Adafruit Learning System Weekly Update: The 7-Segment Display

This week on the Adafruit Learning System, we published an update to the LED Backpacks guide, which includes directions on using one of my favorite Adafruit products, the 7-segment backpack. So today, let’s take a look at some of the many awesome guides that use the 7-segment display. But first, here is my favorite new guide this week!

Favorite New Guide

Plastic capsule containing electronics

Ladyada and Philip Burgess created a new guide to help you cheat your way to becoming a chess champion!

Social media is abuzz lately over the prospect of cheating in tournament strategy games. Is it happening? How is that possible with officials watching? Could there be a hidden receiver somewhere? What can be done to rectify this? These are probing questions!

We’ll get to the bottom of this by making a simple one-way hidden communicator using Adafruit parts and the Adafruit IO service. Not for actual cheating of course, that would be asinine…in brief, a stain on the sport…but to record for posterity whether this sort of backdoor intrusion is even plausible or just an internet myth.

The Timeless Awesomeness of the 7-Segment Display

If you are making a simple alarm clock or a time machine inside a DeLorean, then look no further than the simple 7-segment display. These projects will show you how.


DeLorean Time Circuit

Getting the big question right out of the way: no, we won’t be selling these. Legally, we can’t, for trademark reasons. But it’s generally okay for anyone to create replica props for their own personal use, so we hope this writeup will inspire some cool projects among our customers…

From the moment these LED displays made an appearance on our weekly Ask an Engineer show, comparisons were being made to the DeLorean time circuit from the Back to the Future films. It was a moral imperative then to make a demo! If you’re handy with Arduino and some shop tools, you should be able to pull off something similar (better, even), or adapt the ideas to other projects. This was quickly built in fun, so please don’t expect the same level of polish as a finished product tutorial.

Ninja Timer: Giant 7-Segment Display

Ever wanted to build an enormous timer using 7-segment displays? Here’s a way to do just that using NeoPixel strips for the segments and acrylic diffusers to blend the individual LEDs into seamless light sources.

This guide shows how to build 12″ tall digits, each made from a meter of NeoPixels cut into segments and then joined at angles. Each digit is controlled by a single Arduino data pin, so you can make and use as many digits as you like, dependant on power supply and available Arduino pins.

Plus, you’ll build rugged buttons for starting and stopping the timer, and control an ear-splitting car horn from your Arduino!


Garmin Lidar Lite Range Finder

LiDAR (an acronym for light detection and ranging) is a technology that measures the distance to a target by shining a pulsed laser light on it and analyzing the reflections.

The surface that you are bouncing the laser light off of will impact how good of a reading you get. Smooth, reflective surfaces will tend to bounce the light away from the sensor depending on the angle at which the light is hitting the surface. If the light is coming straight at the surface, it will reflect directly back and you will get a good reading. The further from straight-on you get, the poorer of a reading you will get, eventually you’ll get no reading at all. Glass, mirrors, and any highly polished surface will be have this way.


Trinket React Counter

Inspired by Facebook “Reactions”. You press the button, and the number count gets displayed on the LED screen.

Looks like a novelty product, but this can be used for all sorts of useful stuff like keeping track of attendees at an event, keep track of a score for a game or anything else that needs a tally counter.

ALS Deep Cut

With so many guides on the Adafruit Learning System, some amazing guides of years past get buried and lost. ALS Deep Cuts brings these guides back up to the surface. This week’s guide is from back in 2018.

Crickit Harmonic Drawing Machine

You can build a machine that draws wonderful geometric curve patterns using Crickit, Circuit Playground Express, TT motors, and LEGO. This type of harmonograph drives the pen armature from two motorized hubs running at different speeds, generating and mapping complex harmonic motion!

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