A CO2 Traffic Light On An SAO

November 6, 2024 by 12 Comments

[David Bryant] clearly has an awareness of the impact of an excess concentration of CO2 in the local environment and has designed an SAO board to add a CO2 traffic light indicator to one of the spare slots on the official Hackaday Supercon 2024 badge.

The part used is the Sensirion SCD40 ‘true’ CO2 sensor, sitting atop an Adafruit rider board. [David] got a leg up on development by creating a simple SAO breakout board, which could have either the male and female connectors fitted, as required. Next, he successfully guessed that the badge would be based around the RP2040 running MicroPython and hooked up an Adafruit Feather RP2040 board to get started on some software to drive the thing. This made hooking up to the official badge an easy job. Since the SAO has only two GPIOs, [David] needed to decode these to drive the three LEDs. There are a few ways to avoid this, but he wanted to relive his earlier EE college years and do it the direct way using a pair of 74HC00 quad NAND gate chips.

We’ve seen a few CO2 monitors over the years. This sleek little unit is based around the Seeeduino XIAO module and uses an LED ring as an indicator. Proper CO2 monitors can be a little pricey, and there are fakes out there. Finally, CO2 is not the only household pollutant; check out this project.

Tiny LoRa GPS Node Relies On ESP32

October 17, 2024 by 10 Comments

Sometimes you need to create a satellite navigation tracking device that communicates via a low-power mesh network. [Powerfeatherdev] was in just that situation, and they whipped up a particularly compact solution to do the job.

As you might have guessed based on the name of its creator, this build is based around the ESP32-S3 PowerFeather board. The PowerFeather has the benefit of robust power management features, which makes it perfect for a power-sipping project that’s intended to run for a long time. It can even run on solar power and manage battery levels if so desired. The GPS and LoRa gear is all mounted on a secondary “wing” PCB that slots directly on to the PowerFeather like a Arduino shield or Raspberry Pi HAT. The whole assembly is barely larger than a AA battery.

It’s basically a super-small GPS tracker that transmits over LoRa, while being optimized for maximum run time on limited power from a small lithium-ion cell. If you’re needing to do some long-duration, low-power tracking task for a project, this might be right up your alley.

LoRa is a useful technology for radio communications, as we’ve been saying for some time. Meanwhile, if you’ve got your own nifty radio comms build, or anything in that general milleu, don’t hesitate to drop us a line!

Witch’s Staff Build Is A Rad Glowing Costume Prop

October 2, 2024 by 9 Comments

Let’s say you’re going to a music festival. You could just take water, sunscreen, and a hat. Or, you could take a rad glowing witch’s staff to really draw some eyes and have some fun. [MZandtheRaspberryPi] recently undertook just such a build for a friend and we love how it turned out.

The concept was to build a staff or cane with a big glowing orb on top. The aim was to 3D print the top as a very thin part so that LEDs inside could glow through it. Eventually, after much trial and error, the right combination of design and printer settings made this idea work. A Pi Pico W was then employed as the brains of the operation, driving a number of through-hole Neopixel LEDs sourced from Adafruit.

Power was courtesy of a long cable running out of the cane and to a USB power bank in the wielder’s pocket. Eventually, it was revealed this wasn’t ideal for dancing with the staff. Thus, an upgrade came in the form of an Adafruit Feather microcontroller and a 2,000 mAh lithium-polymer battery tucked inside the orb. The Feather’s onboard hardware made managing the lithium cell a cinch, and there were no more long cables to worry about.

The result? A neat costume prop that looks fantastic. A bit of 3D printing and basic electronics is all you need these days to build fun glowing projects, and we always love to see them. Halloween is right around the corner — if you’re building something awesome for your costume, don’t hesitate to let us know!

Static Electricity And The Machines That Make It

September 30, 2024 by 20 Comments

Static electricity often just seems like an everyday annoyance when a wool sweater crackles as you pull it off, or when a doorknob delivers an unexpected zap. Regardless, the phenomenon is much more fascinating and complex than these simple examples suggest. In fact, static electricity is direct observable evidence of the actions of subatomic particles and the charges they carry.

