solenoid

146 Articles

In This Aussie’s Back Yard, No Cat Is Safe From An Automated Soaking!

May 14, 2019 by 32 Comments

Some of us here at Hackaday are cat lovers, but we also understand that a plethora of unwanted cats using a suburban back garden can be bothersome, and a few years ago we featured a project from Aussie YouTuber [Craig Turner], in which he created a motion-detecting water spray for use as a relatively harmless cat repellent. Now he’s back with an updated version which is a little slicker and easier to make.

At its heart is the same PIR-turns-on-water operation, but this time there is a solenoid valve and purpose-built nozzle instead of a car central locking actuator and a lawn sprayer. Doing the electronic work is an off-the-shelf PIR module, so there is no  longer any need to hack a security PIR detector. Add in some pipe sections and PTFE tape with a bit of hot glue, and the result is a far more professional and streamlined device. The video gives a full run-down on construction, though we notice he neglected to emphasise the polarity of his protection diode so keep an eye out if you follow his example.

So if the thought of a continuous supply of free feline company courtesy of your neighbours is not for you then now you are equipped to send them packing. The latest video incarnation of the project is below the break, but if you are in search of the original then you can go back to our coverage at the time.

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Air Bubble Characters Float Along This Unique Scrolling Display

November 30, 2018 by 16 Comments

We’ve seen a lot of unique large-format scrolling message boards on these pages, but most of them use some sort of established technology – LEDs, electromechanical flip-dots, and the like – in new and unusual ways. We’re pretty sure this air-bubble dot matrix display is a first, though.

While it may not be destined for the front of a bus or a train station arrivals and departures board, [jellmeister]’s bubble display shows some pretty creative thinking. It started with a scrap of multiwall polycarbonate roofing – Corotherm is the brand name – of the type to glaze greenhouses and other structures. The parallel tubes are perfect for the display, although individual tubes could certainly be substituted. A plastic end cap was fabricated; air nozzles in each channel were plumbed to an air supply through solenoid valves. An Arduino with a couple of motor driver hats allows pulses of air into each channel to create reasonably legible characters that float up the tube. The video below shows it in use at a Maker Faire, where visitors could bubble up their own messages.

It took some tweaking to get it looking as good as it does, but there’s plenty of room for improvement. We wonder whether colored liquid might help, or perhaps adding a Neopixel or even a laser to each channel to add some contrast. Maybe something to cloud the water slightly would help; increasing the surface tension with a salt solution might make the bubbles more distinct. We doubt it’ll ever have the contrast ratio of a flip-dot display, but it certainly has a charm all its own.

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Retro Wall Phone Becomes A Doorbell, And So Much More

November 20, 2018 by 5 Comments

We have to admit that this retasked retro phone wins on style points alone. The fact that it’s filled with so much functionality is icing on the cake.

The way [SuperKris] describes his build sounds like a classic case of feature creep. Version 1 was to be a simple doorbell, but [SuperKris] would soon learn that one does not simply replace an existing bell with a phone and get results. He did some research and found that the ringer inside the bakelite beauty needs much more voltage than the standard doorbell transformer supplies, so he designed a little H-bridge circuit to drive the solenoids. A few rounds of “while I’m at it” later, the phone was stuffed with electronics, including an Arduino and an NFR24 radio module that lets it connect to Domoticz, a home automation system. The phone’s rotary dial can now control up to 10 events and respond to alarms and alerts with different ring patterns. And, oh yes – it’s a doorbell too.

In general, we prefer to see old equipment restored rather than gutted and filled with new electronics. But we can certainly get behind any effort to retask old phones with no real place in modern telecommunications. We’ve seen a few of these before, like this desk telephone that can make cell calls.

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Dymo Rides Again With This Dot-Matrix Label Embosser

October 13, 2018 by 21 Comments

For a five-year-old future Hackaday scribe, there could be no greater day than that on which a Dymo label maker appeared in the house. With its spinny daisy-wheel to choose a character and its squeezy handle to emboss the letter into the plastic tape, there would follow a period of going nuts kerchunking out misspelled labels and slapping them on everything. Plus the things look like space guns, so there would have been a lot of pew-pewing too.

This Dymo dot-matrix label maker bears no resemblance to our long-lost label blaster, but it’s pretty cool in its own right. The product of collaborators [Felix Fisgus] and [Timo Johannes] and undertaken as a project for their digital media program, the only thing the labeler has in common with the Dymos of old is the tape. Where the manual labelers press the characters into the tape with a punch and die, their project uses a dot-matrix approach. Messages are composed on an old PS/2 keyboard through an Arduino and a 16×2 LCD display, and punched onto the tape a dot at a time. The punch is a large darning needle riding on the remains of an old CD drive and driven by a solenoid. When it comes time to cut the label, servo driven scissors do the job. It’s a noisy, crazy, Rube Goldberg affair, and we love it. Check it out in action in the video below.

