[David Schneider] asked himself, “How big a radio antenna would you need to observe anything interesting?” The answer turns out to be a $150 build of a half meter antenna. He uses it to detect the motions of the spiral arms of the Milky Way. The first attempt was a satellite TV dish and a cantenna feed, which didn’t work as the can wasn’t big enough to pick up signals at the 21cm wavelength of hydrogen emissions. Interstellar gas clouds are known to emit radio energy at this frequency.
Looking online, [David] tried aluminized foam board insulation, but was worried that the material didn’t seem to actually be conductive. A quick thrown-together Faraday cage with a cell phone didn’t seem to block any calls. Abandoning that approach, he settled on aluminum flashing used for roofing.
For many of us, the optical drive is a thing of the past. Once considered essential, the technology is no longer featured in the average laptop,where their omission saves plenty of precious space, and they’re rare on desktops, too. However, every now and then, something comes up and it’d be useful to have one on hand. [Klattimer] has just the solution for the MacOS set.
The Python Online Disk Server, or PYODS, is a tool that allows one to serve optical drives or ISO images over a network to MacOS clients. In its basic configuration, it shares all optical drives on a system, as well as all images found in a select folder. Thanks to using Python, it allows other operating systems to share their drives with Macs. It relies on Apple’s existing API to function, and should be a handy tool for anyone that regularly finds themselves having to scratch around for a way to mount an ISO in a pinch.
Thankfully, outside of legacy applications, cumbersome optical technologies and image files are a thing of the past. If you’ve got drives laying around that you’re not using anymore, why not repurpose them into a plotter?
Typically, amateur radio operators use the minimum power needed to accomplish a contact. That’s just part of being a good spectrum citizen, and well-earned bragging rights go to those who make transcontinental contacts on the power coming from a coin cell. But sometimes quantity has a quality all its own, and getting more power into the ether is what the contact requires. That’s where builds such as this well-engineered 600W broadband RF amplifier come into play.
We’re really impressed with the work that [Razvan] put into this power amp. One of the great joys of being a ham is being able to build your own gear, and to incorporate the latest technology long before the Big Three manufacturers start using it. While LDMOS transistors aren’t exactly new – laterally-diffused MOSFETs have been appearing in RF power applications for decades – the particular parts used for the amp, NXP’s MRF300 power transistors, are pretty new to the market. A pair of the LDMOS devices form the heart of the push-pull amp, as do an array of custom-wound toroids and transformers including a transmission line transformer wound with 17-ohm coax cable. [Razvan] paid a lot of attention to thermal engineering, too, with the LDMOS transistors living in cutouts in the custom PCB so they can mate with a hefty heatsink. Even the heatsink compound is special; rather than the typical silicone grease, he chose a liquid metal alloy called Gallinstan. The video below gives a tour of the amp and shows some tests with impressive results.
What can you do with ferromagnetic PLA? [TheMixedSignal] used it to give new meaning to the term ‘musicians’ gear’. He’s made a proof of concept for a DIY tone generator, which is the same revolutionary system that made the Hammond organ sing.
Whereas the Hammond has one tonewheel per note, this project uses an Arduino to drive a stepper at varying speeds to produce different notes. Like we said, it’s a proof of concept. [TheMixedSignal] is proving that tonewheels can be printed, pickups can be wound at home, and together they will produce audible frequencies. The principle is otherwise the same — the protruding teeth of the gear induce changes in the magnetic field of the pickup.
[TheMixedSignal] fully intends to expand on this project by adding more tone wheels, trying different gear profiles, and replacing the stepper with a brushless motor. We can’t wait to hear him play “Karn Evil 9”. In the meantime, put on those cans and check out the demo/build video after the break.
Bobble-Bot uses the standard inverted pendulum problem to teach modern robotic control using a Raspberry Pi, RT-Linux, and ROS.
