I have a 2 digit 7 segment display with 18 pins. How do i use it with arduino ?

Can anyone help me to use a 2 digit 7 segemnt display with an Arduino Micro ? I need a schematic. The model is ELD-511SURWA/S530-A3.

Just google "common-cathode seven segment LED Arduino", or look at the Playground.

none of the results show a 2 digit display with 18 pins

Go on. 7-seg + decimal point is 8 LEDs + one common. e.g 9 pins per digit.

You can identify each pin with a DMM. And determine whether it is common cathode or common anode.

Google for 7-seg. You will find a matching display. And matching driver code.

If you buy something cheap, you have to do your own homework.

If you want to have your hand held at every stage, buy Sparkfun or Adafruit who will give you guaranteed results.


With a 5V source and a 1K resistor, see if the pinout matches one of these.

But I don’t have a power supply and a 1k resistor. Can I use the 5v output of the Arduino ?

You can't use the 7-seg without resistors. So your first job is to get onto Ebay and buy some from a local seller.

You pay a little more for the resistors but they arrive in 1-2 days. It is worth buying an assortment.

Yes, you can use the 5V from your Uno. Any resistor from 220R to 4k7 should be good enough to test the LEDs.


Ok, but i have an Arduino Micro. Will it work ?

A Micro is just a regular Arduino like a Uno, but the processor is in a different package, so as long as you don't exceed 20mA per pin (in or out), and about 200mA for the whole package, you should be OK.