I'm looking to build a small scoreboard/timer. See attached. Two-digit home and away scores, a four-digit timer display, four small LEDs that indicate what quarter of the game you're in. A rotary encoder which you turn to set the starting time, push it to start the timer, push again to pause. A reset button to start a new game (set both scores and the timer to zero, the period to 1). Master power switch to turn the whole thing on and off. Something that's not in this drawing, which would be nice is a buzzer for when time runs out. I'm pretty much a complete beginner with Arduino, but all the great tutorials and great community have given me a false sense of confidence.
I bought this for the timer display, which in retrospect is a little silly, because I also bought some max7219 chips to control the four score display digits (which are these), and I could control all my LEDs with just a couple of max7219 chips, rather than adding this other timer display that has its own controller and its own pins. Also, it wasn't until the large single-digit displays arrived that I realized the max7219 can only control common cathode displays, and these are anode. I'm starting to realize this is like trying to fix anything around the house: it's never just ONE trip to Home Depot.
So I have a couple of questions about this project:
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Should I ditch both these displays and buy new ones that are all common cathode and controlled by max7219 chips, or should I forge ahead, and is there a way to control multiple common anode LED displays that I don't know about (I've done some searching...)?
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I count like 5 inputs, and depending on how I control the displays, maybe like 7 outputs, for a total of 12 pins. Seems like I should be able to squeeze this all onto my Arduino Uno, but am I wrong?
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And on a related note, I've never programmed anything this complex before; there will need to be various states, like are we at the start of a game, so you can set the timer, or are we in between periods, or is the timer paused, so you can't? Is it the end of the game, so pushing the timer start/stop shouldn't do anything... My sense is that this level of branching logic is something that Arduino is capable of, but I remember a while back reading something about the difference between Raspberry Pi and Arduino, and it made it sound like there's a point in the complexity of a given project at which the relatively simple, looping structure of Arduino can't really perform.
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I don't have a good handle on how to calculate how much power I need; could someone give me a hint on this? I know that most of what I've got is pretty low-power, so I should be okay with just 5v from the Uno, but these are large-ish displays I've chosen for the four score digits... If I swapped these digits out for common cathode, as related to the earlier question, I was thinking of getting some that are even a little bigger, like 1.5".
Thanks in advance for any help!
- P
