Day: June 11, 2020

Arduino Music Box Turns Stuffed Animal Into TV Personality

June 11, 2020 by 1 Comment

Childlike imagination is a wonderful thing. The ability to give life to inanimate objects and to pretend how they’re living their own life is precious, and not for nothing a successful story line in many movies. With the harsh facts or adulthood and reality coming for all of us eventually, it’s nice to see when some people never fully lose that as they get older. Even better when two find each other in life, like [er13k] and his girlfriend, who enjoy to joke about all the mischief their giant dog-shaped plush toy [Tobias] might secretly get into in their absence. The good thing about growing up on the other hand is the advanced technical opportunities at one’s disposal, which gave the imagined personality an actual face, and have it live inside an old CRT screen.

The initial idea was to just build a little music box as a gift, which beeps out [er13k]’s girlfriend’s favorite song with an Arduino on a speaker he salvaged from an old radio. But as things tend to go when you’re on a roll, he decided to make the gift even more personal. The result is still that music box, built in a 3D-printed case with a little piano that lights up the notes it plays, but in addition the Arduino now also displays a cartoon version of [Tobias] through composite video on an old TV. You can see for yourself in the video after the break how he goes through the day gifting flowers and drawings, and ponders about work and alternative career plans — adult problems are clearly universal.

Sure, the music box sound is a bit one-dimensional, but it’s nevertheless a highly thoughtful gift idea that triumphs with a peak personalization factor. If [er13k] ever wants to change the sound though, maybe there’s some inspiration in this drum machine we’ve seen just a few weeks ago, or this pocket sampler.

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Solder To Aluminum

June 11, 2020 by 95 Comments

If you’ve ever tried to solder to aluminum, you know it isn’t easy without some kind of special technique. [SimpleTronic] recently showed a method that chemically plates copper onto aluminum and allows you to solder easily. We aren’t chemists, so we aren’t sure if this is the best way or not, but the chemicals include salt, copper sulfate (found in pool stores), ferric chloride as you’d use for etching PCBs, and water.

Once you have bare aluminum, you prepare a solution from the copper sulfate and just a little bit of ferric chloride. Using salt with that solution apparently removes oxidation from the aluminum. Then using the same solution without the salt puts a copper coating on the metal that you can use for soldering. You can see a video of the process below.

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Learning About VNAs

June 11, 2020 by 5 Comments

We live in a good time to be an electronics geek. It used to be only the richest or shrewdest among us had a really good oscilloscope, while these days it is entirely feasible to have a scope that would have cost a fortune a few decades ago, a logic analyzer, arbitrary waveform generator, and what would have once been a supercomputer and still not be in debt. One of the cooler pieces of gear for people working on RF electronics is a vector network analyzer (VNA) which used to be exotic, but now can be bought for very little. But what do you do with it? [W2AEW] has the answer.

We always look forward to a video from [W2AEW]. Even if we know about the subject he covers, we usually pick up something new or interesting. Like all of his videos, this one is intensely practical. Not a lot of drawing but plenty of scope shots and experimenting.

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A Robotic Golf Club To (Possibly) Boost Your Game

June 11, 2020 by 8 Comments

Golf can be incredibly frustrating even for the well practiced player, and probably one of the leading causes for swearing on Saturday mornings. In effort to solve this global problem [Shane Wighton], is creating the ultimate cheat device robotic golf club, that can eliminate all the clubs in one, and adjust for the desired distance mid-swing.

Different golf clubs are mostly defined by their loft angle, or the angle at which the club face is designed to strike the ball in relation to the ground, with the purpose of changing the takeoff angle and therefor the distance traveled. To eliminate the need for different clubs, [Shane] made a head for which the loft angle can be set using a rotary encoder and display on the shaft. However building a tilting a mechanism that can survive the ±4000 lbs of force generated during impact requires some clever engineering. The first iteration was a rather impressive hydraulic design, but it required a large hydraulic power source and the pressure waves generated in the system caused the pistons in the head to blow out every time. The second iteration uses a hobby servo with a combination of machined and SLA printed parts, but in such a way that no force is transmitted to the servo at impact, similar to how a lead screw works. [Shane] actually managed to play a full 18 holes with no problems.

