Number display LED matrix (MyFirstProject)

Projects General Guidance
1

hello,
(i previs this post with saying i am new to arduino.) I am an IT professional with mild programming experience.

this started with me trying to repair a scoreboard at a local inline hockey rink. The old scoreboard had 120V circuits with incandescent lightbulbs and hasn't worked in years. Called the manufacturer and no parts to fix. The idea is to upgrade the scoreboard to LEDs and use an arduino board to control. The total scoreboard will have 2 digits for the home team, 2 digits for the Guest team, 4 digits for the time clock. i LED each for periods 1-3 with 1 LED for OT. with other potential functionality.

I am testing this using tinkercad. It has the Adafruit_NeoPixel library.

All I want to do at this point is use the serialinput in tinkercad to send a number and have it display on the LEDs. I'm sure once I figure this out I'll have more questions but I'm trying to start small.

I've attached a picture of what this looks like in tinkercad
digital pin for LEDs is pin 6.

I want to start with learning how to display a 2 digit number in an LED matrix.

Any help or advice will be greatly appreciated.

i know this is very incomplete, but here's what i have so far, but this is mostly borrowed code. I'm not sure where to go from here with regard to the serialinput and getting it to display on the LED matrix:

#include <Adafruit_NeoPixel.h>

#define PIN 6
#define NUMPIXELS 56

const int characterOffset = 28; //character offset for next digit

int charLayout[10][27] = {
{1,1,1,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,0,0,1,1,1,1,1}, //0
{0,0,0,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1}, //1
{1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1}, //2
{1,1,1,1,1,0,0,0,0,0,0,1,1,1,1,1,0,0,0,1,1,0,0,0,1,1,1,1}, //3
{1,0,0,1,1,0,0,1,1,0,0,1,1,1,1,1,0,0,0,1,1,0,0,0,0,0,0,1}, //4
{1,1,1,1,0,0,0,1,1,0,0,0,1,1,1,1,0,0,0,1,1,0,0,0,1,1,1,1}, //5
{1,1,1,1,0,0,0,1,1,0,0,0,1,1,1,1,1,0,0,1,1,0,0,1,1,1,1,1}, //6
{1,1,1,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1}, //7
{1,1,1,1,1,0,0,1,1,0,0,1,1,1,1,1,1,0,0,1,1,0,0,1,1,1,1,1}, //8
{1,1,1,1,1,0,0,1,1,0,0,1,1,1,1,1,0,0,0,1,1,0,0,0,0,0,0,1}, //9

} ;

void setup() {
Serial.begin(9600); // initialize serial communication
pixels.begin(); // This initializes the NeoPixel library.
pinMode(6, OUTPUT);

}

void loop() {

}

void setNumber(int side, int displayNum) {
int sideOffset = sidecharacterOffset2;
int ones = (displayNum%10);
int tens = ((displayNum/10)%10);
for(int k=0;k<15;k++){
toggleLocation(side, k+sideOffset, charLayout[tens][k]);
toggleLocation(side, k+characterOffset+sideOffset, charLayout[ones][k]);
}

pixels.show();
}

Tickercad 2dig.png
Tickercad 2dig.png828×379 178 KB

2

int charLayout[10][27] Why waste 540 precious bytes of RAM to store less than forty bytes of (fixed) information?

3

can you explain? or perhaps recommend a better way to do that?
thanks

4

27 ones or zeroes would fit neatly into one 32 bit integer variable (four bytes)
Leave them in RAM for now, and when you:be got confidence that you can handle flash memory (PROGMEM) leave them there.

5

I'm surprised the compiler isn't complaining, but you have your array defined as 27 integers per number, but you are using 28.
As was mentioned, a 4x7 led matrix can be represented by 4 bytes of memory, which can be quite important depending on which arduino you are using. The UNO/nano/etc that are based on an atmega324 only have 2048 bytes of ram, your array uses over 1/4 of that. With a single color LED matrix it is not unusual to represent each LED with a single bit, giving you 8 per byte, and greatly reducing the memory requirements. The program gets a bit more complex, but the benefits usually far outweigh the costs of a bit of additional complexity.

How bright does the display need to be? The neopixels are very bright in a dark room, but may not be bright enough for your scoreboard. Are you ever going to want to change the color of the LEDs? If not, might be better to use a regular single-color LED, which are available in high-brightness versions.

6

Single-colour score boards can be made with large common-anode 7-segments displays and a member of the TPIC shift register family.
See this page.
Example code on the same page.
Leo..