We’re really impressed by the polish and design effort put into this project, and it’s no surprise that it’s a finalist in the 2019 Hackaday Prize. Bobble-Bot is a top heavy bot sitting on two BLDC motors. The brains of the operation is a Raspberry Pi running real-time Linux and ROS. This allows the robot to respond in a predictable manner to its inputs, and also allows for more control over thread priority than a regular kernel. In the past we’ve seen these inverted pendulum bots mostly being run on micro-controllers for just this reason, so it’s cool to see it make the jump to Linux.
Mechanically the bot can be printed on any consumer grade printer and assembled. We really appreciate the small details like making sure one screw size could be used to assemble the entire bot, eliminating the need for multiple tools.
They also have a simulator, and the bot’s software was built inside of that. It was a big moment when the real-world behavior finally matched the simulated performance. In fact, if you’re interested in the Bobble-Bot, you can try it out in simulation before committing to building the whole thing.
This project seems like a fun build for any hacker. We would have loved to have a project as polished and up-to-date as this one when we were learning controls in university. Video introducing it after the break.
Back at the 2017 Superconference, Hackaday Managing Editor Elliot Williams started his talk about the so-called “Internet of Things” by explaining the only part he doesn’t like about the idea is the Internet… and the things. It’s a statement that most of us would still agree with today. If anything, the situation has gotten worse in the intervening years. Commercial smart gadgets are now cheaper and more plentiful than they’ve ever been, but it seems like precious little has been done to improve their inherent privacy and security issues.
But his talk doesn’t serve to bash the companies producing these devices or even the services that ultimately folded and left their customers with neigh useless gadgets. That’s not his style. The central theme of “Nexus Technologies: Or How I Learned to Love WiFi”is that a smart home can be wonderful thing, assuming it works the way you want it to. Elliot argues that between low-cost modular hardware and open source software, the average hacker has everything they need to build their own self-contained home automation ecosystem. One that’s not only cheaper than what they’re selling at the Big Box electronics store, but also doesn’t invite any of the corporate giants to the party.
Of course, it wasn’t always so. A decade ago it would have been all but impossible, and five years ago it would have been too expensive to be practical. As Elliot details his journey towards a truly personal smart home, he explains the advances in hardware and software that have made it not just possible on the DIY level, but approachable. The real takeaway is that once more people realize how cheap and easy it is to roll your own smart home gadgets, they may end up more than willing to kick Big Brother to the curb and do IoT on their own terms.
This previously unpublished recording somehow slipped between the cracks of the editing room floor but upon recent discovery, it’s still just as relevant today. Take a look at Elliot’s view on Nexus Technologies, then join us after the break for a deeper dive. Make sure to subscribe to Hackaday’s YouTube channel to get in on the 2019 Hackaday Superconference live stream starting Saturday, November 16th.
Chances are pretty good that you’ve got a box or a bin somewhere in your shop with coils of SMD component tapes in it. If you’re lucky, the coils are somewhat contained in their conductive Mylar bags; if you’re more like us, the tapes are flopping around loose in an attempt to seemingly tie themselves together. In either case, these 3D-printed SMD magazines will bring a little order to the chaos, and make board assembly a little bit easier.
When we saw [Robin Reiter]’s build, we thought these would be cassettes for some sort of pick-and-place machine. But while they certainly look like they could be adapted to an automated PnP setup, [Robin]’s main goal was to provide organized storage for loose tapes. Each magazine has a circular reservoir to hold the coiled tape, with an exit slot at the front and a wedge that directs the cover tape in the opposite direction. This removes the cover tape to expose the components, clears it away from the pickup area, and as a bonus, allows the component tape to be advanced just by pulling back on the cover. Each magazine has a spring-loaded latch that clips onto a base that looks a bit like a DIN-rail; the weighted base holds several magazines and makes it easy to set up a manual pick-and-place session. The video below shows all the details.
For certain personality types, this really scratches an itch. We love the modular design, and the organization that these would bring to our shop would really help clean things up a bit. And if [Robin] were ever to take this design to the next level, adding something like this could be useful.
