Primer On Servos Hits All The Basics

Servos are pretty basic fare for the seasoned hacker. But everyone has to start somewhere, and there’s sure to be someone who’ll benefit from this primer on servo internals. Who knows – maybe even the old hands will pick up something from a fresh perspective.

[GreatScott!] has been building a comprehensive library of basic electronics videos over the last few years that covers everything from using a multimeter to programming an Arduino. The last two installments delve into the electromechanical realm with a treatment of stepper motors along with the servo video below. He covers the essentials of the modern RC-type servo in a clear and engaging style that makes it easy for the newbie to understand how a PWM signal can translate into positional changes over a 180° sweep. He shows how to control a servo directly with an Arduino, with bonus points for including a simple 555-based controller circuit too. A quick look at the mods needed to convert any servo to continuous rotation wraps up the video.

If [GreatScott!]’s video whets your appetite for more, be sure to check out [Richard Baguley]’s deeper dive into servos. And when you’re ready to put your new-found knowledge into practice, maybe a nice project would be to convert a hobby servo into a linear actuator.

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A Virtual Glimpse Into The Forest

Taking a stroll through the woods in the midst of autumn is a stunning visual experience. It does, however, require one to live nearby a forest. If you are one of those who does not, [Koen Hufkens] has recently launched the Virtual Forest project — a VR experience  that takes you though a day in a deciduous forest.

First off, you don’t need a VR apparatus to view the scenery. Web-browsers and most smart phones are capable of displaying the 360 degree images. The Raspberry Pi 2-controlled Ricoh Theta S camera is enclosed in a glass lamp cover and — with the help of some PVC pipe — mounted on a standard fence post. Power is delivered ingeniously via a Cat5e cable, and a surge protector has also been included in case of lightning strikes.  Depending on when you view the website, you could be confronted with a black screen, or a kaleidoscope of color.

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Vintage Radio Transformed Into Custom PC Case

We see a lot of old radio restoration projects around here, and we have to admit to having mixed emotions about some of them. It seems a shame to go through the effort to lovingly restore a vintage Art Deco case only to stuff it with a Raspberry Pi and Bluetooth. Seems like if you’re going to restore a radio, go all the way and bring the original electronics back to life. But this radio “restoration” avoids that issue altogether by cleverly concealing a full PC build in a vintage radio case.

u3nwbpdClearly a labor of love, [SolomonZaraa]’s two-year effort guts the radio but still manages to pay homage to the original beauty of the 1939 vintage Philco 39-80 “tombstone” portable AM radio. The first design decision was to retask the original tuning dial as an analog thermometer using an Arduino and a servo. Then a new back was added with an extension for the motherboard and PSU, a drive cage was added, and a surprise slot for the DVD drive was built into the speaker grille. Nice brass trim and a good refinishing of the case resulted in an impressive and unexpected presentation.

You don’t have to go far in the Hackaday Wayback machine to find an antique radio with updated audio, but we’re pretty sure this is the first antique radio PC case mod we’ve seen. Nicely done, [Solomon]!

[via r/DIY]

Easy UFO Lights On Your Drone For Halloween

Sometimes it’s not so much what you put together, it’s how you use it. The folks at Adafruit have put up a project on how to dress up your drone with ‘UFO lights’ just in time for Halloween. The project is a ring of RGB LEDs and a small microcontroller to give any quadcopter a spinning ‘tractor beam light’ effect. A 3D printed fixture handles attachment. If you’re using a DJI Phantom 4 like they are, you can power everything directly from the drone using a short USB cable, which means hardly any wiring work at all, and no permanent changes of any kind to the aircraft. Otherwise, you’re on your own for providing power but that’s probably well within the capabilities of anyone who messes with add-ons to hobby aircraft.

One thing this project demonstrates is how far things have come with regards to accessibility of parts and tools. A 3D printed fixture, an off-the-shelf RGB LED ring, and a drop-in software library for a small microcontroller makes this an afternoon project. The video (embedded below) also demonstrates how some unfamiliar lights and some darkness goes a long way toward turning the otherwise familiar Phantom quadcopter into a literal Unidentified Flying Object.

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Build The Simplest Bipolar Power Supply

How many integrated circuits do you need to build up a power supply that’ll convert mains AC into a stable DC voltage? Would you believe, none? We just watched this video by [The Current Source] (embedded below), where he builds exactly that. If you’re in the mood for a very well done review of diode bridges as well as half- and full-wave rectifiers, you should check it out.

First off, [TCS] goes through the basics of rectification, and demonstrates very nicely on the oscilloscope how increasing capacitance on the output smooths out the ripple. (Hint: more is better.) And then it’s off to build. The end result is a very simple unregulated power supply — just a diode bridge with some capacitors on the output — but by using really big capacitors he gets down into the few-millivolt range for ripple into a constant load.

The output voltage of this circuit will depend on the average current drawn, but for basically static loads this circuit should work well enough, and the simplicity of just tossing gigantic capacitors at the problem is alluring. (We would toss in a linear regulator somewhere.)

Quibbling over circuit designs isn’t why you’re watching this video, though. It’s because you want to learn something. Check out the rest of his videos as well. [TCS] has only been at it a little while, but it looks like this is going to be a channel to watch.

https://www.youtube.com/watch?v=0iDCsrMM7M0

Living Off The Grid, On Water Power

When you think of living off the grid, you often think of solar power. But if you’ve got a good head, and enough flow, water power can provide a much more consistent flow of electrons. All it requires is a little bit of engineering, epic amounts of manual labor, and some tricks of the trade, and you’ll have your own miniature hydroelectric power plant.

[Homo Ludens], the playful ape, has what looks like a fantastic self-sufficient home/cabin in a beautiful part of Chile. His webpages are a tremendous diary of DIY, but the microhydro plant stands out.

You might expect that building a hydro plant involves a lot of piping, and trenching to lie that pipe in, but the exact extent, documented in many photos, is sobering. At places, the pipe needed to be bent, and [Homo Ludens] built a wire-mesh pipe heater to facilitate the work — with the help of a few friends to weigh the pipe down at either end and create the bend. The self-wound power transformer is also a beauty.

There’s a lot more detail here than we can possibly get into, so go check it out. And if you’re in the mood for more hydro, we’ve recently run a writeup of a less ambitious, but still tidy, project that you should see. Or you could just rip apart an old washing machine.

Thanks [Patrick] for the great tip!

Diamonds Are For Data Storage

Most data storage devices we currently use are, at their core, two-dimensional. Sure, a hard drive might have multiple platters, but the data storage takes place on a flat surface. Even an optical drive is effectively a single surface that holds data. At the  City College of New York, they are experimenting with storing data in three dimensions using lab-grown diamonds and LASERs.

Usually, diamonds that have few flaws are more valuable. But in this application, the researchers exploit the flaws to store information. Optical memory that uses a volume instead of a surface isn’t exactly new. However, it is difficult to use these techniques in a way that is rewritable.

Diamonds are a crystalline structure of carbon atoms. Sometimes, though, a carbon atom is missing from the structure. That’s a vacancy. Another defect is when a nitrogen atom replaces a carbon atom. Sometimes a vacancy occurs next to a rogue nitrogen atom and that causes an NV (nitrogen vacancy) center.

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