solenoid

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Get Down To Some African Tunes With This HomeBrew Synth

December 5, 2021 by 9 Comments

South African [Afrorack] claims to have built the first home-built modular synthesiser in Africa. Whilst we can’t be sure of this (and to be frank, it doesn’t actually matter) what we can be sure of is that the latest additions to this rig sound pretty rad. (video, embedded below) There really isn’t much doubt that the African nations are the kings of rhythm, and that living in the less well-to-do areas you need to have a certain resourcefulness to use the materials around you. It’s not like you can just pop down to the local electronics store for a missing part, even if you had the funds for it.

The modular synth looks pretty nice, rough and ready like a real homebrew, and the use of an oil can as a bass drum and rice in a plastic skiff as an instrument might look crude, but sound pretty good. All three additions to the rig are simple spring-loaded solenoid affairs, but since off the shelf stuff is an expensive luxury, hand wound coils were in order. With a bobbin formed with a metal rod and two suitably trimmed fanta bottle lids, a wire spool holder sitting on what looks like a cake stand, a drill powered coil winder was constructed. We did smirk a little when in an early shot, wire was guided by hand, which was rapidly followed by an adjustment to guiding with a rag. Darn friction burns! We’re watching this with interest to see what the next additions will be, but for now, just sit back and nerd out to some sick African techno tunes!

Want to see a mess-o-wires turn into something meaningful? Got some Game Boys lying around needing something to do? How about a chiptune synth?

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A man using a homemade vacuum apparatus to climb a wall

Scale Buildings With The Power Of Suction

November 28, 2021 by 30 Comments

Walls can’t hold [Elijah Cirioli]. The would-be superhero has been busy scaling the sides of buildings using his self-contained vacuum climbers. (Video embedded after the break.)

After being inspired by the winning project of an Air Force design challenge, our plain-clothed crusader got to work on a pair of prototype vacuum climbers. The wooden prototypes were an unexpected success, so work soon began on the models featured in the video after the break. The main improvements in this second version included using ¼ inch acrylic instead of plywood, as well as an improved gasket for a better seal against the imperfect exterior of many building walls.

While the system would still ultimately struggle with brick walls (and other imperfect surfaces), it performs more than adequately when ascending smoother concrete walls. And while the acrylic was a far better choice than the plywood, one of the acrylic panels still developed a fracture. Even so, the results speak for themselves, and we have to applaud the inventor’s seemingly unconditional trust in his equipment.

We haven’t seen a follow-up from [Elijah Cirioli] recently, so here’s hoping that he’s busy working on version three, and that he’s not stuck up a wall somewhere. In the meantime, check out how someone accomplished similar wall-climbing feats using salvaged microwave transformers.

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Fake motivational plant squirts you in the wherever.

Focus Flower Motivates By Squirting Water In Your Face

November 4, 2021 by 4 Comments

When you need to get some tasks done and are short on attention, it’s hard to beat a timer. But whenever you do, it feels pretty darn good. The problem is that when you don’t finish in time, what’s the punishment? There are no consequences baked into the Pomodoro Technique other than good ol’ guilt. Wouldn’t it be better if there was a bit of negative reinforcement involved?

[Hardware Unknown]’s Focus Flower never needs watering, at least not in the normal horticultural way. You will have to fill a reservoir, because this flower provides liquid motivation. No, it’s not a spirit spritzer, though we suppose you could turn it into an avant-garde vodka fountain when the novelty of water wears off, making this Pomodoro with a twist into more of a Bloody Mary. It’s a natural next step, especially if you were already into the hot sauce idea.

Operation Focus Flower is simple: just push the easy button to start the task timer, and the Arduino Nano attached will begin a countdown. Push the button again when you’re done, but if you don’t do it before the countdown is over, the plant squirts you with a steady, skin-blasting stream of water from a solenoid-driven flosser tip. An air compressor nearby is required, which blows the minimalist vibe a bit, but you could always stow that part underneath your desk.

The Focus Flower sure looks to be effective at the whole negative reinforcement thing. And it doesn’t leave you totally clueless — there’s a ring of LEDs around the base that show how much time is left. Whenever you do successfully hit the button in time, it will say ‘that was easy’ in one of 12 languages, hence all the flags. Do not miss the totally free infomercial below.

Maybe you want a more friendly way to manage your time — we understand. Meet the Pomodachi productivity pet.

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A macro keypad making music.

Meet The Marvelous Macro Music Maker

September 23, 2021 by 1 Comment

Do you kind of want a macropad, but aren’t sure that you would use it? Hackaday alum [Jeremy Cook] is now making and selling the JC Pro Macro on Tindie, which is exactly what it sounds like — a Pro Micro-based macro keypad with an OLED screen and a rotary encoder. In the video below, [Jeremy] shows how he made it into a music maker by adding a speaker and a small solenoid that does percussion, all while retaining the original macro pad functionality.

