- Joined Apr 2, 2016
I'm a few months into teaching myself and my kids electronics with a breadboard, and I just designed my first circuit. It lights every LED on an 8x8 matrix in sequence, scanning top to bottom, left to right, and the speed is adjustable with a trim pot.
I know this would be easy with an Arduino or microcontroller, but I wanted to see if I could do it with a 555, two 4017s, and two 7406 hex inverters. I got it to work, and I imagine most here know the rush that comes from seeing your first personal project succeed.
However, since I just cobbled it together, I'd like to run it by a few of the old timers here to make sure I'm not putting undue stress on components, didn't forget anything, etc. When it's at full speed at 6V, the matrix looks completely lit up, but a dull pink. I ran it at 9V briefly, which looked great, but I'm not sure if I would be hurting the matrix that way.
As you've probably guessed, it uses one 4017 to source each row in sequence, and the other 4017 to sink a column through the 7406 inverters. When the first 4017 hits its 9th output, it sends a clock pulse to the second 4017 and resets itself. Attached are my (pseudo) circuit diagram and the spec sheet for the matrix. I know the diagram is a mess in the center, I colored the clock wires to make things a bit clearer.
Any feedback would be appreciated.
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