Instructables
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
  *breadboard
  *wire

 
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Step 1: 7-Segment displaying with potentiometer

Picture of 7-Segment displaying with potentiometer
Unbenannt2.jpg
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

Picture of 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...

DONT FORGET THE RESISTORS

Step 3: 2 digit 7 led segment

Picture of 2 digit 7 led segment
and this is the 2 digit COUNTER
dsmmoore9 months ago
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?
Naterenfo1 year ago
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?
mertaxoy (author)  Naterenfo1 year ago
hi Naterenfo,
you need certainly the pull down resistors for 3,3V
Nifty!

What about a 2 digit potentiometer controlled version?
mertaxoy (author)  lemonhead_oo71 year ago
its possible :)
is that arduino avalaible in the market easily??
mertaxoy (author)  Daniyal Khan2 years ago
yes, is it !

http://www.ebay.com/itm/Arduino-UNO-2011-Version-ATMEGA328P-PU-AVR-MCU-Board-USB2-0-Cable-/180833433758?pt=LH_DefaultDomain_0&hash=item2a1a83389e
kyubok3 years ago
can u help me?,, how to program a 2 digit 7segment display, for count up and count down.... pls.. guide me...
mertaxoy (author)  kyubok3 years ago
so İ have added the 3th step for you pleas take a look at it ;)
feel free to ask me anything..
mailman00013 years ago
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)?
mertaxoy (author)  mailman00013 years ago
i think i forgot the pull up resistors from buttons to ground... (1kOHM)...
mailman00013 years ago
And I'm using the Arduino Uno by the way! This shouldn't make a difference,should it ?
mertaxoy (author)  mailman00013 years ago
no, it shouldn't...
mailman00013 years ago
what kind of 7 segment do you used for this project?
mertaxoy (author)  mailman00013 years ago
common cathode - http://www.conrad.at/ce/de/product/160172/7-SEGMENTANZEIGE-14-MM-A/SHOP_AREA_17651&promotionareaSearchDetail=005