Welding Batteries With Batteries

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Welding equipment is always expensive and bulky, right? Heavens no! [Jaromir Sukuba] is making a welder for battery tabs which can fit in a pocket and gets its power from a coin cell. It may be expensive to power compared to a mains welder, but for the sake of portability this is quite the hack. Not only that, but it uses 555 timers in the charging circuit.

His entry for the 2017 Coin Cell Challenge saps every bit of power from a coin cell and stores it up in a 100F supercapacitor bank. All that stored energy takes a long …read more

A Watch Only A Ham Can Use

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We’re not sure what to make of this one. With the variety of smartwatches and fitness trackers out there, we can’t be surprised by what sort of hardware ends up strapped to wrists these days. So a watch with an RPN calculator isn’t too much of a stretch. But adding a hex editor? And a disassembler? Oh, and while you’re at it, a transceiver for the 70cm ham band? Now that’s something you don’t see every day.

The mind boggles at not only the technical prowess needed to pull off what [Travis Goodspeed (KK4VCZ)] calls the GoodWatch, but at the …read more

A Gloriously Impractical Electromechanical Display

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For this year’s office holiday party, [Gavan Fantom] wanted to do something really special. Coworkers were messing with LEDs to come up with displays and decorations, but they lack that old-school feel of mechanical displays. He wanted to create something that had retro look of moving elements, but didn’t want to just recreate the traditional flip mechanism we’ve all seen over and over.

What [Gavan] came up with is breathtakingly impractical 8×8 display that sounds as cool as it looks. Each “pixel” in the display is a 3D printed screw mechanism rotated by a hobby servo. As the pixel is …read more

Stromberg Carlson Charactron Tube

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Flat panel TVs have spoiled us. It used to be that a big display took up a lot of room on your desk or living room because of the depth of the CRT’s electron gun. We wonder what the designers of the charactron would think if they could see our big flat screens today. Never heard of a charactron? Check out [uniservo’s] video of one of these old character display tubes.

You might think the device is just a simple small CRT. However, it is much stranger than that. Inside the tube was a stencil that contained all the characters …read more

DRM Workarounds Save Arcade Cabinet

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DRM has become a four-letter word of late, with even media companies themselves abandoning the practice because of how ineffective it was. DRM wasn’t invented in the early 2000s for music, though. It’s been a practice on virtually everything where software is involved, including arcade cabinets. This is a problem for people who restore arcade machines, and [mon] has taken a swing at unraveling the DRM for a specific type of Konami cabinet.

The game in question, Reflec Beat, is a rhythm-based game released in 2010, and the security is pretty modern. Since the game comes with a HDD, a …read more

Geocache Locator Is The Gift That Keeps On Giving

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Depending on how you look at things, the holidays could be seen as either an excuse to spend money or an excuse to get creative. We imagine many Hackaday readers would rather head to their workbench than the mall when it comes time for gift giving, and [Sean Hodgins] is no different. He came up with the idea of hiding geocaches around his nephew’s neighborhood and building him a locator device to find them. The locator itself is intended to grow with his nephew, allowing him to reprogram it or use its parts for something completely different down the road. …read more

There are 10 Kinds of Computers in the World

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There’s an old joke that there are 10 kinds of people in the world. Those who know binary, those who don’t, and those who didn’t see a base three joke coming. Perhaps [Dmitry Sokolov] heard that joke because he’s built a ternary (base 3) computer. He claims it is the first one to be built in the last 50 years. You can see a video about the device below. There’s also a video of the device with a nixie tube output.

You may not think of it often, but bit is a contraction of binary digit, so a ternary computer …read more

Frankendrones: Toy Quads With A Hobby Grade Boost

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If you’re not involved in the world of remote controlled vehicles, you may not know there’s a difference between “toy” and “hobby” grade hardware. For those in the RC community, a toy is the kind of thing you’ll find at a big box store: cheap, works OK, but lacking in features and build quality. On the other hand, hobby hardware is generally considered to be of higher quality and performance, as well as being more modular. At the risk of oversimplification: if you bought it ready to go from a store it’s probably a toy, and if you built it …read more

3D Printed Key Saves the Day

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When [Odin917’s] parents went away on vacation, they took the apartment mailbox key with them. With the mail quickly piling up in the mailbox, he needed to get in there. He could have had the building super replace the lock, for a fee of course. Instead he had his parents email a photo of the key, which he used to 3D print his own copy.

Using a photograph as a template for a 3D printed copy is nothing new. We’ve covered it in-depth right here. However, this is the first time we’ve seen the technique put to use for good …read more

How Provably Loaded Dice Lead to Unprovable Cheating

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Here’s a really interesting writeup by [Mike] that has two parts. He shows that not only is it possible to load wooden dice by placing them in a dish of water, but that when using these dice to get an unfair advantage in Settlers of Catan, observation of dice rolls within the game is insufficient to prove that the cheating is taking place.

