A doorblell made from a stepper motor and a hard drive

Minimalistic Doorbell Doesn’t Need An Internet Connection – Or Even A Power Supply

February 22, 2022 by Robin Kearey 57 Comments

Doorbells are among those everyday objects that started out simple but picked up an immense amount of complexity over the years. What began as a mechanism to bang two pieces of metal together evolved into all kinds of wired and wireless electric bells, finally culminating in today’s smart doorbells that beam a live video feed to their owners even if they’re half a world away.

But sometimes, less is more. [Low tech obsession] built a doorbell out of spare components that doesn’t require Internet connectivity or even a power supply. But it’s not a purely mechanical device either: the visitor turns a knob mounted on a stepper motor, generating pulses of alternating current. These pulses are then fed into the voice coil of an old hard drive, causing its arm to vibrate and strike a bell, mounted where the platters used to be.

Besides being a great piece of minimalistic design, the doorbell is also a neat demonstration of Faraday’s law of induction. The stepper motor is apparently robust enough to withstand vandalism, although we can imagine that the doorbell’s odd shape might confuse some well-meaning visitors too. If you’re into unusual doorbells, you might want to check out this one made from an old wall phone, as well as this electromechanical contraption.

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Making Something Gorgeous From Framing Lumber

February 6, 2022 by Matthew Carlson 17 Comments

Here at Hackaday, we typically cover things that blink, bleep, and occasionally they might even bloop. However, the name of the site is Hackaday. We’re about being clever, reusing things in new ways, and most importantly celebrating interesting projects. While not a traditional project that would grace the front page, we would argue that this nightstand made from framing lumber clearly belongs.

Framing lumber is infamous for being squirrely, weird, and heavily knotted. Most serious furniture makers avoid using the cheap stuff and opt for more expensive harder woods. Here in the US, the big box hardware stores carry cheap fast-grown soft pine that has significant amounts of warp and twist inherent in the wood. The process of getting it straight with right-angle corners is involved and even once it has been cut, the internal stresses inside the wood are released, rendering the board twisted and warped again over time. The timelapse process of planing, jointing, and cutting in the video has an almost therapeutic aspect to it. The results are two wonderful pieces of useful furniture that would look at home in most rooms.

The craftsmanship evident in the build is noteworthy but more impressive is the process of taking cheap and unfit materials and making something beautiful out of them. Perhaps if you’re inspired and decide to make your own nightstand this weekend, you can add some touch-sensitive electronics to it. Video after the break.

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Keep Track Of Toilet Paper Usage With This IoT Roll Holder

February 3, 2022 by Dan Maloney 51 Comments

Remember the Great Toilet Paper Crisis of 2020? We sure do, and it looks like our old friend [Vije Miller] does as well, while seemingly harboring a somewhat morbid fascination about how much paper every bathroom visitor is consuming. And to that end, we present his IoT toilet sheet tracker.

His 3D printed roll holder has a Hall effect sensor that counts revolutions of the roll and sends it to a NodeMCU. The number of sheets per roll is entered when the roll is changed, so some simple math yields the number of sheets each yank consumes. Or at least a decent estimate — [Vije] admits that there’s some rounding necessary. The best part of the build is the connection to Thingspeak, where sheet usage is plotted and displayed. Go ahead and check it out if you dare; at the time of writing, there was an alarming spike in sheet usage — a sudden need for 68 sheets where the baseline usage is in single digits. We shudder to think what might have precipitated that. The video below is — well, let’s just say there’s a video.

This isn’t the first time we’ve seen bathroom-based projects from [Vije Miller]. A few years back there was an attempt to freshen the air with plasma, and his IoT shower valve controller probably never scalded anyone accidentally.

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Remote control PCB next to its shell, with a breadboarded analog switch connected to the remote's onboard microcontroller, soldered to the pins responsible for button reading

Reusing Proprietary Wireless Sockets Without Wireless Hacking

January 31, 2022 by Arya Voronova 9 Comments

Bending various proprietary devices to our will is a hacker’s rite of passage. When it comes to proprietary wall sockets, we’d often reverse-engineer and emulate their protocol – but you can absolutely take a shortcut and, like [oaox], spoof the button presses on the original remote! Buttons on such remotes tend to be multiplexed and read as a key matrix (provided there’s more than four of them), so you can’t just pull one of the pads to ground and expect to not confuse the microcontroller inside the remote. While reading a key matrix, the controller will typically drive rows one-by-one and read column states, and a row or column driven externally will result in the code perceiving an entire group of keys as “pressed” – however, a digitally-driven “switch” doesn’t have this issue!

One way to achieve this would be to use a transistor, but [oaox] played it safe and went for a 4066 analog multiplexer, which has a higher chance of working with any remote no matter the button configuration, for instance, even when the buttons are wired as part of a resistor network. As a bonus, the remote will still work, and you will still be able to use its buttons for the original purpose – as long as you keep your wiring job neat! When compared to reverse-engineering the protocol and using a wireless transmitter, this also has the benefit of being able to consistently work with even non-realtime devices like Raspberry Pi, and other devices that run an OS and aren’t able to guarantee consistent operation when driving a cheap GPIO-operated RF transmitter.