[Jeremy]’s original idea for a drum was to have a servo seesawing a chopstick back and forth on the table as one might nervously twiddle a pencil. That didn’t work out so well, so he switched to the solenoid and printed a thing to hold it upright, and we absolutely love it. The drum is controlled with the rotary encoder: push to turn the beat on or off and crank it to change the BPM.

To make it easier to connect up the solenoid and speaker, [Jeremy] had a little I²C helper board fabricated. There’s one SVG connection and another with power and ground swapped in the event it is needed. If you’re interested in the JC Pro Macro, you can pick it up in various forms over on Tindie. Of course, you might want to wait for version 2, which is coming to Kickstarter in October.

There are many ways to make a macro keyboard. Here’s one that also takes gesture input.

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Can The Solenoid Engine Power A Car?

June 26, 2021 by 12 Comments

[Emiel] aka [The Practical Engineer] makes all kinds of fun projects in his fully-featured shop, and one of his tangents has been building a series of solenoid engines. These engines mimic the function of an internal combustion engine, with each solenoid acting as a piston. The only problem with [Emiel]’s concept engines, though, was that he never actually put them into a vehicle to prove their effectiveness. This build finally proves that they can work at powering a vehicle.

The project starts with a new engine. [Emiel] chose a V4 design using four solenoids and an Arduino-based controller. After some trouble getting it to operate properly, he scavenged a small circuit board he built in his V8 solenoid engine to help with timing. With that installed, the solenoids click away and spin the crankshaft at a single constant speed. The vehicle itself was mostly 3D printed, with two aluminum tubes as support structures to mount the engine. Even the wheels were 3D printed with a special rubber coating applied to them. With a small drive train assembled, it’s off to the races for this tiny prototype.

While the small car doesn’t have steering and only goes at a constant speed, the proof of concept that these tiny electric engines actually work is a welcomed addition to [Emiel]’s collection of videos on these curious engines. Of course they’re not as efficient as driving the wheels directly with an electric motor, but we all know there’s no fun in that. If you haven’t seen his most intricate build, the V8 is certainly worth checking out, and also shows off the timing circuitry he repurposed for this car.

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Feel What The Temperature Is Like Outside Without Leaving Your Bed

May 4, 2021 by 17 Comments

Your smartphone might be able to tell you what the weather is like outside, but you’d have to go outside yourself to really feel it. To do this from the comfort of your own bed, [Sagarrabanana] built a clock that lets you really feel the temperature. Video below with English subtitles.

It is basically a box with a solenoid inside to knock out the time, and a Peltier plate on top. Give the box two knocks, which are detected by a piezo element,  and it will tell you the current time down to 15 minute increments in “bell tower” format. Give it three knocks, and the ESP8266 will fetch the ambient outside temperature from a cloud service and cool or heat the Peltier element to that temperature, using a H-bridge motor driver module. The code and design files are available on GitHub if you want to build your own.

All the components are housed inside an attractive 3D printed box with a machined wood top. Although we think this is a very interesting idea, we can’t help but suspect that it might be counterproductive for getting you out of bed on those cold winter mornings.

While alarm clocks are falling out of favor, they are still a popular build for hackers. We’ve covered one that looks like it came from a fallout shelter, and another with a very cool looking VFD display. Continue reading “Feel What The Temperature Is Like Outside Without Leaving Your Bed” →

Build An ESP32 Stock Ticker To Watch Your GME Gains

April 26, 2021 by 14 Comments

Meme investing is all the rage these days, and what better way to get in on the loss fun than with your very own old-timey mechanical stock ticker? Unfortunately, they’re about as expensive and rare as you might expect for a piece of Victorian-era electronics. Lucky for us, [secretbatcave] has shown that you can put together a functional look-alike that costs about as much as a GameStop (GME) share was worth before it started heading to the Moon.

This might seem like an ambitious project, but in actuality the machine only has a few moving parts. There’s a stepper motor to feed the paper, another to spin an inked embossing wheel, and a couple of solenoids attached to a pusher plate. Rather than trying to move the heavy wheel, the pusher plate smashes the paper up into it. The fact that this produces a satisfying “clack” sound as each character is printed is just an added bonus.

Extending the base to hold the solenoids.

To sell the look, [secretbatcave] put the whole mechanism inside a tall glass dome from IKEA. The matching wooden base was extended so the pusher plate solenoids could fit inside, after which it was dunked in ink and sprayed with a gloss sealer to give it that shiny black finish people seemed to love in the 1900s. With the addition of an engraved brass nameplate, it looks like the machine fell out of a time warp.

In terms of electronics, there’s an ESP32, a pair of stepper motor controllers, and a relay for the solenoids. As of right now it all lives in a rather utilitarian box that’s tethered to the ticker, but we’re sure the lot could get tucked under the base with the help of a custom PCB should you be so inclined.

With an ESP32 at the helm, the ticker could easily be configured to print out whatever data it receives over the network or picks up from MQTT. With hardware like this and a pair of Diamond Hands, those tendies are as good as yours.

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