Large Digit Driver Hookup Guide

Contributors: Shawn Hymel
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Large numerical displays are a great addition to any project where you want to be able to see information at a distance. Scorekeepers and lap timers would be a great application for large 7-segment LED displays. The Really Big 7-Segment Display (6.5") fits that bill nicely. Driving several displays at the same time would be handy, which is where the Large Digit Driver board comes in.

7-Segment Display - 6.5" (Red)

7-Segment Display - 6.5" (Red)

SparkFun Large Digit Driver

SparkFun Large Digit Driver


HX711 Large Digit Driver board

The Large Digit Driver can be soldered directly to the bottom of the 7-Segment Display.

HX711 board attached to large 7 segment display

Several Large Digit Drivers can be chained together to create a display with multiple digits.

HX711 boards chained together

Covered in This Tutorial

In this tutorial, we will give you an overview of the Large Digit Driver and provide an example of hooking up the driver to an Arduino:

  • Board Overview -- To begin, we'll go over each of the pins on the breakout board and their function.
  • Hardware Hookup -- In this section, we'll show you how to hook the Large Digit Driver up to an Arduino.
  • Example: One Large Digit -- Here, we give an example of an Arduino sketch to control one of the large 7-segment displays through the Large Digit Driver.
  • Example: Two Large Digits -- We show how to daisy chain two large 7-segment displays together and control them with two Large Digit Drivers.
  • Resources and Going Further -- This section gives some additional resources for getting more out of the Large Digit Driver.

Materials Used

To follow along with this tutorial, you will need the following materials. You may not need everything though depending on what you have. Add it to your cart, read through the guide, and adjust the cart as necessary. You will need a few components and tools to follow along with this tutorial. Here is the minimum parts needed for one 7-segment display.

For each additional digit you want to add, you will need:

Recommended Reading

Before getting started with the Large Digit Driver, there are a few concepts that you should be familiar with. Consider reading some of these tutorials before continuing:

What is an Arduino?

What is this 'Arduino' thing anyway? This tutorials dives into what an Arduino is and along with Arduino projects and widgets.

Shift Registers

An introduction to shift registers and potential uses.

How to Solder: Castellated Mounting Holes

Tutorial showing how to solder castellated holes (or castellations). This might come in handy if you need to solder a module or PCB to another PCB. These castellations are becoming popular with integrated WiFi and Bluetooth modules.