The magnetosphere is the region of space surrounding the earth in which the earth’s magnetic field has most influence, and unlike the tidy pattern of magnetic field surrounding a bar magnet that you might have seen with iron filings at school, it’s distorted by the constant buffeting of the solar wind. This means that a significant quantity of potential energy is stored in its compression, and it’s this energy that Electro-Harmonix have their eye on.
Like Fox Mulder: we want to believe. Unfortunately the trouble with such ideas is readily visible with a quick web search; they attract a significant number of what one might charitably call cranks, and there is no shortage of unsubstantiated claims surrounding conspiracy theories, silenced genus inventors, and their mystery devices. Weird and wonderful descriptions and cryptic circuit diagrams abound, so separating the wheat if there is any from the inevitable chaff becomes a challenge. We respect that the Electro-Harmonix team are professional engineers who we hope are unlikely to become caught up in the weirder part of the Internet, but we’ll reserve our judgement until they provide more technical details of what they propose.
Generally, using a gun to turn your lights off is dangerous and expensive, but for the [DuctTape Mechanic], it’s just how he does things. Video also after the break. To be fair, he uses a salvaged Nintendo Zapper, not a firearm, and replaces the guts with an RF transmitter. We are shocked that he chose a radio model instead of infrared seeing as how he is repurposing a light gun, but our scores in Duck Hunt suggest he made the right choice.
The transmitter comes from a keychain remote, so it all fits neatly inside the Zapper chassis. A couple of wires hijack the stock button and run to the stock trigger, so you keep that authentic feel. The receiver side is a bit trickier. When it senses a button press, it sends a pulse, as you would find in a garage door opener, but to keep a lamp on, there needs to be some latching and so there is an Arduino. The microcontroller keeps a tally and operates a 10 amp relay module, so it is mostly acting as the glue between hardware. All of the mains electrical components sit in a blue plastic box with a receptacle on the front.
A 3D printer is a wonderful invention, but it needs maintenance like every machine that runs for long hours. [Rob Ward] had a well-used Robox 3D printer that was in need of some repairs, but getting the necessary replacement parts shipped to Australia was cost-prohibitive. Rather than see a beloved printer be scrapped as e-waste, he decided to rebuild it using components that he could more easily source. Unfortunately the proprietary software and design of the Robox made this a bit difficult, so it was decided a brain transplant was the best path forward.
Step one was to deduce how the motors worked. A spare RAMPS 1.4 board and Arduino Mega2560 made short work of the limit switches and XYZ motors. This was largely accomplished by splicing into the PCBs themselves. The Bowden filament driver motor had a filament detector and an optical travel sensor that required a bit of extra tuning, but now the challenging task was next: extruding.
With a cheap CR10 hot end from an online auction house, [Rob] began modifying the filament feed to feed in a different direction than the Robox was designed for (the filament comes in at a 90-degree angle on the stock Robox). A fan was needed to cool the filament feed line. Initial results were mixed with lots of blockages and clogs in the filament. A better hot end and a machined aluminum bracket for a smoother path made more reliable prints.
The original bed heater was an excellent heater but it was a 240 VAC heater. Reluctant to having high voltages running through his hacked system, he switched them out for 12 VDC adhesive pads. A MOSFET and MOSFET buffer allowed the bed to reach a temperature workable for PLA. [Rob] upgraded to a GT2560 running Marlin 2.x.x.
With a reliable machine, [Rob] stepped back to admire his work. However, the conversion to the feed being perpendicular to the bed surface had reduced his overall build height. With some modeling in OpenSCAD and some clever use of a standard silicone sock, he had a solution that fed the wire into the back of the hot end, allowing to reclaim some of the build height.
It was a long twelves months of work but the write-up is a joy to read. He’s included STL and SCAD files for the replacement parts on the printer. If you’re interested in seeing more machines rebuilt, why not take a look at this knitting machine gifted with a new brain.
In the previous versions, researchers showed that they were able to steer the SAW (Samara Autorotating Wing) by actuating the trailing edge of the blade with a servo. It takes input from an onboard 3-axis magnetometer and GPS, and adjusts the control surface continuously depending on its orientation to make it fly in the chosen direction. The latest paper (PDF) focuses on the craft’s new ability to switch from autorotation to a rapid dive and back to autorotation. Named the dSAW (diving SAW), it can drop like a rock by changing the control surface angle to almost 90° the wing to stall it. It exits the dive by simply moving the control surface back to the normal autorotation position. The kinetic energy built up during the dive is converted to rotational energy very quickly, which slows its vertical velocity to almost zero for an instant before settling back into its normal glide.
