Automated musical instrument with LED array

ESP32 Is The Brains Behind This Art Installation

The ESP32 has enabled an uncountable number of small electronics projects and even some commercial products, thanks to its small size, low price point, and wireless capabilities. Plenty of remote sensors, lighting setups, and even home automation projects now run on this small faithful chip. But being relegated to an electronics enclosure controlling a small electrical setup isn’t all that these tiny chips can do as [Eirik Brandal] shows us with this unique piece of audio and visual art.

The project is essentially a small, automated synthesizer that has a series of arrays programmed into it that correspond to various musical scales. Any of these can be selected for the instrument to play through. The notes of the scale are shuffled through with some random variations, allowing for a completely automated musical instrument. The musical generation is entirely analog as well, created by some oscillators, amplifiers, and other filtering and effects. The ESP32 also controls a lighting sculpture that illuminates a series of LEDs as the music plays.

The art installation itself creates quite haunting, mesmerizing tunes that are illustrated in the video linked after the break. While it’s not quite to the realm of artificial intelligence since it uses pre-programmed patterns with some randomness mixed in, it does give us hints of some other projects that have used AI in order to compose new music.

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A Nerf Gun Upgrade

A lot of us have nostalgia for our childhood toys, and as long as they’re not something like lawn darts that nostalgia often leads to fun upgrades since some of us are adults with industrial-sized air compressors. Classics like Super Soakers and Nerf guns are especially popular targets for improvements, and this Nerf machine gun from [Emiel] is no exception.

The build takes a Nerf ball-firing toy weapon and basically tosses it all out of the window in favor of a custom Nerf ball launching rifle. He starts with the lower receiver and machines a pneumatic mechanism that both loads a ball into the chamber and then launches it. This allows the rifle to be used in both single-shot mode and also in fully-automatic mode. From there, a barrel is fashioned along with the stock and other finishing touches.

[Emiel] also uses a high-speed camera to determine the speed of his new Nerf gun but unfortunately it isn’t high-speed enough, suffering from the same fate as one of the fastest man-made objects ever made, and he only has a lower bound on the speed at 400 km/h. If you don’t want to go fast with your Nerf builds, though, perhaps you should build something enormous instead. Continue reading “A Nerf Gun Upgrade”

Voice Controlled Sofa Meets Your Every Beverage Need

It’s often taken for grated, but the modern world is full of luxuries. Home automation, grocery delivery, and even access to the Internet are great tools to have at hand, but are trivial to most of us. If these modern wonders are not enough for you, and the lap of luxury is still missing a certain je ne sais quoi, allow us to introduce you to the ultimate convenience: a voice controlled, beer-dispensing sofa with a built-in refrigeration system.

This is a project from [Garage Avenger] and went through a number of iterations before reaching this level of polish. Metal work on the first version didn’t fit together as expected, and there were many attempts at actual refrigeration before settling on repurposing an actual refrigerator. With those things out of the way, he was able to get to the meat of a project. The couch-refrigerator holds 12 beers, and they are on a conveyor belt which automatically places the next beer onto the automated drawer. When commanded (by voice, app, or remote) the sofa opens the drawer so the occupant can grab one easily without having to move more than an arm. Everything, including the voice recognition module, is controlled by an Arduino, as is tradition.

The attention to detail is excellent as well. The remote control contains a built-in bottle opener, for one, there are backlights and a glass cover for the refrigerator, and the drawer is retracted automatically when it senses the beer has been obtained. We couldn’t ask for much more from our own couches, except maybe that they take us where we want to go. But maybe it’s best to keep these two couch use cases separate for now.

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Building A Sound Activated Shop Fan With Arduino

Whether you’re using a soldering iron or a table saw, ventilation in the shop is important. Which is why [Atomic Dairy] built a monster air cleaner called the Fanboy that looks like it should be mounted under the wing of an F-15. Realizing a simple switch on the wall wouldn’t do this potent air mover justice, they decided to build a sound activated controller for it.

It’s certainly an elegant idea. The sound created once they kick on their woodworking tools would be difficult to miss by even the most rudimentary of sound-detection hardware. At the most basic level, all they needed was a way for an Arduino to throw a relay once the noise level in the room reached a specific threshold.

Of course it ended up getting a bit more complicated than that, as tends to happen with these kinds of projects. For one, the sound doesn’t directly control the solid state relay used in the fan controller. When the microphone equipped Arduino detects enough noise, it will start a timer that keeps the fan running for two hours. If the tool keeps running, then more time gets added to the clock. This ensures that the air in the room is well circulated even after the cutting and sanding is done.

