Misc Hacks

4137 Articles

Reon Pocket Keeps You Cool With A Peltier Element

August 1, 2019 by 53 Comments

With another summer of heatwaves leaving its mark on our planet, finding a way to stay cool during the day isn’t an easy task. From the morning and afternoon commute in public transport, to busy crowds outside during lunch hour, there are many times when you cannot just find a place inside an airconditioned room to deal with the heat. Exactly for this purpose Sony has successfully completed a kickstarter (in Japanese) on its corporate ‘First Flight’ crowdfunding platform for the Reon Pocket.

Many people probably aren’t aware of Sony’s crowdfunding platform, but it’s a way to gauge the interest from the public for more ‘out there’ products, which do not fit Sony’s usual business model. In this case the Reon Pocket is a Peltier-based device which is placed against the back of one’s neck, from where it can either lower or increase the body’s temperature, reportedly by -13 ℃ and +8.3 ℃ respectively.

Covered in more detail by Engadget and its Japanese sister site, the reported 24 hour battery life refers to the Bluetooth link that connects the device with one’s smartphone, whereas the battery lasts under two hours with the peltier element active. This is probably not too shocking to anyone who knows how a peltier element functions, and how much electricity they consume.

Still, the basic concept seems sound, and there are functioning prototypes. While a 2-hour battery life isn’t amazingly long, it can be just the thing one needs to keep one’s cool during that 15 minute walk to the office in a three-piece suit, without needing a shower afterwards. The device isn’t expensive either, with a projected ¥12,760 (about $117) supplied. Naturally the device will only be on sale in Japan.

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Lego-Powered Sub Built In A Water Jug

July 28, 2019 by 16 Comments

Submarines are universally considered cool, but bring several challenges to the RC modeller that aren’t there with land and air builds. Water ingress can ruin your project, and there’s always the possibility of it sinking to the bottom, never to return. That didn’t phase [Brick Experiment Channel], however, and thus a Lego sub was born. (Video embedded below the break.)

The sub uses a water jug as a hull. The video steps through the process of sealing the hull itself, before dealing with sealing the rotating propeller shafts. A large syringe is used as a ballast tank, with Lego motors used to actuate the tank and provide propulsion and steering. An existing RC submarine is cannabilized for parts, providing the necessary radio control hardware.

In testing, the sub performs admirably, with a few final tweaks necessary to improve the performance of the propellers. It’s not winning any races anytime soon, but it’s a functional underwater explorer that we’d love to take down the lake ourselves sometime.

We’ve seen Lego subs built before, even including missiles.

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Popstick Fan Car Is A Fun Bluetooth Build

July 25, 2019 by 5 Comments

Archer fans already know, but for the rest of the world it bears saying – boats are fine, but fan boats are better. It’s much the same with land vehicles, too. [tinkeringtech] felt the same way, and built a Bluetooth-controlled fan car to scoot around the floor. (YouTube, embedded below.)

Construction starts with a series of popsticks glued together to create a chassis. Twist ties are then used to act as axles for bottle cap wheels, while steering is handled by a cardboard rudder controlled by a servo. Propulsion is via a pair of pager-sized motors fitted with fans. An Adafruit Bluefruit Feather M0 runs the show, receiving commands over Bluetooth and driving the motors through an H-bridge chip in the center of the vehicle.

It’s a fun craft-style build that would be a great project for kids interested in electronics and making. It teaches basic electronics, as well as serving as a good introduction into the world of microcontrollers. It’s one of the smaller radio-controlled builds we’ve seen, but you can always go full-scale if that takes your fancy.

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Reaction Trainer Keeps You On Your Toes

July 24, 2019 by 1 Comment

In many sports, it’s important for competitors to be light on their feet, and able to react quickly to external stimuli. It all helps with getting balls in goals, and many athletes undergo reaction drills as part of their training regime. To help with this, [mblaz] set out to build a set of reaction trainers.

The training setup consists of a series of discs, each with glowing LEDs and a proximity sensor. The discs randomly light up, requiring a touch or wave to switch them off. At this point, another disc will light randomly, and so on.