The second feature on the club is to adjust the loft angle mid-swing for the speed of the club to hit the ball a specified distance. A high precision IMU is used to measure the speed and angle of the club. The servo can’t move instantaneously, so it has to predict the impact velocity based on past data. Unfortunately no two swings are ever exactly the same, which introduces some error into the system. Continue reading “A Robotic Golf Club To (Possibly) Boost Your Game” →

Retrotechtacular: Wire Splicing The Army Way

June 11, 2020 by 31 Comments

For those of us who started experimenting with electricity when we were very young, one of the essential first skills was learning how to twist wires together. It seems like there’s not much to learn, but after a few failed attempts with nothing but your fingers, you learned a few tricks that are probably still with you to this day. It’s not surprising, then, that there’s an official US Army way to twist wires together, as this Signal Corps training film from 1941 shows.

Considering that the Signal Corps had nearly 80 years of experience with wiring battlefield communications at the outbreak of World War II, their methods were pretty solid, as were their materials. The film mainly concerns the splicing together of rolls of type W110-B field wire, used by the Signal Corps to connect command posts to forward positions, observation posts, and the rear echelons. More often than not laid directly upon the ground, the wire had to be tough, waterproof, and conductive enough that field telephone gear would still work over long loop lengths. As such, the steel-reinforced, rubber-and-fabric clad cable was not the easiest stuff to splice. Where we might cringe at the stresses introduced by literally tying a conductor in knots, it was all part of the job for the wire-laying teams that did the job as quickly as possible, often while taking enemy fire.

The film also has a section on splicing a new line into an existing, in-service circuit, using a T-splice and paying careful attention to the topology of the knots used, lest they come undone under stress. It’s fascinating how much thought was put into something as mundane as twisting wires, but given the stakes, we can appreciate the attention to detail.

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A Beginner’s Guide To Lithium Rechargeable Batteries

June 11, 2020 by 42 Comments

Batteries were once heavy, awkward things, delivering only a limp amount of current for their size and weight. Thankfully, over time, technology has improved, and in 2020, we’re blessed with capable, high-power lithium polymer batteries that can provide all the power your mobile project could possibly need. There are some considerations one must make in their use however, so read on for a primer on how to properly use LiPos in your project!

So Many Types!

With the first commercial lithium-ion battery entering the market in 1991, the (nearly) 30 years since have seen rapid development. This has led to a proliferation of different technologies and types of battery, depending on construction and materials used. In order to treat your batteries properly, it’s important to know what you’ve got, so paying attention to this is critical. Continue reading “A Beginner’s Guide To Lithium Rechargeable Batteries” →

Knitting Machine Rebuild Takes It To The Next Level

June 11, 2020 by 6 Comments

Those of us who to textile work may own a sewing machine and even if we’re really into it and have the funds, an overlocker. But there’s another machine in that field that few of us will have, and that’s a knitting machine. These machines have a sliding carriage over a long array of needles, and even the cheaper ones are way more expensive than for example a pretty decent oscilloscope. [Irene Wolf] has a Passap E6000 computerised knitting machine that is by no means an inexpensive one, and she’s made significant improvement to it by giving it new brains, a new motor controller, and replacing the mechanical rear needle bed with a set of computerised ones from the front of another machine.

In her write-up she goes in depth into the arrangement of sensors and electromagnets that operate the machine. She started with a lot of inspiration from a project at Hackerspace Bamberg, but used all the available Passap sensors as inputs where they had used only one. She has two Arduino M0 boards handling the inputs and a Raspberry Pi with control and user interface, and has posted some videos of the system in action one of which we’ve placed below the break.

We probably wouldn’t have had the courage to fearlessly hack such a high-value machine, and we’re particularly impressed by the result. The write-up is particularly interesting not only for the work itself, but for the detailed insight it gives to the workings of these machines. The best news – she’s not finished and there will be more installments.

While you’re waiting for more, remember this is by no means the first hacked knitting machine we’ve brought you.

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