In the past, we’ve seen people trying to tackle this exact issue, resorting to RF protocol hacking in the end. We’ve talked about analog multiplexers and switches in the past, if you’d like figure out more ways to apply them to solve your hacking problems! Taking projects like these as your starting point, it’s not too far until you’re able to replace the drift-y joysticks on your Nintendo Switch with touchpads!

Ray's panels on the wall - circles of different sizes (from 60 to 15cm in diameter) covered by fabric of different shades, their arrangement vaguely resembling a cloud.

DIY Acoustic Panels Or Modern Artwork? Can’t Tell

January 31, 2022 by Arya Voronova 25 Comments

The acoustic properties of a room have a surprising impact when you want to use a microphone. [RayP24]’s son was trying to make his bedroom into a better recording studio, and for [Ray], that turned into an artfully-executed wall panel project. Fortunately, the process is documented so we all can learn from it. When it comes to acoustics, you can often get a whole lot of improvement from surprisingly few changes. And, as this project demonstrates, you can make it look like a decorative piece to boot.

When arranged and placed on the wall, these panels look like an art piece, a decoration you could get from a somewhat fancy store. If you show them to someone, they might not believe that they also serve as a functioning home acoustics improvement, dampening the sound quite well for audio recording needs. The panels are built out of individual circles, cut out in a way that uses as much of a 3/16″ (5mm) plywood sheet as possible, with hollow circles serving as frames to attach foam-backed fabric. In the Instructables post, [Ray] talks quite a bit about how you can assemble your own and what liberties you can take. There’s also a short video accompanying this project, which you can see after the break. This project is begging to be recreated.

There’s a sizeable amount of hacking-meets-home improvement-meets-home acoustics projects out there, especially lately, when so many people are stuck at home for one reason or another. Just a few months ago, we covered another marvelous “art piece turned reverb killer” project operating by a slightly different principle, and also going a bit more into the theory. Perhaps in a few years, we will no longer have to build panels or structures for our soundproofing needs, as purpose-grown mycelium shapes will do that for us. And once it becomes a question of where to hang your newly-built acoustic panels, this simple guide is a good place to start.

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Rainwater Storing Gojo Is A Stroke Of Genius

January 24, 2022 by Dave Rowntree 57 Comments

A traditional Ethiopian Gojo. Image courtesy of easterntravelandtour.com

The traditional Ethiopian Gojo is a circular domed dwelling constructed from a central vertical beam, and a surrounding structure of curved beams made from wood or bamboo. A covering of dried grass and mud completes the outer structure. These buildings are found everywhere in rural areas, due to their ease of construction, and availability of cheap materials. One major problem living in rural areas in developing countries is access to water. Ethiopian inventor [Anteneh Gashaw] knows a thing or two about the practicalities of living in a developing nation, and has come up with an ingenious take on the traditional Gojo. The idea is to replace the outer structure with pipes capable of storing rainwater. A collector plate on the top of the roof directs rain water into the pipes — with some small balancing tubes connecting them at the bottom — distributing the stored water evenly. A tap at the bottom of structure allows the pipes to be emptied on demand. Another interesting point about this design, is that the water adds some extra weight, for free, which gives the structure much improved stability in high winds, increasing safety.

{Anteneh] notes that proper water infrastructure is incredibly expensive, and just simply won’t happen. Well digging, installation of underground water tanks, and other such stop gap measures are great, but still need significant investment, and he believes that his modified Gojo idea will help reduce the problem of storing water during the rainy season, and reduce the pressure on centralised wells and other such community-orientated solutions. What’s more, it should be cheap. We shall watch with interest where this goes.

We’ve seen a few hacks from Africa nations, not many, just a few, but they are interesting ones. Like this DIY Helicopter that didn’t quite get to fly, and this e-waste 3D printer. We’ll keep our eye peeled for more!

Portable Pizza Oven Has Temperature Level Over 900

January 24, 2022 by Bryan Cockfield 36 Comments

While it’s possible to make pizza from scratch at home right down to the dough itself, it’ll be a struggle to replicate the taste and exquisite mouthfeel without a pizza oven. Pizzas cook best at temperatures well over the 260°C/500°F limit on most household ovens while pizza ovens can typically get much hotter than that. Most of us won’t have the resources to put a commercial grade wood-fired brick oven in our homes, but the next best thing is this portable pizza oven from [Andrew W].

The build starts with some sheet metal to form the outer and inner covers for the oven. [Andrew] has found with some testing that a curved shape seems to produce the best results, so the sheet metal goes through rollers to get its shape before being welded together. With the oven’s rough shape completed, he fabricates two different burners. One sits at the back of the oven with its own diffuser to keep the oven as hot as possible and the other sits underneath a cordierite stone to heat from the bottom. Both are fed gas from custom copper plumbing and when it fires up it reaches temperatures hot enough that it can cook a pizza in just a few minutes. With some foldable legs the oven also ends up being fairly portable, and its small size means that it can heat up faster than a conventional oven too.

This is [Andrew]’s third prototype oven, and it seems like he has the recipe perfected. In fact, we featured one of his previous versions almost two years ago and are excited to see the progress he’s made in this build. The only downside to having something like this would be the potential health implications of always being able to make delicious pizzas, but that is a risk we’d be willing to take.

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