We can certainly see this being useful where the dSAW needs to quickly lose altitude to avoid being pushed off-course by the wind. The video below demonstrates this by dropping three dSAWs from an RC airplane. On command, they spread out, each in its designated direction, and then repeatedly switch between dive and autorotation mode as they descend to the ground. The researchers envision this being used to scatter sensor units over a large area in a controlled fashion from a single aircraft. What would you do with this technology? Let us know below.Continue reading “Helicopter Seed Robot Can Also Drop Like A Rock”→
If you have ever read anything about the history of UNIX, you may remember that its early development was influenced by an older operating system. MULTICS was developed in the 1960s by MIT and General Electric as a commercial operating system, and had been the system which UNIX writers [Thompson] and [Ritchie] had used. It became a Honeywell product, and the source code for its final commercial version was eventually released to the public. Has it become a dusty relic of interest only to historians? Seemingly not, because a new version has been released. It’s intended for us on the dps8m Honeywell mainframe simulator rather than physical hardware, so perhaps while it’s not such a dusty relic it remains something only for the enthusiast.
We won’t pretend to be experts on the architectures of 1960s mainframe operating systems, but it’s interesting to read for a moment about what it was in MULTICS that caused UNIX to be written. For something described by [Ken Thompson] as “Close to unusable”, with a fresh release in its 52nd year it isn’t doing badly.
My wife was watching a crime drama, and one of the plot twists involved a witness’ hearing aid malfunctioning so that he could hear electromagnetic waves around him. It’s not so implausible, if you think about it. Many hearing aids have a t-coil, which is essentially an inductor that’s designed to couple with the speaker in a telephone. If that went haywire, maybe you could hear all the changing magnetic fields around you, and if you could escape the constant hum of the mains power line, it might even be interesting.
So of course, she turns to me and says “we need to make one!” It shouldn’t be hard at all — a big inductor and an amplifier should do the trick. In fact, it’ll probably be easy enough that it’ll make a good introduction-to-electronics project for my son. But there are also enough unknowns here that it’ll be interesting. How big a coil? How close? How sensitive? What about that mains frequency bit? Ferrite core or not?
None of this is rocket science, for sure, but it will probably be full of kludges, discoveries, and straight-up exploration. In short, the perfect weekend project. And in the end, it’ll expose something that’s normally invisible, and that’s where the fun lies.
This must be the same urge that drove Faraday and Marconi, Volta and Maxwell. There’s something amazing about directly sensing, seeing, hearing, and understanding some of the stuff that’s outside of our limited hearing and eyesight, and yet is all around us. I can write down the equations that describe it — I learned them in school after all — but there’s no substitute for poking around in your own home. Who knows, maybe in a few more weekends we’ll build ourselves an all-band receiver.
What’s your favorite super power?
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When it comes to legged robots, it’s easy to think that the complexity and machining costs would keep these creatures far away from becoming anyone’s garage hobby. But, through a series of clever design choices, [Damian Lickindorf] has found a way to beat the odds and give life to Stanley, a low-cost, dynamic quadruped with some serious kick!
As if building a working legged robot weren’t already a tricky task, [Damian] has made some classy design choices to keep the price low and reduce fabrication complexity without sacrificing performance. Keeping up with the latest trend in Quasi-Direct Drive legged robots that started with the MIT Mini Cheetah, [Damian] constructed a small transmission with a gear reduction under 1:9. This choice slightly reduces the amount of heat produced by operating the motor at low-speeds with high torque without sacrificing too much control bandwidth (think: “leg responsiveness”).
Unlike the Cheetah, though, which uses a planetary gearbox, [Damian] opts for a capstan drive, a cable-driven transmission that’s both backlash free and backdriveable: two must-haves for force-sensitive dynamic legged robots. For legs, he’s opting for 2d machined FR4 (think: circuit board material). And for motors, he’s chosen a set of brushless motors with a large gap radius and driven by Moteus Drivers. The result is high fidelity, dynamic build that’s a fraction of the cost of some of the creatures we’re seeing emerge from academic research labs.
If you’re looking to feast your eyes on some action shots, look no further than [Damian’s] YouTube and Instagram presence. And if you’re looking to follow the project, have a look at the Hackaday.io project. While we’re eager to see the project continue to unfold, we’re thrilled by how far it’s come. In the meantime, be sure to take a look at one of the project’s inspirations: the Mjbots Quad A0.
Finally, since we’ve not seen capstan drives much on Hackaday, if you’re curious about these mechanisms and can get past the paywall, these two research papers might be a good place to dig deeper.