Air Quality Monitor Plays Game Of Life

October 3, 2025 by 8 Comments

The problem with air quality is that you can’t really tell how good or bad it is just by looking…unless it’s really bad, that is. It’s usually more helpful to have some kind of sensor that can tell you what the deal is. To that end, [Arnov Sharma] built a neat air quality monitor with a fun twist.

A Raspberry Pi Pico W acts as the heart of the build, armed with an SGP40 gas sensor. This sensor is intended for monitoring total volatile organic compounds in the air, which can be a useful measure of air quality in at least one dimension. It reports a simple air quality score from 0 to 500, based on a 1-1000 ppm ethanol equivalent reading. Based on the sensor’s output, the Pi Pico drives an LED matrix display — setting it green for good quality air, yellow for moderate, and red for poor air quality (i.e. high VOC content). The fun part is that rather than just show a simple color, the display plays Conway’s Game of Life to create an animated visual. We’d love it even more if poor air quality lead to the premature death of individual cells, making it even more interactive.

We’ve featured other air quality monitors before; often, it’s desirable to monitor CO2 levels to determine whether more ventilation is needed.

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2025 One Hertz Challenge: A Game Of Life

August 13, 2025 by 6 Comments

The 2025 One Hertz Challenge asks you to build a project that does something once every second. While that has inspired a lot of clock and timekeeping builds, we’re also seeing some that do entirely different things on a 1 Hz period. [junkdust] has entered the contest with a project that does something rather mathematical once every second.

[junkdust] wanted to get better acquainted with the venerable ATtiny85, so decided to implement Conway’s Game of Life on it. The microcontroller is hooked up to a 0.91″ OLED display with a resolution of 128 x 32 pixels, however, [junkdust] only elected to implement a 32 x 32 grid for the game itself, using the rest of the display area to report the vital statistics of the game. On power up, the grid is populated with a random population, and the game proceeds, updating once every second.

It’s a neat little desk toy, but more importantly than that, it served as a nicely complicated test project for [junkdust] to get familiar working inside the limitations of the ATtiny85. It may be a humble part, but it can do great things, as we’ve seen many times before!

2025 Hackaday One Hertz Challenge
An E-ink display showing Conway's Game of Life, with a solar cell beneath it

Solar Powered Game Of Life Follows The Sun’s Rhythm

July 28, 2023 by 6 Comments

Conway’s Game of Life is a beautiful example of how complex behavior can emerge from a few very simple rules. But while it uses biological terminology such as “cells”, “alive” and “generation”, the basic game is too simplistic to be a model for any real-world biological process. It’s easy to add features to make it a bit more life-like, however, as [David Hamp-Gonsalves] has done by giving the Conway’s creation something of a circadian rhythm.

The basic idea is that the speed at which [David]’s Game of Life evolves is governed by the amount of ambient light. The game runs off a solar cell that charges a battery, with the battery’s voltage determining how long it takes to advance the game by one generation. The system is therefore highly active in full sunlight, and grinds almost to a complete halt at night.

An ESP32 runs the simulation and outputs the result to a 400 x 300 pixel e-ink display. The display is extremely power-efficient by its very nature; the ESP’s main processor core, on the other hand, is deliberately placed into deep sleep mode most of the time to save as much power as possible. The Ultra Low Power (ULP) co-processor, meanwhile, keeps an eye on the lithium battery’s voltage as it’s slowly being charged by the solar cell. When the voltage reaches 3.3 V, the main CPU wakes up and computes the Game’s new state. In bright sunlight this happens every few seconds, while on an overcast day it could take minutes or even hours.

[David]’s interesting idea of changing Life‘s activity based on the amount of energy available turns the Game into something resembling a cold-blooded animal. We’ve seen a similar approach in a “solar creature” that runs a Life-life simulation on a seven-segment LCD. If it’s speed you care about however, you’re better off implementing Life in an FPGA.

This RISC-V CPU Games In Rust From Inside The Game

July 17, 2023 by 14 Comments

[Xander Naumenko] has created something truly impressive — a working RISC-V CPU completely contained in a Terraria world. And then for added fun, he wrote the game of pong, playable in real time, from within the game of Terraria. It’s all based on the in-game wiring system, combined with a bit of a hack that uses the faulty lamp mechanic to create a very odd AND gate. In Terraria, the existing logic gates have timing issues that make them a no-go for complicated projects like this one. The faulty lamp is intended to do randomized outputs, by stacking multiple inputs to get a weighted output when a clock signal is applied. The hack is to simply give this device a single input, turning it into a clocked IF gate. Two of them together in series makes a clocked AND gate, and two in parallel make a clocked OR gate.

Why would [Xander] embark on this legendary endeavor? Apparently after over eight thousand hours clocked in game, one gets a bored of killing slimes and building NPC houses. And playing with the game’s wiring system turned on a metaphorical lightbulb, that the system could be used to build interesting systems. A prototype CPU, with a completely custom instruction set came next, and was powerful enough to compute Fibonacci. But that obviously wasn’t enough. Come back after the break for the rest of the story and the impressive video demonstration.

