Seven segments from
individual LEDs

Seven segment displays are and have been very common in electronics. Usually, the 'seven segments' are encapsulated into a single component, with a common anode or cathode and seven (sometimes eight for a dot) control lines.

With our 3X7 project you'll construct a three-digit seven-segment display from discrete components. There are three control lines, one for each digit, and the seven segments are multiplexed.

The LEDs themselves shine though a thin 1mm PCB.

The project includes the following components:


Assembly inforgraphic | PDF

This project is a challenge to construct. Take your time. Assembly instructions are provided in the infographic. Make sure to be grounded to avoid static damage with the FETs, and to test them before and after soldering them.


We're fortunate that LuckyResistor has written a driver for 3X7, which can be used with an Arduino Uno or ported to other devices. The code can also be extended to control more digits.

All-black front option

White blocks front option

White blocks front option

Further information

3X7 was Project #28 of the Boldport Club. If you'd like to purchase this art piece, become a member and add one to your order through the shop.

The PCBs were lovingly manufactured by Eurocircuits. Toby Electronics have provided us with great prices for the LEDs.

Community contributions for this project are on our community site.