Introduction: 7-Segment-Display

About: . if(!success) try again; .

I want to show you in this "Instructable" how to control 7-Segment-Display

What you need:
  *Arduino Duemilanove
  *a lot of 7-Segment-Display
  *a lot of push Button
  *a potentiometer
  *8 x 120 Ohm resistor
  *4 x 1k2 Ohm resistor
  *2 x 1k Ohm resistor
  *4 x BC547 Transistor
  *1 x 74HC595

Step 1: 7-Segment Displaying With Potentiometer

On this step i worked with a shiftregister (74HC595). I connected the pins of 7-Segment to the shiftregister(a-g -> Q0, Q6). And a potentiometer to displaying the characters. Down here you can see the schematic.

latchPin = 8;     // pin 12 on the 74hc595
clockPin = 12;  // pin 11 on the 74hc595
dataPin = 11;   // pin 14 on the 74hc595

And you can download the Programm Code

Step 2: Count Down and Up With 2 Buttons

This step is about controlling the display with 2 push buttons to count up and down. The schematic that you can see down here is very simple. I have connected the Segment Pins (A to G) in Arduino (Pin 2 to 8) and the reading buttons happens through Arduino Pin 13 (countup) and Pin 12 (countdown).
I used the debouncer library to read the switched button successfully...


Step 3: 2 Digit 7 Led Segment

and this is the 2 digit COUNTER



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    Can I get the circuit for 2 digit display??

    in step 2 program is not compiling its showing error like

    "sketch_mar24a.ino:1:22: fatal error: Debounce.h: No such file or directory

    compilation terminated."

    hi there :) i want to build your 2 buttons up/down counter but here is the deal that i dont know where i will put the resistors :( can you help me please ? :/

    thank you

    3 replies

    hi, try it without resistor, if you get problem, just try it like the attached picture..


    thank you for everything

    actually i have tried it today without resistor and nothing happened :/ what should i see when i connected it to the arduino and computer ? code works but no response from the breadboard :/

    I am looking to do a similar project but wish to use a 4 digit display and have each count up/down be by 0.1 therefore it could count like so 9.90, 10.00, 10.10, etc. How can I modify your code to do this?

    Hey there Mertaxoy,
    I am just getting started with Arduino programming, and I am copying your example as displayed here. Why do I get the feeling that if I press one of these buttons its going to short out? Am I missing something here? the way you have it wired on your Fritzing diagram appears that when the button is pushed, the 3.3v would go straight to ground...? are the ground wires supposed to go to the other side of the buttons, with pull down resistors?

    1 reply

    hi Naterenfo,
    you need certainly the pull down resistors for 3,3V

    its possible :)

    yes, is it !


    can u help me?,, how to program a 2 digit 7segment display, for count up and count down.... pls.. guide me...

    1 reply

    so İ have added the 3th step for you pleas take a look at it ;)
    feel free to ask me anything..

    How come it's not counting up or down? All of leds are off except the middle bar (g) and when I push ether one of the push buttons it cut off and back on once released. I even tried wiring a-g with 3V or 5V (high). Is there something else I maybe missing that's not in picture ( Count down and up with 2 push buttons)?

    1 reply

    i think i forgot the pull up resistors from buttons to ground... (1kOHM)...

    And I'm using the Arduino Uno by the way! This shouldn't make a difference,should it ?

    1 reply

    no, it shouldn't...

    what kind of 7 segment do you used for this project?