[Mike] first proves that his pair of loaded dice do indeed result in a higher chance of totals above seven being rolled. He then shows how this knowledge can be exploited by a Settlers of Catan …read more

Books You Should Read: The 3D Printing Handbook

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3D printing was invented in the 80s, twenty years passed, patents expired, and then several diverse uses for 3D printing technology were found. As such, the tips and techniques for 3D printing — especially filament-based printing — have been discussed and documented almost entirely on the Internet, mostly in chat rooms, forums, and YouTube videos. Everything you could ever want to know about 3D printing is available on the Internet, but that doesn’t mean you’ll be able to find it.

There have been dozens of books published as a guidebook to 3D printing over the years, and some of those …read more

A Dynamometer For Measuring Motor Power

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If you have ever ventured into the world of motor vehicles you may be familiar with a dynamometer, possibly as a machine to which your vehicle is taken for that all-important printout that gives you bragging rights (or not) when it comes to its ability to lay down rubber. A dynamometer is essentially a variable load for a rotating shaft, something that converts the kinetic energy from the shaft into heat while measuring the power being transferred.

Most of us will never have the chance to peer inside our local dyno, so a term project from a group of Cornell …read more

Small Jet Engine Model From Students Who Think Big

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We love to highlight great engineering student projects at Hackaday. We also love environment-sensing microcontrollers, 3D printing, and jet engines. The X-Plorer 1 by JetX Engineering checks all the boxes.

This engineering student exercise took its members through the development process of a jet engine. Starting from a set of requirements to meet, they designed their engine and analyzed it in software before embarking on physical model assembly. An engine monitoring system was developed in parallel and integrated into the model. These embedded sensors gave performance feedback, and armed with data the team iterated though ideas to improve their design. …read more

Machined Lightsaber Pen for a More Civilized Age

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In an increasingly paperless society, writing implements are becoming an obsolete technology for many of us. Certainly not the kind of thing the average person would think to spend more than a couple bucks on, to say nothing of machining one out of a solid piece of aluminum bar stock. But clearly [Bob] is not most people. He recently dropped us a line about a video he uploaded to his aptly-named YouTube channel “Making Stuff”, where he goes through the steps required to turn raw materials into a writing instrument worthy of a Jedi.

Starting with a piece of aluminum …read more

The Miracle of Injection Molding: How Does it Work?

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Pretty much any household item nowadays has an involved, extremely well-thought-out manufacturing method to it, whether it’s a sheet of paper, an electrical outlet, a can of tuna, or even the house itself. Some of the stories of how these objects came to be are compelling, though, as one of the recent videos from [This Old Tony] shows as he takes a deep dive into a $5 ball valve, and uses it to talk about all of the cool things you can do with injection molding.

Injection molding is the process of casting molten plastic into more useful pieces of …read more

Hackaday Links: December 17, 2017

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Where do you go if you want crazy old electronic crap? If you’re thinking a ham swap meet is the best place, think again. [Fran] got the opportunity to clean out the storage closet for the physics department at the University of Pennsylvania. Oh, man is there some cool stuff here. This room was filled to the brim with old databooks and development boards, and a sample kit for the unobtanium Nimo tube.

The Gigatron is a Hackaday Prize entry to build a multi-Megahertz computer with a color display out of TTL logic. Now, all this work is finally paying …read more

An Mbed In Your Browser

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If you have dabbled in the world of ARM microcontrollers, you might be familiar with the Mbed platform, a software abstraction layer for a range of ARM-based small dev boards. If you don’t have an Mbed board but fancy giving it a go, you might imagine that you’d be out of luck, but [Jan Jongboom] could have an answer to your problem in the form of an Mbed simulation in your browser.

We’re not high-end ARM microcontroller developers here at Hackaday so beyond observing that it brings the Mbed abstraction layer binaries to the browser through the magic of Emscripten …read more

Cryptanalyse Your Air Con

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Infrared remote controls are simple and ubiquitous. Emulating them with the aid of a microcontroller is a common project that hackers use to control equipment as diverse as televisions, cable boxes, and home stereos. Some air conditioners can be a little more complicated, however, but [Ken]’s here to help.

The root of the problem is that the air conditioner remote was using a non-obvious checksum to verify if commands received were valid. To determine the function generating the checksum, [Ken] decided to bust out the tools of differential cryptanalysis. This involves carefully varying the input to a cryptographic function and …read more

Powering Your Mining Rig The Right Way

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It happens to the best of us. We power up our project and immediately run into issues. Be it spotty communication or microcontroller reset or any number of bugs that have us mystified and picking though our code… only to find that it’s a power supply issue. Anyone who has tried doing Raspberry Pi stuff and depended on the USB power from their PC has certainly been bit by this.

It’s the same with larger, more power hungry projects as well. [Nerd Ralph] has been running a mining rig for a few years now, and has learned just how important …read more

Final Project for Better Sleep

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It’s that time of year again, and students around the world are scrambling (or have already scrambled) to finish their final projects for the semester. And, while studying for finals prevents many from sleeping an adequate amount, [Julia] and [Nick] are seeking to maximize “what little sleep the [Electrical and Computer Engineering] major allows” them by using their final project to measure sleep quality.

To produce a metric for sleep quality, [Julia] and [Nick] set out to measure various sleep-related activities, specifically heart rate, motion and breath frequency. During the night, an Arduino Nano mounted to a glove collects data …read more

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