Hackaday Prize 2022: Drying Clothes With Ultrasound

Clothes dryers are great, and a key part of modern life, but they do use a lot of energy. [Mike Rigsby] decided to see if there was a more efficient method of drying clothes that could compete with resistive heating for efficiency. Thus, he started work on an ultrasonic clothes dryer.

In early testing, he found ultrasonic transducers could indeed blast droplets of moisture away from fabric, effectively drying it. However, unlike heat, the ultrasonic field doesn’t effectively permeate through a pile of clothes, nor can it readily be used with a spinning drum to dry many garments at once.

[Mike]’s current experiments are centered around using a basket-type system, with a bed of ultrasonic transducers at the bottom. The idea is that the basket will shake back and forth, agitating the load of clothing and allowing the different garments to effectively contact the transducers. It’s still a work in progress, but it’s an interesting approach to the problem. We’d love to see a comparison of the energy use of a full-scale build versus a regular dryer.

We’ve heard of the ultrasonic drying concept before, too, with the Department of Energy researching the matter. It could just be that we’ll all be using ultrasonic dryers in decades to come!

Hackaday Prize 2022: Treadmill Becomes Human-Powered Generator

Running on a treadmill is a great way to workout, but what if the effort you put in could be put to use? This treadmill generator from [Amitabh Shrivastava] does just that.

The build starts with a regular old treadmill, which has a motor inside typically used to power the tread. Instead, the motor’s control electronics were removed, and it was repurposed to work as a generator. The output from the treadmill’s DC motor was fed directly to a DC-DC converter. This was then fed to an inverter that generates 120 V AC, which can power appliances that use up to 20-25W based on [tinkrmind’s] running performance.

It’s a fun way to generate power during a workout. If you don’t want your treadmill’s monitor to die in the middle of a Friends rerun, you’ll have to dig deep on those long runs. We’ve seen similar builds before too, with exercise bikes being a popular method of generating electricity. In fact, that’s [Amitabh]’s next project! Video after the break.

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Hackaday Prize 2022: A Cooler For Your Footwear

Sweaty feet can be uncomfortable, and the smell generated in one’s shoes isn’t much to admire, either. In an effort to help solve this issue, [Revoxdyna] has created a cooler for one’s feet that should help out in hot conditions.

Modern shoes, particularly sneakers, are often ventilated, but it’s not always enough. This build takes things further, using active cooling. Water is pumped through tubes and into a copper insole which cools the sole of the foot. It’s achieved thanks to a pump assembly that mounts to the rear of the shoe in a 3D printed housing. The water itself is chilled with a thermoelectric cooler, which helps remove heat from the shoe area.

There is some bulk to the design, which would prevent its use in performance applications in its current form. However, we could imagine companies like Nike leaping at the chance to build some very fancy, high-tech shoes along these lines in future. After all, they already managed to create power laces, and this is even cooler again! Pun definitely intended.

Robot Brutally Chops But Makes Poor Guacamole

Making guacamole by hand normally takes [Estefannie] about 9 minutes. Given her insatiable appetite for the delicious condiment, she spends a lot of time whipping it up in the kitchen at home. Thus, it’s a task ripe for automation, and she set about building a robot to do the job instead.

The robot starts by chopping ingredients like tomato, onion, and avocado with a knife that swivels to cover the entire chopping board surface. Once chopped, a sweeping blade pushes the ingredients into a bowl to form the guacamole.

Initial tests were messy, and ingredients were chopped a little inconsistently. Later work involved reprogramming the machine to chop ingredients separately, rather than all at once, which did improve the quality of the guacamole significantly. However, fundamentally, it wasn’t making good guac, so much as it was making a very chunky salad. It simply couldn’t do all the complicated jobs required to make a smooth, delicious dip.

[Estefannie] elected to instead let it live out its life as a mighty chopper, showing off its prowess by having it attack candy, cake, watermelon, and chocolate, which was pretty fun to watch. It bears noting that if you’re building a robot that swings a blade around, you need to be very careful. If you’re looking for something a bit safer, perhaps a Taco Bot is in your future.

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LEGO Rig Makes Pretty Water Vortexes

LEGO and its Technic line is a great way to learn about all kinds of mechanical things, but it’s also just a whole lot of fun to play with. We suspect the latter reason is what got [Brick Technology] to pursue creating a trippy water vortex with the building toy.

The first design uses a transparent plastic sphere as a water vessel. Inside the sphere is placed a small turbine, turned from the outside via a magnetic coupling. This means the sphere can remain intact, with no holes required, nor complicated seals which can leak. It works well, and produces a vortex when the turbine is spun by a regular LEGO motor. A second attempt elects to rotate the entire sphere itself. Small LEGO wheels are then used to hold the sphere in place on the rapidly spinning turntable. The results are impressive, creating a large and relatively well-formed vortex.

Naturally, though, the video saves the best for last. The big transparent sphere is installed in a rig that surrounds it completely. The sphere itself is spun up thanks to wheels installed on two different axes. This allows the sphere to be spun in various directions under command from a PlayStation controller, creating more complicated vortexes and flow patterns. A set of swiveling casters are provided to hold the sphere in place as it rotates in various directions, and are damped with springs and rubber bands to stop the rig shaking itself apart.

Is there much purpose to this? Well, not on the surface level, no. However, it would certainly make one heck of a rig for shaking up cocktails. Or, if for some reason you need a noisy yet attractive centrifugal separator, maybe this could do the trick. Continue reading “LEGO Rig Makes Pretty Water Vortexes” →

Powering A Cellphone With Gasoline

Batteries are a really useful way to store energy, but their energy density in regards to both weight and volume is disappointing. In these regards, they really can’t compete with fossil fuels. Thus, [bryan.lowder] decided to see if he could charge a phone with fossil fuels as safely and inoffensively as possible.

Obviously, with many national grids relying on fossil fuels for a large part of their generation, most of us are already charging our phones with fossil fuels to some degree. However, the aim here was to do so more directly, without incurring transmission losses from the long runs through the power grid. Continue reading “Powering A Cellphone With Gasoline” →

Hackaday Prize 2022: A Spring-Driven Digital Movie Camera

These days, most of us are carrying capable smartphones with high-quality cameras. It makes shooting video so easy as to take all the fun out of it. [AIRPOCKET] decided to bring that back, by converting an old spring-driven 8mm film camera to shoot digital video.

The camera in question is a magazine-fed Bell & Howell Model 172 from the 1950s. In its original spring-driven form, it could shoot for approximately 35 seconds at a (jerky) frame rate 16 fps.

In this build, though, the film is replaced with a digital imaging system designed to fit in the same space as the original magazine. A Raspberry Pi Zero 2 was pressed into service, along with a rechargeable battery and Pi camera module. The camera is timed to synchronise with the shutter mechanism via a photosensor.

Since it uses the original optics and shutter speed, the resulting video is actually very reminiscent of the Super 8 cameras of the past. It’s an impressive way to get a retro film effect straight into a digital output format. The alternative is to just shoot on film and scan it afterwards, of course! Video after the break.

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