Is it possible to power four one digit seven segment displays with 2x 74HC4067?

Other Hardware LEDs and Multiplexing
1

So I'm trying to make a day counter, but the specifics of that can follow later. What I'm struggling with right now is seven segment displays. I have four of them (common anode) and I've hooked them up to a couple of multiplexers but when trying to power a single segment, more than one is lighting up and I have no idea why.

This is the very basic code I've written to try and get something out of the setup. Am I understanding how to use these demultiplexers correctly?

//                            --2--          --10-
//                          1|     |3      9|     |11
//                           |--0--|        |--8--|
//                          4|     |6     12|     |14
//                            --5--  7       --13-   15

void setup() {
  // put your setup code here, to run once:
  pinMode(2, OUTPUT);
  pinMode(3, OUTPUT);
  pinMode(4, OUTPUT);
  pinMode(5, OUTPUT);
  pinMode(12, OUTPUT);

}

void loop() {
  // put your main code here, to run repeatedly:

//Segment0
digitalWrite(5, LOW);
digitalWrite(4, LOW);
digitalWrite(3, LOW);
digitalWrite(2, LOW);

digitalWrite(12, HIGH);

//Segment1
digitalWrite(5, LOW);
digitalWrite(4, LOW);
digitalWrite(3, LOW);
digitalWrite(2, HIGH);

digitalWrite(12, HIGH);

//Segment2
digitalWrite(5, LOW);
digitalWrite(4, LOW);
digitalWrite(3, HIGH);
digitalWrite(2, LOW);

digitalWrite(12, HIGH);

//Segment3
digitalWrite(5, LOW);
digitalWrite(4, LOW);
digitalWrite(3, HIGH);
digitalWrite(2, HIGH);

digitalWrite(12, LOW);

//Segment4
digitalWrite(5, LOW);
digitalWrite(4, HIGH);
digitalWrite(3, LOW);
digitalWrite(2, LOW);

digitalWrite(12, HIGH);

//Segment5
digitalWrite(5, LOW);
digitalWrite(4, HIGH);
digitalWrite(3, LOW);
digitalWrite(2, HIGH);

digitalWrite(12, HIGH);
//Segment6
digitalWrite(5, LOW);
digitalWrite(4, HIGH);
digitalWrite(3, HIGH);
digitalWrite(2, LOW);

digitalWrite(13, HIGH);

//Segment7
digitalWrite(5, LOW);
digitalWrite(4, HIGH);
digitalWrite(3, HIGH);
digitalWrite(2, HIGH);

digitalWrite(13, HIGH);

//Segment8
digitalWrite(5, HIGH);
digitalWrite(4, LOW);
digitalWrite(3, LOW);
digitalWrite(2, LOW);

digitalWrite(13, HIGH);

//Segment9
digitalWrite(5, HIGH);
digitalWrite(4, LOW);
digitalWrite(3, LOW);
digitalWrite(2, HIGH);

digitalWrite(13, HIGH);

//Segment10
digitalWrite(5, HIGH);
digitalWrite(4, LOW);
digitalWrite(3, HIGH);
digitalWrite(2, LOW);

digitalWrite(13, HIGH);

//Segment11
digitalWrite(5, HIGH);
digitalWrite(4, LOW);
digitalWrite(3, HIGH);
digitalWrite(2, HIGH);

digitalWrite(13, HIGH);

//Segment12
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);
digitalWrite(3, LOW);
digitalWrite(2, LOW);

digitalWrite(13, HIGH);

//Segment13
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);
digitalWrite(3, LOW);
digitalWrite(2, HIGH);

digitalWrite(13, HIGH);

//Segment14
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);
digitalWrite(3, HIGH);
digitalWrite(2, LOW);

digitalWrite(13, HIGH);

//Segment15
digitalWrite(5, HIGH);
digitalWrite(4, HIGH);
digitalWrite(3, HIGH);
digitalWrite(2, HIGH);

digitalWrite(13, HIGH);

}

More details here

IMG_20200627_222512.jpg
IMG_20200627_222512.jpg1255×941 211 KB

2

IMG_20200627_222512.jpg
Unfortunately that image gives us no idea at all how you are connecting this.

In any case, for a number of reasons, 74HC4067 multiplexers are utterly unsuitable for this purpose. :astonished:

You need a MAX7219. Just buy two or three of these kits:

Or these ones

which used to be more expensive but are now actually cheaper and more useful if you wish to stack matrix arrays (or would be cheap except for the postage costs presently added during Covid-19 :cold_sweat: ).

The point is that you do not install the matrix arrays from the kits themselves - or their socket pins, but just solder to the positions on the PCB and you have a durable and reliable assembly to drive your own seven-segment displays.

Why did I say two or three? Well, you can fully assemble the first one as the matrix with which it comes and practice programming it. Then the second one for your current project and the third one - for the next! :grinning:

Considering the cost, it makes no sense to just buy one!

3

Paul__B:
Unfortunately that image gives us no idea at all how you are connecting this.

Yeah, my bad!

Paul__B:
In any case, for a number of reasons, 74HC4067 multiplexers are utterly unsuitable for this purpose. :astonished:

All right, I've ordered one of the things you suggested, thanks for the advice!