Pumping Up An Antenna From A Stream Of Sea Water

Our Hackaday readership represent a huge breadth of engineering experience and knowledge, and we get a significant number of our story tips from you. For instance, today we are indebted to [sonofthunderboanerges] for delivering us a tip in the comment stream of one of our posts, detailing an antenna created by coupling RF into a jet of sea water created with a pump. It’s a few years old so we’re presenting it as an object of interest rather than as a news story, but it remains a no less fascinating project for that.

The antenna relies on the conductivity of sea water to view a jet of water as simply another conductor to which RF can be coupled. The jet is simply adjusted by altering the flow rate until it is a quarter wavelength long at the desired frequency, at which point it is a good analogue of a metal whip antenna. The RF is coupled at the base by a ferrite cored transformer that clips around the nozzle ejecting the water, and a bandwidth from 2MHz to 400MHz is claimed. If you work with RF you will probably wince at the sight of salt water coming near the RF connector, as we did.

The advantage of the system is that it allows antennas of multiple frequencies to be created at very short notice and using very little space or weight when not in use. The creator of the antenna at the US Navy’s SPAWAR technology organization points to its obvious application on Navy warships. Whether or not the sailors are using these antennas now isn’t clear, but one thing’s for certain, the idea hasn’t gone away. Early last year Popular Mechanics reported on a similar project under way courtesy of Mitsubishi, in Japan.

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Engineer’s Primer on DIY Christmas Light Shows

Each year brings new Christmas light shows, with synchronised music and wild blinking decorations to light your eyeballs ablaze. Now, many of us have dabbled in the dark arts of blinken, tinkering with LEDs or flashing a neon bulb or two. There’s plenty of tutorials on how to control all manner of lights, but they’re often written for novices. Learning the basics of electronics for the nth time when you just need to know the specifics of a protocol or what IC you need can be a total drag. That’s why [Bill Porter] has written the Engineer’s Guide to DIY Computer Controlled Holiday Lights.

[Bill] covers the topic from start to finish – not just the technical side of things, but practical considerations about where to source components, and timescales for keeping your project on track. It’s no coincidence this is coming out in January – if you want to get something big up and running for Christmas, it’s time to start now! The guide gives links to forum communities that put in large group orders for parts early, and ship them slow to save money.

Other areas covered include software for creating advanced sequences for your lighting setup, which allow you to map animations over your entire layout. There’s also tips on which controller hardware to use for incandescent lights and the now-ubiquitous WS2811 strings. Even better, [Bill] shares specific tips on how to avoid common problems like voltage drop over long pixel runs and communication issues.

It’s a testament to [Bill] and his experience – the guide is an excellent way to get right up to speed with the state of the art in DIY Christmas light shows, and will save you from all manner of pitfalls. If you need to build something big this year and don’t want to reinvent the wheel, this is for you.

It’s not the first time we’ve heard from [Bill] either – check out his stunning wedding invitations or his repair of a science museum exhibit.

IoT-ify All Things: LG Has Gone Overboard

If you been following Hackaday lately, you’ve surely noticed an increased number of articles about IoT-ifying stuff. It’s a cool project to take something old (or new) and improve its connectivity, usually via WiFi, making it part of the Internet of Things. Several easy to use modules, in particular the ESP8266, are making a huge contribution to this trend. It’s satisfactory to see our homes with an ESP8266 in every light switch and outlet or to control our old stereo with our iPhone. It gives us a warm fuzzy feeling. And that’s completely fine for one’s personal projects.

But what happens when this becomes mainstream? When literally all our appliances are ‘connected’ in the near future? The implications might be a lot harder to predict than expected. The near future, it seems, starts now.

This year, at CES, LG Electronics (LG) has introduced Smart InstaView™, a refrigerator that’s powered by webOS smart platform and integrated with Amazon’s Alexa Voice Service.

… with webOS, consumers can also explore a host of WiFi-enabled features directly on the refrigerator, creating a streamlined and powerful food management system all housed directly on the front of the fridge door. Amazon’s Alexa Voice Service gives users access to an intelligent personal assistant that, in addition to searching recipes, can play music, place Prime-eligible orders from Amazon.com…

This is ‘just’ a fridge. There are other WiFi-enabled appliances by now, so what?  Apparently, during the LG press conference last Wednesday, the company marketing VP David VanderWaal said that from 2017 on, all of LG’s home appliances will feature “advanced Wi-Fi connectivity”.

Notice the word advanced, we wonder what that means? Will ‘advanced’ mean complicated? Mesh? Secure? Intelligent? Will our toaster finally break the Internet and ruin it for everyone by the end of the year? Will the other big players in the home appliances market jump in the WiFi wagon? We bet the answer is yes.

Here be dragons.

[via Ars Technica]

Give Your Raspberry Pi A Good Hammering

One of the features of the Raspberry Pi Zero is that it arrives with no GPIO header pins installed. The missing pins reduce the price of the little computer, as well as its shipping volume. A task facing most new Pi Zero owners has therefore been to solder a set of pins into the holes, and indeed many suppliers will sell you the pins alongside your new Zero.

The British Pi accessories supplier Pimoroni think they may have a solution to this problem, with a set of solderless pins that the user is expected to fit by tapping both pins and Pi with a hammer. Each pin is designed to deform under pressure, and grip the through-plated walls of the hole in the PCB. In reality they are push-fit pins designed to be fitted with a press or a special tool, but since the average Zero buyer will have neither they supply a small laser-cut jig and give instructions to tap carefully with a pin hammer or similar. They have a demonstration as part of their regular Bilge Tank podcast, which we’ve included below the break.

Pins like these can be quite reliable when installed with the proper tools. They are often used in military and aerospace systems. In this case though, we expect that a chorus of you will be limbering up to comment that it would be far better to solder the connector, and we can’t help agreeing with you. Of course this product isn’t really marketed at Hackaday readers. Instead, the target market of a board like the Zero are children. For them soldering may well be a step too far. We can’t help wondering though whether hammer installation will deliver a reliable enough contact, and whether we’ll see a horde of youngsters whose Pi HATs don’t work due to dodgy connectors. Aside from the ones who’ve broken their Zeros with hammering that was a bit enthusiastic, that is.

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David Krum: The Revolution in Virtual Reality

[David Krum] is associate lab director at the Mixed Reality Lab at the Institute for Creative Technologies at USC. That puts him at the intersection of science and engineering: building cool virtual reality (VR) devices, and using science to figure out what works and what doesn’t. He’s been doing VR since 1998, so he’s seen many cool ideas come and go. His lab was at the center of the modern virtual reality explosion. Come watch his talk and see why!

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Anatomy Of A Digital Broadcast Radio System

What does a Hackaday writer do when a couple of days after Christmas she’s having a beer or two with a long-term friend from her university days who’s made a career in the technical side of digital broadcasting? Pick his brains about the transmission scheme and write it all down of course, for behind the consumer’s shiny digital radio lies a wealth of interesting technology to try to squeeze the most from the available resources.

In the UK, our digital broadcast radio uses a system called DAB, for Digital Audio Broadcasting. There are a variety of standards used around the world for digital radio, and it’s fair to say that DAB as one of the older ones is not necessarily the best in today’s marketplace. This aside there is still a lot to be learned from its transmission scheme, and from how some of its shortcomings were addressed in later standards. Continue reading “Anatomy Of A Digital Broadcast Radio System”