We applaud [Felix] and [Timo] for carrying the torch of embossed label making. It’s a shame that we’ve turned to soulless thermal printers to handle most of our labeling needs; then again, we’ve seen some pretty neat hacks for those too.

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Let No Eyebrow Go Unsinged With A Wrist-Mounted Flamethrower

September 14, 2018 by 10 Comments

We’ll say it just once, and right up front: wrist-mounted flamethrowers are a bad idea. An itchy nose and a brief moment of forgetfulness while sporting one of these would make for a Really Bad Day. That said, this flaming gauntlet of doom looks like a lot of fun.

We’ve got to hand it to [Steve Hernandez] – he put a lot of work into the Flame-O-Tron 9000. Building on his prior art in the field, [Steve] went a bit further with this design. The principle is the same – butane plus spark equals fun – but the guts of this flamethrower are entirely new. A pipe bomb custom fuel tank is used rather than the stock butane can, and a solenoid valve controls fuel flow. Everything lives in a snazzy acrylic case that rides on a handmade leather bracer, and controls in the hand grip plus an Arduino allow the user to fire short bursts of flame or charge up for a real fireball. See what you think of the final product in the short video after the break; it sounds as though even if the fuel runs out, the high-voltage would make a dandy stun gun.

Maybe we should lay off the safety nagging on these wrist rockets. After all, we’ve seen many, many, many of them, with nary a report of injury.

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See The Fabulous Workmanship In This Smart Pressure Regulator

August 28, 2018 by 8 Comments

For many projects that require control of air pressure, the usual option is to hook up a pump, maybe with a motor controller to turn it on and off, and work with that. If one’s requirements can’t be filled by that level of equipment and control, then it’s time to look at commercial regulators. [Craig Watson] did exactly that, but found the results as disappointing as they were expensive. He found that commercial offerings — especially at low pressures — tended to leak air, occasionally reported incorrect pressures, and in general just weren’t very precise. Out of a sense of necessity he set out to design his own electronically controlled, closed-loop pressure regulator. The metal block is a custom manifold with valve hardware mounted onto it, and the PCB mounted on top holds the control system. The project logs have some great pictures and details of the prototyping and fabrication process.

This project was the result of [Craig]’s work on a microfluidics control system, conceived because he discovered that much of the equipment involved in these useful systems is prohibitively expensive for small labs or individuals. In the course of developing the electronic pressure regulator, he realized it could have applications beyond microfluidics control, and created it as a modular device that can easily be integrated into other systems and handle either positive or negative pressure. It’s especially well-suited for anything with low air requirements and a limited supply, but with a need for precise control.

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Sushi-Snarfing Barbie Uses Solenoid To Swallow

August 7, 2018 by 15 Comments

The view from America has long seen French women as synonymous with thin and/or beautiful. France is well-known for culinary skill and delights, and yet many of its female inhabitants seem to view eating heartily as passé. At a recent workshop devoted to creating DIY amusements, [Niklas Roy] and [Kati Hyyppä] built an electro-mechanical sushi-eating game starring Barbie, American icon of the feminine ideal. The goal of the game is to feed her well and inspire a happy relationship with food.

Built in just three days, J’ai faim! (translation: I’m hungry!) lets the player satiate Barbie one randomly lit piece of sushi at a time. Each piece has a companion LED mounted beneath the surface that’s connected in series to the one on the game board. Qualifying sushi are determined by a photocell strapped to the underside of Barbie’s tongue, which detects light from the hidden LED. Players must race against the clock to eat each piece, taking Barbie up the satisfaction meter from ‘starving’ to ‘well-fed’. Gobble an unlit piece, and the score goes down.

The game is controlled with a lovely pink lollipop of a joystick, which was the main inspiration for the game. Players move her head with left and right, and pull down to engage the solenoid that pushes her comically long tongue out of her button-nosed face. Barbie’s brain is an Arduino Uno, which also controls the stepper motor that moves her head.

[Niklas] and [Kati] wound up using cardboard end stops inside the box instead of trying to count the rapidly changing steps as she swivels around. The first motor they used was too weak to move her head. The second one worked, but the game’s popularity combined with the end stops did a number on the gears after a day or so. Click past the break to sink your teeth into the demo video.

Barbie can do more than teach young girls healthy eating habits. She can also teach them about cryptography.

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