A Two-Range OLED Capacitance Meter

May 12, 2018 by 14 Comments

If you are just starting out in electronics, you need tools. But it is hard to build all your tools. Even though we see a lot of soldering station builds, you really ought to have a soldering iron to build the station. It is hard to troubleshoot a multimeter you just built if you don’t have a multimeter. However, a capacitance meter is a handy piece of gear, relatively simple to build, and you should be able to get it working without an existing capacitance meter. [gavinlyonsrepo] presents a simple design using an Arduino, an OLED display, and a few components.

The principle of operation is classic. On one range, the Arduino charges the capacitor through one resistor and discharges it through another while timing the operation. The amount of time taken corresponds to the capacitance.

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The Current Advances Of PCB Motors

May 12, 2018 by 9 Comments

There’s something to be said about the falling costs of printed circuit boards over the last decade. It’s opened up the world of PCB art, yes, but it’s also allowed for some experimentation with laying down fine copper wires inside a laminate of fiberglass and epoxy. We can design our own capacitive touch sensors. If you’re really clever, you can put coils inside four-layer PCBs. If you’re exceptionally clever, you can add a few magnets and build a brushless motor out of a PCB.

We first saw [Carl]’s PCB motor at the beginning of the year, but since then we’ve started the Hackaday Prize, [Carl] entered this project in the Prize, and this project already made it to the final round. It’s really that awesome. Since the last update, [Carl] has been working on improving the efficiency and cost of this tiny PCB motor. Part of this comes from new magnets. Instead of a quartet of round magnets, [Carl] found some magnets that divide the rotor into four equal pieces. This gives the rotor a more uniform magnetic field across its entire area, and hopefully more power.

The first version of this 3D printed PCB motor used press-fit bushings and a metallic shaft. While this worked, an extra piece of metal will just drive up the cost of the completed motor. [Carl] has redesigned the shaft of the rotor to get rid of the metallic axle and replace it with a cleverly designed, 3D printed axle. That’s some very nice 3D printing going on here, and something that will make this motor very, very cheap.

Right now, [Carl] has a motor that can be made at any board house that can do four-layer PCBs, and he’s got a rotor that can be easily made with injection molding. The next step is closed-loop control of this motor. This is a challenge because the back-EMF generated by four layers of windings is a little weak. This could also be accomplished with a hall sensor, but for now, [Carl] has a working PCB motor. There’s really only one thing to do now — get the power output up so we can have real quadcopter badges without mucking around with tiny brushed motors.

[Carl] has put up a few videos describing how his PCB motor works; you can check those out below.
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A Vacuum Tube And Barbecue Lighter X-Ray Generator

May 12, 2018 by 58 Comments

A certain subset of readers will remember a time when common knowledge held that sitting too close to the TV put you in mortal peril. We were warned to stay at least six feet back to avoid the X-rays supposedly pouring forth from the screen. Nobody but our moms believed it, so there we sat, transfixed and mere inches from the Radiation King, working on our tans as we caught up on the latest cartoons. We all grew up mostly OK, so it must have been a hoax.

Or was it? It turns out that getting X-rays from vacuum tubes is possible, at least if this barbecue lighter turned X-ray machine is legit. [GH] built it after playing with some 6J1 rectifier tubes and a 20-kV power supply yanked from an old TV, specifically to generate X-rays. It turned out that applying current between the filament and the plate made a Geiger counter click, so to simplify the build, the big power supply was replaced with the piezoelectric guts from a lighter. That worked too, but not for long — the tube was acting as a capacitor, storing up charge each time the trigger on the lighter was pulled, eventually discharging through and destroying the crystal. A high-voltage diode from a microwave oven in series with the crystal as a snubber fixed the problem, and now X-rays are as easy as lighting a grill.

We have to say we’re a wee bit skeptical here, and would love to see a video of a test. But the principle is sound, and if it works it’d be a great way to test all those homebrew Geiger counters we’ve featured, like this tiny battery-powered one, or this one based on the venerable 555 timer chip.

Jeremy Cook's strandbeest kit RC conversion

Stepper Motor And Key Fob Controlled Strandbeest

May 12, 2018 by 7 Comments

We never tire of watching Strandbeests with their multitude of legs walking around, and especially enjoy the RC ones. [Jeremy Cook], prolific Strandbeest maker, just made one by motorizing and adding remote control to a small, plastic wind-powered kit.

