Solving the 8-Queens Puzzle with an Adafruit 8×8 Mini LED Matrix
Dennis wrote in to share a project that students at Storming Robots have been working on.
Received an Adafruit Mini 8×8 LED Matrix w/I2C Backpack today. After soldering and testing I wanted to try something else with it.
Some students here have been programming the classic 8-Queens puzzle where 8 queens must be placed on a chess board such that no two queens can take each other. I thought the 8×8 matrix would make a good ‘chessboard’. Each lit LED is a placement for a queen in a particular solution. I have it hooked up to a large “breadboard Arduino” that I like using for testing things out. Naturally this will work with an Uno/Mega just fine. For more info on the 8-Queens problem see the Wikipedia article.
Note: It runs through the 92 solutions pretty fast. I was hand holding the camera and didn’t want to make the video too long. I might post a video later with a longer delay between solutions.
What’s better than a single LED? Lots of LEDs! A fun way to make a small display is to use an 8×8 matrix or a 4-digit 7-segment display. Matrices like these are ‘multiplexed’ – so to control 64 LEDs you need 16 pins. That’s a lot of pins, and there are driver chips like the MAX7219 that can control a matrix for you but there’s a lot of wiring to set up and they take up a ton of space. Here at Adafruit we feel your pain! After all, wouldn’t it be awesome if you could control a matrix without tons of wiring? That’s where these adorable LED matrix backpacks come in. We have them in two flavors – a mini 8×8 and a 4-digit 0.56″ 7-segment. They work perfectly with the matrices we stock in the Adafruit shop and make adding a bright little display trivial.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.