I am new in Arduino but I have experience in electronics.

I was wondering how can I make a countdown timer using a CD4510 and an Arduino UNO. I know you would suggest that I should connect my seven segment display on the IO pins but I can't do that because I will use multiple seven segment displays.

  • A display driver, like the MAX7219, can allow you to control up to eight 7-segment displays (or 64 individual LEDs) while only using two pins on the Uno. Jul 9, 2015 at 3:32
  • Thanks but I only have a limited amount of budget. Can you at least send me any link or tutorial that teaches how to use Arduino UNO and CD4510 counter? :) Jul 9, 2015 at 5:01
  • What do you mean by “countdown timer” ? Do you mean a circuit that waits for some interval to elapse? Why do you need any displays? (Ie just use an LED to signal when done waiting) Jul 9, 2015 at 5:12
  • I need to show the time left that is why I need displays :) Jul 9, 2015 at 5:46
  • What's a typical range you will count down? What frequency do counted events occur at? How many digits does the display need? Please edit question with answers to those items. You can drive (eg) four 7-segment displays by using four bits to turn on high-side power and seven bits to pull down low-side segments -- ie just need some resistors, some transistors, four displays, and Arduino -- no need for CD4510 if input frequency isn't too high. (I was assuming, due to your fixation on CD4510, that you have some external event to count; if just timing seconds, that's even simpler.) Jul 9, 2015 at 11:40

2 Answers 2


The CD4510 does not seem at all appropriate for this task. It is a counter chip that counts up or down. You can do that with the Arduino. The output (of the CD4510) would be in "binary" and not suitable for driving a 7-segment display.

You can get 8 digit 7-segment displays on eBay for around $2. Surely that fits within your budget?

  • Ok, but i'm not sure if my local electronic shop has it :)) also I will use CD4511 to decode the binary and display it, i will only use the microcontroller for UP/DOWN and for CLOCKINPUT :)) Jul 9, 2015 at 9:49
  • @MiguelLorenzo: Why do you keep wanting to use extra chips to do what the Arduino can do on its own, or vice versa? Jul 9, 2015 at 12:58
  • Because arduino uno has limited ports only and I would use multiple timers and multiple sensors for my device :)) Jul 10, 2015 at 10:59
  • In that case see Is there a way to have more than 14 Output pins on arduino?
    – Nick Gammon
    Jul 10, 2015 at 21:37

I can use CD4510 to make a countdown timer, I just need to connect CLOCK INPUT to the Digital IO pins located in the arduino microcontroller and use pulse with modulation (pwm) for the code

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