We’ve seen a Strandbeest kit conversion like this before, such as this DC motor one but it’s always interesting to see how it can be done differently. In [Jeremy’s], he’s gone with two inexpensive $2.00 stepper motors. The RC is done using a keyfob transmitter with a receiver board wired into an Arduino Nano’s analog pins. He tried driving it directly off the LiPo batteries but had issues which he solved by adding a 5-volt regulator. Check out his build and the modified Strandbeest walking around in the video below.

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NeoPixel Game Rewards Button Mashing

May 12, 2018 by 2 Comments

Who has the fastest thumbs at Maker Faire UK? That’s the question [wellsey1972] sought to answer when he created this simple game using little more than two NeoPixel rings, two chunky arcade buttons, and a Trinket.

The idea is simple: each button push lights up one NeoPixel. The first one to fill up their ring is the winner, and is treated to a ring of flashing green lights. The loser, of course, gets flashing red. Both controllers are hard-wired to a box containing a Trinket, a custom PCB with pull-up resistors, and two sets of solderless terminals. [wellsey1972] smartly re-purposed a cat 5 cable for sleeker wiring.

He has a few ideas for the future, like going wireless, printing smaller controllers, and making winning more difficult via potentiometer. We humbly suggest that the loser be taunted by the cry of a sad tuba. Mash past the break for a brief demo.

If you like lights and simplicity but find this build less than challenging, try building a minimal secret maze game.

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Pimp My Scope

May 12, 2018 by 5 Comments

Most of us have heard some form of the adage, “You can buy cheaper, but you’ll never pay less.” It means that cheaper products ultimately do not stand up to the needs of their superior counterparts. Hackers love to prove this aphorism wrong by applying inexpensive upgrades to inexpensive tools to fill up a feature-rich tool bag. Take [The Thought Emporium] who has upgraded an entry-level microscope into one capable of polarized and dark-field microscopy. You can also see the video after the break.

Functionally, polarized images can reveal hidden features of things like striations in crystals or stress lines in hot glue threads. Dark-field microscopy is like replacing the normally glaring white background with a black background, and we here at Hackaday approve of that décor choice. Polarizing filters sheets are not expensive and installation can be quick, depending on your scope. Adding a dark-field filter could cost as much as a dime.

Like most mods, the greatest investment will be your time. That investment will pay back immediately by familiarizing you with your tools and their workings. In the long-run, you will have a tool with greater power.

Simple mods like the light source can be valuable, but upgrades are not limited to optical scopes, an electron microscope was brought back to life with Arduino

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Save The Tally Ho: Rebuilding A Historic Yacht

May 11, 2018 by 15 Comments

[Leo Sampson Goolden] is a boatbuilder and Sailor. He’s a prime example of a dwindling group of shipwrights who build sailing vessels the traditional way. In 2017, he was given the opportunity to buy Tally Ho, a Yacht built back in 1910. Once a proud ship, Tally Ho now sat as a shell under a shrink-wrap tarp. Her deck was rotted, her keel cracked. Any sane person would have moved on. Thankfully [Leo] is not quite sane, and began a quest to bring this history ship back to its former glory.

Tally Ho isn’t just an old boat. She is a 48-foot long gaff cutter yacht designed by the famous Albert Strange and built in Sussex, England. Tally Ho won the 1927 Fastnet Race (corrected time) when rough seas caused all but two boats to bow out.

To say [Leo] has his work cut out for him would be an understatement. Tally Ho lived a hard life, from racing to fishing. A complete restoration was needed. In fact, it would have been cheaper and easier to build a replica rather than restore the original. [Leo] wanted to save Tally Ho though, so he bought the boat for one dollar, and began to put all his time, effort, and funds into restoring her. This work includes carefully documenting each piece as it is removed.

Some of the tools and materials are traditional – such as chisels and red lead putty. But [Leo] is using power tools as well, including a custom-built chainsaw mount for shaping the keel. His videos are entertaining and illustrate many techniques of boat building. Wherever possible, [Leo] adds captions to explain the meanings of boat building terms, as well as explains the different terms used in England and the USA. In the latest video, you can watch along as [Leo] creates a Dutchman to fill in a knot in the keel. Can check that out in the video after the break.

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