While zaps from a fuzzy carpet or playground slide are funny, humanity has learned how to harness this naturally occurring force in far more deliberate and intriguing ways. In this article, we’ll dive into some of the most iconic machines that generate static electricity and explore how they work.

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A client uses an Augmented Alternative Communication board that speaks.

Tactile Communication Board Speaks The Truth

September 5, 2024 by 17 Comments

Sometimes, simple things can make a world of difference. Take for example a non-verbal person who can’t necessarily control a touch screen in order to tell someone else what they need or want or think.

The switches of the AAC board, plus the smaller version. This is where Augmentative and Alternative Communication (AAC) devices come in. Recently tasked with building such a device, [Thornhill!] came up with a great design that houses 160 different phrases in a fairly small package and runs on CircuitPython.

Basically, the client presses the appropriate snap-dome button button and the corresponding phrase is spoken through the speaker. The 10×16 grid of buttons is covered with a membrane that both feels nice and gives a bit of protection from spills.

The buttons can achieve high actuation forces and have a crisp tactile response, which means they’re probably gonna go a long way to keep the user from getting frustrated.

This handy AAC board is built on the Adafruit RP2040 Prop-Maker Feather and two keypad matrices. If this weren’t useful enough as it is, [Thornhill!] also built an even smaller version with 16 buttons for the client to wear around their neck.

Did you know? AAC boards aren’t just for humans.

A render of a BiC Cristal ballpoint pen showing the innards.

This Is How A Pen Changed The World

April 29, 2024 by 80 Comments

Look around you. Chances are, there’s a BiC Cristal ballpoint pen among your odds and ends. Since 1950, it has far outsold the Rubik’s Cube and even the iPhone, and yet, it’s one of the most unsung and overlooked pieces of technology ever invented. And weirdly, it hasn’t had the honor of trademark erosion like Xerox or Kleenex. When you ‘flick a Bic’, you’re using a lighter.

It’s probably hard to imagine writing with a feather and a bottle of ink, but that’s what writing was limited to for hundreds of years. When fountain pens first came along, they were revolutionary, albeit expensive and leaky. In 1900, the world literacy rate stood around 20%, and exorbitantly-priced, unreliable utensils weren’t helping.

Close-up, cutaway render of a leaking ballpoint pen. In 1888, American inventor John Loud created the first ballpoint pen. It worked well on leather and wood and the like, but absolutely shredded paper, making it almost useless.

One problem was that while the ball worked better than a nib, it had to be an absolutely perfect fit, or ink would either get stuck or leak out everywhere. Then along came László Bíró, who turned instead to the ink to solve the problems of the ballpoint.

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Space Mirrors: Dreams Of Turning The Night Into Day Around The Clock

April 3, 2024 by 28 Comments

Recently, a company by former SpaceX employee Ben Nowack – called Reflect Orbital – announced that it is now ready to put gigantic mirrors in space to reflect sunshine at ground-based solar farms. This is an idea that’s been around for a hundred years already, both for purposes of defeating the night through reflecting sunshine onto the surface, as well as to reject the same sunshine and reduce the surface temperature. The central question here is perhaps what the effect would be of adding or subtracting (or both) of solar irradiation on such a large scale as suggested?

We know the effect of light pollution from e.g. cities and street lighting already, which suggests that light pollution is a strongly negative factor for the survival of many species. Meanwhile a reduction in sunshine is already a part of the seasons of Autumn and Winter. Undeniable is that the Sun’s rays are essential to life on Earth, while the day-night cycle (as well as the seasons) created by the Earth’s rotation form an integral part of everything from sleep- and hibernation cycles, to the reproduction of countless species of plants, insects, mammals and everyone’s favorite feathered theropods.

With these effects and the gigantic financial investments required in mind, is there any point to space-based mirrors?

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