1/4W resistors

14 - 330ohm 1/4W resistors

1- big breadboard

The DIP switches are optional. They are used to preset the digits you start at after a reset. The count increment is fixed as 1. I don't know how to change that. Anyway, you can check out my youtube video of the counter and the attached schematic to show you how it lays out.

The CD4093 basically acts as a switch debounce. Without it, the display just rapidly counts over and over.

The key to having this work is to trigger the "first" digit (i.e. the ones place) and connect the first CD4029 Carry Out pin to the Clock (trigger) pin of the "second" (i.e. the tens place) CD4029. It's not rocket science but you may find it useful.

All the parts cost me less than $3.00 and it was pretty fun

Post any comments or questions and I will try to help.

Here's a couple of useful links:

http://www.kpsec.freeuk.com/components/cmos.htm Full Data of 4000 Series CMOS chips

http://www.kpsec.freeuk.com/counting.htm Theory of counting circuits

http://www.avnet.com/ Cheap way to get the parts.