HELP: RARE 9-Digit LED Display - Arduino Code and Wiring Needed

Hi, is there anybody here that has experience with 9-digit 7-segment LED displays driven by Arduino (Uno)? These are very rare types of displays…

Basically, I bought this one new on eBay, but there is no diagram or nothing that came with it.

There is a number on the side wall of the display, see photos.

Can you help me getting the inner LED connection scheme for this one, a wiring diagram to connect it to Arduino Uno, and some basic code to light the digits and the dots by Arduino?

I know multiplexing will be required…

ANY HELP APPRECIATED - I must do a project with this little guy lighting the numbers in time sequence from 0 to 128 (three times with three digits, independently) and also lighting the dots next to each third digit.

Any advice, link, part number sheet, or other insight greatly appreciated!

Go on. Use some imagination. 8 pins for 8 segments. 9 pins for digit common pins.

You just have identify whether it is common cathode or common anode.

There is plenty of code showing how to multiplex 4-digits or 8-digits. Just adapt for 9-digits.

Note that the Arduino can supply a modest current for the segments. You will need transistors or a driver chip for the 'commons'.


Get a multimeter and run in diode testing mode. Stick one probe on a pin, move the other one around the other pins. See what lights up. Repeat for all pins. This will tell you absolutely everything about the display. Which pins are anode/cathode which segment/digit they control.

As others stated, it will be really simple to use it.

Also, it's not rare in any way.

// Per.

it appears to be common cathode, some idea of the wiring may come from the six digit version in the second link


I know multiplexing will be required...

There's a whole forum section devoted to "LEDs and Multiplexing" so you may find some more tips there as well.