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This Retro Game Console Puts Vacuum Fluorescent Display To Good Use

March 7, 2023 by 4 Comments

Small in size, low-resolution, blocky segments, and a limited color palette — all characteristics of the typical vacuum fluorescent display, any of which would seem to disqualify them as the display of choice for a lot of applications. But this is Hackaday, and we don’t really pay much attention to what we’re supposed to do, but rather to what’s fun and cool to do. So when we see something like a VFD game console, we just have to sit up and take notice.

In a lot of ways, the design of [Simon Boak]’s Arduino-based VFD console is driven by his choice of display. The Noritake Itron GU20X8-301 VFD is a “tricolor” display with eight rows of 20 rectangular pixels. Each pixel is composed of six short linear segments, with alternating red and blue colors. Turning on either set of segments yields one of the two base colors, while turning on both yields a sorta-kinda whitish color, if you squint a bit.

[Simon] chose a two-piece design for his console, with a separate controller and display. The controller holds the Arduino Nano and all the controls, plus a piezo buzzer for fun. The display case connects to the controller with a ribbon cable and holds the VFD power supply and driver. To celebrate the retro look of the VFD, both cases are decked out with woodgrain side panels. [Simon] chose appropriately blocky games for the console, like Snake, Conway’s Game of Life, and the venerable snow demo. We’d imagine Pong would be a good choice too, as well as perhaps Tetris if the display were flipped on its side.

We really like the look of this console, and we appreciate putting an otherwise obsolete display to use in a creative way. If you want to learn a little more about these displays, check out this love letter to the VFD.

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The Game Of Life Moves Pretty Fast, If You Don’t Use Stop Motion You Might Miss It

November 11, 2021 by 12 Comments

Munged Ferris Bueller quotes aside, Conway’s Game of Life is the classic cellular automata that we all reach for. The usual approach is to just iterate over every cell in the grid, computing the next state into a new grid buffer. [K155LA3] set out to turn that on its head by implementing Game Of Life in the hardware of an FPGA.

[K155LA3]’s version uses Chisel, a new HDL from the Berkley and RISCV communities. Under the hood, Chisel is Scala with some custom libraries that know how to map Scala concepts onto hardware. In broad strokes, Verilog and VHDL are focused on expressing hardware and then added abstraction on top of that over the year. Chisel and other newer HDL languages focus on expressing high-level general-purpose elements that get mapped onto hardware. FPGAs already map complex circuits and hardware onto LUTs and other slices, so what’s another layer of abstraction?

The FPGA chosen for this project is a Digilent Arty A7 with a VGA Pmod to turn the RGB444 into analog signals to actually display. What’s impressive about [K155LA3]’s implementation is just how fast it is. Even running at 60 frames per second it’s almost as fast as the monitor can handle. Of course, most computers lying around you could simulate a 60 x4 8 grid at 60 fps. Next, instead of connecting the grid logic to the 60 Hz VGA clock, he connects it to the 100 MHz board external oscillator. Now each pixel in each frame displayed contains over a million generations.

Unfortunately, even this small grid of 60×48 takes up 90% of the LUTs on the Artix-7. In the future, we’d love to see an even larger FPGA hardware implementation capable of handling grids that could hold whole computers in them. And naturally, this isn’t the first FPGA version of the Game Of Life here at Hackaday.

A Computer In The Game Of Life

November 21, 2020 by 22 Comments

We often hear the term “Turing-complete” without giving much thought as to what the implications might be. Technically Microsoft PowerPoint, Portal 2, and Magic: the Gathering all are Turing-complete, what of it? Yet, each time someone embarks on an incredible quest of perseverance and creates a computer in one of these mediums, we stand back in awe.

[Nicolas Loizeau] is one such individual who has created a computer in Conway’s Game of Life. Unlike electricity, the Game of Life uses gliders as signals. Because two orthogonal gliders can cancel each other out or form a glider eater if they intersect with a good phase shift, the basic logic gates can be formed from these interactions. This means the space between gates is crucial as signals need to be in phase alignment. The basic building blocks are a period-60 gun, a 90-degree glider reflector, a glider duplicator, and a glider eater.

All the Python code that generates these structures is on GitHub as the sheer size of the machine couldn’t possibly be placed by hand. The Python includes scripts to assemble the basic programs as a bank of selectable glider generators. It’s all based on Golly, which is an excellent program for simulating Conway’s Game of Life, among other things. While this isn’t the first computer in the Game of Life as [Paul Rendell] published a design in 2000 and [Adam Goucher] published a Spartan universal computer constructor in 2009, we think this is a particularly beautiful one.

The actual architecture has an 8-bit data bus, a 64-byte memory with two read ports, a ROM with 21 bits per line, and a one-hot encoded ALU supporting 8 different operations. Instructions have a 4-bit opcode which is decoding in a few different instructions. The clock is four loops, formed by the glider reflectors as the glider beams rotate. This gives the computer four stages: execution, writing, increment PC, and write PC to memory.

The Game of Life is an excellent example of Cellular Automaton (CA). There are several other types of CA’s and the history behind them is fascinating. We’ve covered this field before and delved into this beautiful fringe of computer science. Check out the video below to truly get a sense of the scale of the machine that [Nicolas] has devised.

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