digitalWrite() not working with 7 segment display

Other Hardware General Electronics
1

Hello people! I want to make an animation with a 7 segment display.
I've a problem when I want to turn on a display, digitalWrite() method doesn't work.
Here's my circuit design:

Circuito Arduino - diplay 7 segmentos
Circuito Arduino - diplay 7 segmentos882×348 58.7 KB

And here's my code:

// variables
byte pins[] = { 1, 2, 3, 4, 5, 6, 7 };

const byte Segments[] =
{
  0b11000000, // 0
  0b11001111, // 1
  0b10100100, // 2
  0b10000110, // 3
  0b10001011, // 4
  0b10010010, // 5
  0b10010000, // 6
  0b11000111, // 7
  0b10000000, // 8
  0b10000011, // 9
};

void setup()
{
  for(int i = 0; i < sizeof(pins); i++)
  	pinMode(pins[i], OUTPUT);
}

void loop()
{
  for(int i = 0; i < sizeof(Segments); i++)
  	SetDisplay(Segments[i]); 
}

void SetDisplay(byte shownNumber){
  byte segments = Segments[shownNumber];
  for (int i = 0; i < sizeof(segments); i++){
  	digitalWrite(pins[i], segments & (0x40 >> i));
  }
}
2

Is the display a common anode display?

Is that writing a LOW to the segments that you want lit?
A Serial print there might shed some light (:slight_smile: pun intended).
You will need a Serial.begin(baud) in setup to use the serial port.

Don't use pin 1 for a segment. It is the serial TX pin.

3

Real, or simulated hardware?

4

I forget that we have to ask that, nowadays.

5

Isn't the size always going to be 1 byte?

6

Hi,

byte pins[] = { 1, 2, 3, 4, 5, 6, 7 };

And your picture show you are using pin 1 of the UNO, this is the Tx pin of the UNO that is used with pin 0 to program your code.
I would suggest you use these pins and reconfigure your circuit.

byte pins[] = { 2, 3, 4, 5, 6, 7, 8 };

Tom... :smiley: :+1: :coffee: :australia:

7

Simulated

8

Yes, it is a common anode display.
Then, I want to write a HIGH statement.
Lastly, I'll change pin 1 for another.
Thanks @groundFungus !

9

You got the wrong size:

sizeof() returns strictly the compile-time size in bytes of a variable or type.

BTW thanks for posting code and circuit up-front, makes this an easy solution (I hope)!

10

Thank you Tom!

11

Ba ba bing.

12

If it is a common anode display, you must write a LOW to light a segment.

13

`sizeof (segments)' is 1 so this only goes through one of the seven bits. Try:

void SetDisplay(byte shownNumber){
  byte segments = Segments[shownNumber];
  for (int i = 0; i < 7; i++){
  	digitalWrite(pins[i], segments & (0x40 >> i));
  }
}
14

Have you READ posts #5, #9, #13... ?

15

There is no delay anywhere, it is going to look like all segments are on but dimmed when you get it working

16

I didn't know that

17

You're right. Thanks for your code, I copied it for another post. I didn't know some binary operators, interesting.

18

Yes, you're right. The size is always going to be 1.

19

I've just add it and it works better.

20

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