A CO2 Traffic Light On An SAO

[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.

Interfacing Old Burglar Alarm Sensors Into HomeAssistant

The annoying thing about commercial smart home gear is its lack of interoperability. HomeAssistant is very flexible though, and it’s easy to use all kinds of gear—even stuff you bodge together yourself. [Jeff Sandberg] demonstrates that ably with his project to use ancient 1990s burglar alarm sensors in his modern smarthome setup.

The sensors in question are from an old GM Interlogix security system. The sensors themselves sit on doors or windows. They use magnets and a reed switch to sense if the door or window is opened. If so, they send out a radio message saying as much. All [Jeff] had to do was catch those messages and translate them for HomeAssistant.

To listen in on the sensors, [Jeff] employed a Nooelec NESDR—a software defined radio that could pick up the 319.5 MHz signals. The NESDR runs a tool called RTL_433, which can decode the sensor signals, and spit out MQTT messages to interface with HomeAssistant.

Much of the hard work was done already for [Jeff]—he just had to lace together the components. This is just a testament to the hard work by people in the HomeAssistant and SDR communities for figuring all this out and putting the tools online.

We’ve seen some neat HomeAssistant builds before, like this neat home control terminal. If you’re cooking up your own smarthome hacks, don’t hesitate to let us know!

DIY 3D Hand Controller Using A Webcam And Scripting

Are you ready to elevate your interactive possibilities without breaking the bank? If so, explore [Caio Bassetti]’s tutorial on creating a full 3D hand controller using only a webcam, MediaPipe Hands, and Three.js. This hack lets you transform a 2D screen into a fully interactive 3D scene—all with your hand movements. If you’re passionate about low-cost, accessible tech, try this yourself – not much else is needed but a webcam and a browser!

The magic of the project lies in using MediaPipe Hands to track key points on your hand, such as the middle finger and wrist, to calculate depth and positioning. Using clever Three.js tricks, the elements can be controlled on a 3D axis. This setup creates a responsive virtual controller, interpreting hand gestures for intuitive movement in the 3D space. The hack also implements a closed-fist gesture to grab and drag objects and detects collisions to add interactivity. It’s a simple, practical build and it performs reliably in most browsers.

For more on this innovation or other exciting DIY hand-tracking projects, browse our archive on gesture control projects, or check out the full article on Codrops. With tools such as MediaPipe and Three.js, turning ideas into reality gets more accessible than ever.

Phoniebox: A Family-Friendly Simple Music Box

Ever hear of the Phoniebox project? If not – tune in, that’s a hacker’s project your entire family will appreciate. Phoniebox is a software suite and tutorial for building a jukebox controlled through RFID cards, and it can play audio from a wide variety of sources – music and playlists stored locally, online streams like internet radio stations, Spotify, podcasts of your choice, and so on. It’s super easy to build – get a Raspberry Pi board, connect an NFC reader to it, wire up a pair of speakers, and you’re set. You can assemble a PhonieBox together with your kids over the weekend – and many do.

Want some inspiration, or looking to see what makes Phoniebox so popular? Visit the Phoniebox gallery – it’s endearing to see just how many different versions have been built over the six years of project’s existence. Everyone’s Phoniebox build is different in its own special way – you bring the hardware, Phoniebox brings well-tested software and heaps of inspiration.

You already have a case to house a  Phoniebox setup – if you think you don’t, check the gallery, you’ll find that you do. Experiencing a problem? There’s a wealth of troubleshooting advice and tutorials, and a helpful community. Phoniebox is a mature project and its scale is genuinely impressive – build one for your living room, or your hacker’s lair, or your hackerspace. RFID-controlled jukeboxes are a mainstay on Hackaday, so it’s cool to see a project that gives you all the tools to build one.

Dog Poop Drone Cleans Up The Yard So You Don’t Have To

Sometimes you instantly know who’s behind a project from the subject matter alone. So when we saw this “aerial dog poop removal system” show up in the tips line, we knew it had to be the work of [Caleb Olson].

If you’re unfamiliar with [Caleb]’s oeuvre, let us refresh your memory. [Caleb] has been on a bit of a dog poop journey, starting with a machine-learning system that analyzed security camera footage to detect when the adorable [Twinkie] dropped a deuce in the yard. Not content with just knowing when a poop event has occurred, he automated the task of locating the packages with a poop-pointing robot laser. Removal of the poop remained a manual task, one which [Caleb] was keen to outsource, hence the current work.

The video below, from a lightning talk at a conference, is pretty much all we have to go on, and the quality is a bit potato-esque. And while [Caleb]’s PoopCopter is clearly still a prototype, it’s easy to get the gist. Combining data from the previous poop-adjacent efforts, [Caleb] has built a quadcopter that can (or will, someday) be guided to the approximate location of the offending package, home in on it using a downward-looking camera, and autonomously whisk it away.

The retrieval mechanism is the high point for us; rather than a complicated, servo-laden “sky scoop” or something similar, the drone has a bell-shaped container on its belly with a series of geared leaves on the open end. The leaves are open when the drone descends onto the payload, and then close as the drone does a quick rotation around the yaw axis. And, as [Caleb] gleefully notes, the leaves can also open in midair with a high-torque yaw move in the opposite direction; the potential for neighborly hijinx is staggering.

All jokes and puns aside, this looks fantastic, and we can’t wait for more information and a better video. And lest you think [Caleb] only works on “Number Two” problems, never fear — he’s also put considerable work into automating his offspring and taking the awkwardness out of social interactions.

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Inkycal Makes Short Work Of E-Paper Dashboards

The e-paper “dashboard” is something we’ve seen plenty of times here at Hackaday. Use it to show your daily schedule, the news, weather, maybe the latest posts from your favorite hardware hacking website. Any information source that doesn’t need to be updated more than every hour or so is a perfect candidate. All you’ve got to do is write the necessary code to pull  down said data and turn it into a visually attractive display.

Well, that last part isn’t always so easy. There are plenty of folks who have no problem cobbling together a Raspberry Pi and one of the commercially available e-paper modules, but writing the software to turn it into a useful information center is another story entirely. Luckily, Inkycal is here to help.

This open source project uses Python to pull information from a wide variety of sources and turns it into an e-paper friendly dashboard. It works with Waveshare displays ranging from 4.2 inches all the way up to the massive 12 inch tricolor panels. While it could theoretically be deployed on any operating system running a modern version of Python, it’s primarily developed to be run under Linux and on the Raspberry Pi. All of the versions of the Pi are supported, so no need to spring for the latest and greatest model. In fact, the notoriously pokey Raspberry Pi Zero is their recommended platform thanks to its low power consumption.

With Inkycal on the Pi — they even provide a pre-configured SD card image — and the e-paper display hooked up, all you need to do is pick which sources you want to use from the web-based configuration page. Look ma, no code!

Not feeling like putting the hardware together either? Well, we might wonder how you’ve found yourself on Hackaday if that’s the case. But if you really would rather buy then build, you can get a pre-built Inkcal display right now on Tindie.

Mobile Coffee Table Uses Legs To Get Around

For getting around on most surfaces, it’s hard to beat the utility of the wheel. Versatile, inexpensive, and able to be made from a wide array of materials has led to this being a cornerstone technology for the past ten thousand years or so. But with that much history it can seem a little bit played out. To change up the locomotion game, you might want to consider using robotic legs instead. That’s what [Giliam] designed into this mobile coffee table which uses custom linkages to move its legs and get itself from place to place around the living room.

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