[Atomic Dairy] also added a few additional features so they could have more direct control over the fan. There’s a button to manually add more time to the clock, and another button to shut it down. There’s even support for a little wireless remote control, so the fan can be operated without having to walk over to the control panel.

We’ve seen some impressive air circulation and dust collection systems over the years, but finding a way to elegantly switch them on and off has always been a problem given the wide array of tools that could be in use at any given time. Sound activation isn’t a perfect solution, but it’s certainly one we’d consider for our own shop.

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Detecting Cars With An ESP8266 Magnetometer

Having a motorized gate on your driveway is great, but only if there’s an easy way to trigger it. [Andrew] says the gate at his parent’s place could only be controlled by manually pushing a button on the panel or with a dinky remote that didn’t have nearly the range they wanted. So he decided to build his own magnetometer allowing the gate to automatically open when a car was trying to leave.

Naturally, there are commercial offerings that would solve this problem. But with a sticker price of more than $150 USD, [Andrew] was more than happy to spend a bit of time tinkering to get the job done for less than 1/10th the cost with an ESP8266 and a QMC5883X series magneto-resistive sensor. Of course, this is one of those projects that seems simple enough in your head, but ends up taking a bit of finesse to pull off in the real-world.

For one, [Andrew] had to figure out how to prevent false positives. Pretty much any object brought close enough to the sensor, including his hand, would cause it to react. He ended up coming up with a way to use a rolling average to prevent the gate from firing off just because a squirrel ran past. The built-in safeties are designed to ensure that the gate only opens when an actual car is sitting in the appropriate spot for long enough.

Speaking of, we love how [Andrew] deployed the QMC5883X sensor for this project. The small sensor board and a few moisture-absorbing packets were placed in a Sonoff IP66 waterproof enclosure, and buried under the rocks of the driveway. A standard CAT5 cable is used to tether it to the ESP8266, relay, and assorted other goodies that now live in the gate’s control box. In the future he says the cable will likely have to go into a conduit, but for now the system is working more or less how he expected.

If your estate isn’t quite palatial enough to have a motorized gate out front, we’ve seen plenty of projects that add some much-needed intelligence to the humble garage door opener which might be more your speed.

Put The 3D Printer To Sleep So You Can Rest Easy

At this point you’ve probably already heard the news: cheap Chinese 3D printers sometimes catch fire. Now we can’t say we’re shocked to find out that absolute bottom of the barrel gear wasn’t designed to the highest standards (gotta cut those corners someplace), but that doesn’t change the fact that there are thousands of hackers and makers out there who are in possession of one of these suspect machines. Just tossing them to the curb is hardly the hacker way, so we’ve got to find ways to make the best of the hand dealt to us.

After sleeping with one eye (and maybe one nostril) open during some overnight prints, Hackaday.io user [TheGrim] wanted a way to make sure his Alunar Anet A6 didn’t stay powered on any longer than necessary. So he came up with a way of using the printer’s own endstop switch to detect if the print has completed, and cut the power.

The idea is simple, but of course the real trick is in the implementation. By adding a “Home” command to his ending G-Code in Cura, [TheGrim] reasoned he could use the Y endstop switch to determine if the print had completed. It was just a matter of reading the state of the switch and acting on it.

In the most basic implementation, the switch could be used to control a relay on the AC side of the power supply. But [TheGrim] doesn’t trust relays, and he wanted to pack in a couple “smart” features so he ended up using a PIC microcontroller and two 12 amp TRIACs. There’s also a couple of LEDs and toggle switches to serve as the user interface, allowing you to enable and disable the automatic shutdown and get status information about the system.

Will cutting the juice to the PSU prevent another terrible fire? It’s debatable. But it certainly can’t hurt, and if it makes [TheGrim] feel more confident about running his machine, then so be it. We’d still advise anyone with a 3D printer at home to brush up on their fire safety knowledge.

Push Button, Receive Beverage!

Here’s a rec-room ready hack: an automatic drink dispenser.

[truebassB]’s dispenser operates around a 555 timer, adjusted by a potentiometer. Push a button and a cup pours in a few seconds, or hold the other button to dispense as much as you want.

The dispenser is made from MDF and particle board glued together, with some LEDs and paper prints to spruce it up. Just don’t forget a small spill sink for any miscalculated pours. You needn’t fret over the internals either, as the parts are easily acquired: a pair of momentary switches, a 12V micro air pump, a brass nozzle, food-safe pvc tube,  a custom 555 timing circuit — otherwise readily available online — a toggle switch, a power supply plug plus adapter and a 12V battery.

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