The discs are built using an ATmega328 to run the show, with NRF24L01+ radios used to communicate between the modules. High brightness red LEDs are used for indication. An optical proximity sensor is used for its fast reaction time and low cost, while power comes via a small lithium polymer battery integrated into each disc.

We’re sure [mblaz] and his fellow athletes will find the rig to be useful in their training. There’s plenty of scope for electronics to help out with athletic training; this boxing trainer is a great example. If you’ve got a great sports engineering project of your own, don’t hesitate to send it in!

The Great Moon Hoax — No Not That One!

July 23, 2019 by 65 Comments

Humans first walked on the moon 50 years ago, yet there are some people who don’t think it happened. This story is not about them. It turns out there was another great conspiracy theory involving a well-known astronomer, unicorns, and humanoids with bat wings. This one came 134 years before the words “We chose to go to the moon” were uttered.

The 1835 affair — known as the Great Moon Hoax — took the form of six articles published in The Sun, a newspaper in New York City. Think of it like “War of the Worlds” but in newspaper form — reported as if true but completely made up. Although well-known astronomer John Herschel was named in the story, he wasn’t actually involved in the hoax. Richard Adams Locke was the reporter who invented the story. His main goal seemed to be to sell newspapers, but he also may have been poking fun at some of the more outlandish scientific claims of the day.

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Vacuum Sputtering With A Homemade Magnetron

July 23, 2019 by 8 Comments

“You can never be too rich or too thin,” the saying goes, and when it comes to coatings, it’s true that thinner is often better. The way to truly thin coatings, ones that are sometimes only a few atoms thick, is physical vapor deposition, or PVD, a technique where a substance is transformed into a vapor and condensed onto a substrate, sometimes using a magnetron to create a plasma.

It sounds complicated, but with a few reasonable tools and a healthy respect for high voltages, a DIY magnetron for plasma sputtering can get you started. To be fair, [Justin Atkin] worked on his setup for years, hampered initially by having to settle for found parts and general scrap for his builds. As with many things, access to a lathe and the skills to use it proved to be enabling, allowing him to make custom parts like the feedthrough for the vacuum chamber as well as a liquid-cooled base, which prevents heat from ruining the magnets that concentrate the plasma onto the target metal. Using a high-voltage DC supply made from old microwave parts, [Justin] has been able to sputter copper films onto glass slides, with limited success using other metals. He also accidentally created a couple of dichroic mirrors by sputtering with copper oxides rather than pure copper. The video below has some beautiful shots of the ghostly green and purple glow.

A rig such as this opens up a lot of possibilities, from optics to DIY semiconductors. It may not be quite as elaborate as some PVD setups we’ve seen, but we’re still pretty impressed.

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Making Flexible Overmolded Parts With Urethane Resin

July 19, 2019 by 11 Comments

Resin casting videos have taken social media by storm of late. Everything from inlaid driftwood tables to fancy pens are getting the treatment. Pouring some nicely colored epoxy is straightforward enough, but it’s just the tip of the iceberg. [Eric Strebel] has some serious skills in resin casting, and has lately been working on some overmolded electroniics with urethane resin (Youtube link, embedded below).

The build starts with the creation of a silicone mold, using a 3D printed SLA master. The part in question is for a prototype medical device, and requires overmolding, in which a flexible PCB is covered in flexible urethane. Wooden pins are used to allow the flexible PCB to clip into the mold for accurate location, and a small shield is placed over the metal contacts of the PCB to avoid them being covered in silicone.

Initial tests are done with an empty mold to determine the correct material to use, before the actual parts are ready to produce. [Eric] takes great care with the final production, as any mistakes would waste the expensive prototype PCBs provided to him by the client. With the electronics placed in the mold, the resin is degassed and carefully injected, using a syringe to minimise the chance of any air bubbles. With some delicate cleanup by hand, the completed parts are ready for delivery.

It’s a process that covers the basics of overmolding for a prototype part, as well as showing off [Eric]’s skill at producing quality prototype parts. We’ve seen [Eric]’s work before, too – like his discussion of the value of cardboard in product design. Video after the break.

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