4-Digit 7-Segment LED Display + Arduino





Introduction: 4-Digit 7-Segment LED Display + Arduino

About: I love electronics, computers, and everything DIY!

I recently got a 4-Digit 7-Segment LED Display from Sparkfun, and couldn't wait to use it. Here, I will show you how to wire it, and some sample programs to use with it!

Step 1: Display Info

This is the way the display works. It's multiplexed, so you select the digit by setting its pin (we'll get into pins later) HIGH, and you select the segment by setting its pin LOW. You display multiple digits at once by rapidly cycling through them.
The Pins (digits are numbered from the left):
Digit 1: 1
Digit 2: 2
Digit 3: 6
Digit 4: 8
Segment A: 14
Segment B: 16
Segment C: 13
Segment D: 3
Segment E: 5
Segment F: 11
Segment G: 15
Decimal Point: 7

Step 2: Wiring the Display and Button

Now, to wiring! To make it easier for you, I am going to put the Arduino pin number first, then the display's pin number.
9--1 (resistor)
10--2 (resistor)
11--6 (resistor)
12--8 (resistor)

If this is too confusing, say so in the comments, and I'll rewrite it.
Connect the button to Arduino pin 13 and 5V.
I used 1K resistors, but you could get away with less.

Step 3: Programming

I'm pretty much just putting refrence links and files here.
Display Datasheet

Timer Program (I modeled my timer after this)

Attatched Files:

_4segTimer: Timer program

_4digitAni1: Animations

The programs still need some tweaking/additions, so I'll be updating them once in a while.

Update History:




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    66 Discussions

    hello again,still no success in getting the sketch to start counting.I am using a UNO v3 with a 5461A5 type readout.12 pin

    Im sure it must be something simple that is causing it to non start.

    Can you give me some idea's why I can't get the digits to start counting. I am sure i am working with the correct code, as the other code works well.but I cannot get this start counting.All my connections are correct.

    please help make an old happy !!.

    Please help

    There are only 12 pins on the display but your connecting pin 1 on the Ard to pin 14 on the display.... very confusing.

    2 replies

    some down in the comments:

    1--10 (a)
    2--7 (b)
    3--4 (c)
    4--2 (d)
    5--1 (e)
    6--11 (f)
    7--5 (g)
    8--3 (dot)
    9--12 (resistor) (d1)
    10--9 (resistor) (d2)
    11--8 (resistor) (d3)
    12--6 (resistor) (d4)

    10 and 11 reversed for me

    Tip: If you have 12-pin segment display your scheme will be like this:

    1--10 (a)
    2--7 (b)
    3--4 (c)
    4--2 (d)
    5--1 (e)
    6--11 (f)
    7--5 (g)
    8--3 (dot)
    9--12 (resistor) (d1)
    10--9 (resistor) (d2)
    11--8 (resistor) (d3)
    12--6 (resistor) (d4)

    1 reply

    i got it working, it is a 4 digit seven segment i got from an old DSTV Decorder, and controlling it over the serial monitor

    i has download it,but cant open in arduino IDE because that file is not pde

    Does the 4 digit file is the part one of the Segment?

    I dont get it how to wiring ?! Can anyone sent schematics or smth ? Thank You :)

    1 reply

    People should also be aware that there are differences when wiring CC (Common Cathode) and CA (Common Anode) 7-Segment displays, as well as addressing them with the code, or using shift registers / led drivers.

    To get the timer to work do I just copy and paste the file into the Arduino program?

    Could I possibly get a list of comments for what's happening in either the timer or animation program? I'm using a 4 digit display for a heart rate monitor and I want to know how I can display the BMP from my Arduino.

    It runs also with an ULN 2803 instad of the 4 transistors. where can i buy in europe the sma420564 ? I have only one in my arduino kit. mfg CK

    I am using an Arduino Mega 2560, and I am using analogWrite intead of digitalWrite because I don't have low value resistors at the moment :(

    1: the button doesn't work, maybe pin13 is cursed on my board + i like using the LED for error reporting. if you used other pins it won't work without a pull-down resistor, or reversing the code and using the internal pull-up. I suggest:

    in setup(). add: pinMode(xx, INPUT_PULLUP)

    in loop(). change: if (digitalRead(13) == HIGH) to: if (digitalRead(xx) == LOW)

    and the button connects between pin and ground. (xx any pin other than 13 ).

    2: the digits were reversed ie: it was counting from left to right. I suggest:

    int d1 = 9; int d2 = 10; int d3 = 11; int d4 = 12;

    instead of: int d4 = 9; int d3 = 10; int d2 = 11; int d1 = 12;

    3: Thank you for the instructable :)

    I smell spam, or you're just someone who doesn't understand the differences between my project and the one you linked.