Day: March 14, 2019

[Ben Krasnow] Drills Really Small Holes With Electricity

March 14, 2019 by 21 Comments

Drilling holes is easy; humans have been doing it in one form or another for almost 40,000 years. Drilling really tiny holes in hard materials is more challenging, but still doable. Drilling deep, straight holes in hard materials is another thing altogether.

Luckily, these days we have electric discharge machining (EDM), a technique that opens up all kinds of possibilities. And just as luckily, [Ben Krasnow] got his hands on some EDM gear to try out, with fascinating results. As [Ben] explains, at its heart EDM is just the use of a small arc to ablate metal from a surface. The arc is precisely controlled, both its frequency via an arc controller, and its location using CNC motion control. The arc controller has always been the sticking point for home EDM, but the one [Ben] tried out, a BaxEDM BX17, is squarely aimed at the small shop market. The whole test platform that [Ben] built has a decidedly home-brew look to it, with a CNC gantry rigged up to a water tank, an EDM drill head spinning the drill rods slowly, and an airless paint gun providing high-pressure process fluid. The video below shows that it works remarkably well nonetheless.

While we’re certainly keen to see [Ben]’s promised videos on EDM milling and cutting, we doubt we’ll line up to shell out €2,950 for the arc controller he used. If you have more courage than money, this mains-powered EDM might be a better fit.

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MCAS And The 737: When Small Changes Have Huge Consequences

March 14, 2019 by 164 Comments

When the first 737 MAX entered service in May of 2017, it was considered a major milestone for Boeing. For nearly a decade, the aerospace giant had been working on a more fuel efficient iteration of the classic 737 that first took to the skies in 1967. Powered by cutting-edge CFM International LEAP engines, and sporting modern aerodynamic improvements such as unique split wingtips, Boeing built the new 737 to have an operating cost that was competitive with the latest designs from Airbus. With over 5,000 orders placed between the different 737 MAX variants, the aircraft was an instant success.

But now, in response to a pair of accidents which claimed 346 lives, the entire Boeing 737 MAX global fleet is grounded. While the investigations into these tragedies are still ongoing, the preliminary findings are too similar to ignore. In both cases, it appears the aircraft put itself into a dive despite the efforts of the crew to maintain altitude. While the Federal Aviation Administration initially hesitated to suspend operations of the Boeing 737 MAX, they eventually agreed with government regulatory bodies all over the world to call for a temporary ban on operating the planes until the cause of these accidents can be identified and resolved.

For their part, Boeing maintains their aircraft is safe. They say that grounding the fleet was done out of an “abundance of caution”, rather than in direct response to a particular deficiency of the aircraft:

Boeing continues to have full confidence in the safety of the 737 MAX.  However, after consultation with the U.S. Federal Aviation Administration (FAA), the U.S. National Transportation Safety Board (NTSB), and aviation authorities and its customers around the world, Boeing has determined — out of an abundance of caution and in order to reassure the flying public of the aircraft’s safety — to recommend to the FAA the temporary suspension of operations of the entire global fleet of 371 737 MAX aircraft.

Until both accident investigations are completed, nobody can say with complete certainty what caused the loss of the aircraft and their passengers. But with the available information about what changes were made during the 737 redesign, along with Boeing’s own recommendations to operators, industry insiders have started to point towards a fault in the plane’s new Maneuvering Characteristics Augmentation System (MCAS) as a likely culprit in both accidents.

Despite the billions of dollars spent developing these incredibly complex aircraft, and the exceptionally stringent standards their operation is held to, there’s now a strong indication that the Boeing 737 MAX could be plagued with two common issues that we’ve likely all experienced in the past: a software glitch and poor documentation.

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NES On RISC-V

March 14, 2019 by 19 Comments

RISC architecture might change the world, but it runs an NES emulator right now. That’s thanks to MaixPy, the new MicroPython for the K210, the recently released RISC-V microcontroller that’s making waves in the community. [Robot Zero One] has the tutorial and [Other Dave] of EEVBlog has a video of the thing in action.

The Sipeed K210 came to the English-speaking world in the form of a weird pre-order thing on Taobao last October promising a dual-core RISC-V CPU for just a few bucks. Seeed, the same people who brought the ESP8266 into mass distribution quickly latched on and started selling modules last February. Now, Seeed is looking at a Raspberry Pi hat using a Sipeed module, and the future for RISC-V microcontrollers is looking great. Now someone just needs to write some software. That’s exactly what the engineers at Sipeed did, and somewhere in one of the released binaries there’s an NES emulator.

The parallel to the question of if something can run Doom is if something can run an NES emulator, so with the release of MicroPython support for the K210, the obvious thing to do is to release an NES emulator. The hardware required is a Maix M1w Dock, available from Seeed and Banggood.

The new support for MicroPython is great, and an NES emulator is amazing, but this should really come as no surprise. From our first hands on with the first Open Source microcontroller two years ago, RISC-V was obviously faster. Now it’s cheap, and we can’t wait to see what’ll come next.

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Simple Sensor Provides Detailed Motion Capture For VR Hands

March 14, 2019 by 7 Comments

Consider the complexity of the appendages sitting at the end of your arms. The human hands contain over a quarter of the entire complement of bones in the body, use dozens of muscles both in the hand itself and extending up the forearm, and are capable of almost infinite variance in the movements they can create. They are exquisite machines.

And yet when it comes to virtual reality, most simulations treat the hands like inert blobs. That may be partly due to their complexity; doing motion capture from so many joints can be computationally challenging. But this pressure-sensitive hand motion capture rig aims to change that. The product of an undergraduate project by [Leslie], [Hunter], and [Matthew], the idea was to provide an economical and effective way to capture gestures for virtual reality simulators, which generally focus on capturing large motions from the whole body.

The sensor consists of a sandwich of polyurethane foam with strain gauge sensors embedded within. The user slips his or her hand into the foam and rests the fingers on the sensors. A Teensy and twenty lines of code translate finger motions within the sandwich into five axes of joystick movement, which is then sent to Unreal Engine, where finger motions were translated to a 3D-model of a hand to play a VR game of “Rock, Paper, Scissors.”

[Leslie] and her colleagues have a way to go on this; testers complained that the flat hand posture was unnatural, and that the foam heated things up quickly. Maybe something more along the lines of these gesture-capturing gloves would work?