Local Simulation Feature To Be Removed From All Autodesk Fusion 360 Versions

August 12, 2022 by Maya Posch 166 Comments

The removal of features from Autodesk products would appear to be turning into something of a routine at this point, with the announced removal of local simulations the latest in this series. Previously Autodesk had severely cut down the features available with a Personal Use license, but these latest changes (effective September 6) affect even paying customers, no matter which tier.

While previously executed local simulations on designs will remain accessible, any updates to these simulations, as well as any new simulations will have to use Autodesk’s cloud-based solver. This includes the linear stress, modal frequencies, thermal, and thermal stress simulation types, with each type of simulation study costing a number of Cloud Tokens.

Solving a linear simulation should initially cost 0 tokens, but the other types between 3 – 6 tokens, with the exact cost per token likely to vary per region. This means that instead of solving simulations for free on one’s own hardware, the only option in a matter of weeks will be solely through Autodesk’s cloud-based offerings.

Naturally, we can see this change going over exceedingly well with Fusion 360 users and we’re looking forward to seeing how Autodesk will spin the inevitable backlash.

(Thanks, [Jeremy Herbert] for the tip)

Remove A Speaker’s Voice From A Recording Using Ultrasound

August 12, 2022 by Maya Posch 14 Comments

What if you could effectively prevent someone from recording your voice? This is the focus of a study by Guo et al. (2022) at Michigan State University, in which they use a dynamically calculated audio signal that effectively cancels out one’s voice in a recording device. This relies on an interesting aspect of certain micro-electro-mechanical system (MEMS) microphones, which are commonly used in smartphones and other recording devices.

Pressure sensitivity of a MEMS microphone. (credit: Brian R. Elbing)

A specially crafted ultrasound signal sent to the same microphone which is recording one’s voice can result in the voice audio signal being gone on the final recording. The approach taken by the authors involves using a neural network that is trained on voice samples of the person (“Bob”) whose voice has to be cancelled. After recording Bob’s voice during a conversation, the creatively named Neurally Enhanced Cancellation (NEC) system determines the ultrasound signal to be sent to the target recording device. Meanwhile the person holding the recording device (“Alice”) will still perceive Bob’s voice normally.

As ultrasound is highly directional, the system can only jam a specific microphone and wouldn’t affect hidden microphones in a room. As noted by the authors, it is possible to do general microphone jamming using other systems, but this is legally problematic, which should not be an issue with their NEC system.

Thanks to [JohnU] for the tip!

Forget The UV Resist Mask: Expose Custom PCBs Directly On Your SLA Printer

August 9, 2022 by Maya Posch 22 Comments

For the enterprising hobbyist and prototyping hardware developer, creating custom PCBs remains somewhat of a struggle. Although there are a number of approaches to go about this, they usually involve printing or drawing a mask that is used to expose the photoresist layer on the to-be-etched PCB. Here [Andrew Dickinson]’s Photonic Etcher project provides an intriguing shortcut, by using the UV source of an MSLA 3D printer directly after converting the project’s Gerber files into a format the MSLA printer can work with.

The concept is as simple as can be: since MSLA printers essentially function by creating a dynamically updated UV mask (either via an LCD panel or DLP system), this means that an MSLA printer can be used to expose the PCB’s UV-sensitive photoresistive coating, effectively making the mask there insoluble during the etching step. This can be done with negative as well as positive photoresistive coatings, depending on the use case.

The obvious advantage of this approach is that you don’t need an additional UV source or any kind of separate mask, only an MSLA printer with a large enough work area to fit the PCB you wish to expose. One limitation of [Andrew]’s project at this point is that it can only convert Gerbers to PWMS (Photon Mono) files, but this can presumably be fairly easily extended to support more MSLA printers.

Stentrodes: A Way To Insert Brain Electrodes Without Invasive Surgery

August 4, 2022 by Maya Posch 24 Comments

When we think of brain-computer interfaces (BCIs) that use electrodes, we usually think of Utah arrays that are placed directly on the brain during open brain surgery, or with thin electrodes spliced into the exposed brain as postulated by Neuralink. While Utah arrays and kin as a practical concept date back to the 1980s, a more recent concept called Stentrodes – for stent-electrode array – seeks to do away with the need for invasive brain surgery.

As the name suggests, this approach uses stents that are inserted via the blood vessels, where they are expanded and thus firmly placed inside a blood vessel inside the brain. Since each of these stents also features an electrode array, these can be used to record neural activity in nearby neural clusters, as well as induce activity through electrical stimulation.

Due to the fact that stents are already commonly used by themselves in the brain’s blood vessels, and the relatively benign nature of these electrode arrays, human trials have already been approved in 2018 by an ethics committee in Australia. Despite lingering concerns about the achievable resolution and performance of this approach, it may offer hope to millions of people suffering from paralysis and other conditions.

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Maximum Power Point Tracking: Optimizing Solar Panels

August 3, 2022 by Maya Posch 56 Comments

When looking at integrating a photovoltaic solar panel into a project, the naive assumption would be that you simply point the panel into the general direction of where the Sun is, and out comes gobs of clean DC power, ready to be used for charging a battery. To a certain extent this assumption is correct, but feeding a solar panel’s output into something like a regular old PWM buck or boost regulator is unlikely to get you anywhere close to the panel’s full specifications.

The keywords here are ‘maximum power point’ (MPP), which refers to the optimal point on the solar panel’s I-V curve. This is a property that’s important not only with photovoltaics, but also with wind turbines and other highly variable power sources. The tracking of this maximum power point is what is generally referred to as ‘MPPT‘, but within this one acronym many different algorithms are covered, each with its own advantages and disadvantages. In this article we’ll take a look at what these MPPT algorithms are, and when you would want to pick a particular one.

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Where Pollution Hits The Road: The Growing Environmental Hazard Of Rubber Tires

July 28, 2022 by Maya Posch 110 Comments

As ubiquitous as rubber tires are due to the many practical benefits they offer to cars, trucks, and other conveyances, they do come with a limited lifespan. Over time, the part of the tire that contacts the road surface wears away, until a tire replacement is necessitated. Perhaps unsurprisingly, the material that wears away does not magically vanish, but ends up in the environment.

Because of the materials used to create tires, this worn away material is counted as a microplastic, which is a known environmental pollutant. In addition, more recently it’s been found that one additive commonly found in tires, called 6PPD, is highly toxic to certain species of fish and other marine life.

There are also indications that these fine bits of worn-off tire contribute to PM_2.5 particulate matter. This size of particulates is fine enough to penetrate deep into the lungs of humans and other animals, where they can cause health issues and exacerbate COPD and similar conditions. These discoveries raise a lot of questions about our use of tires, along with the question of whether electric vehicles stand to make this issue even worse.

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Biomimetic Surfaces: Copying Nature To Deter Bacteria And Keep Ship Hulls Smooth

July 26, 2022 by Maya Posch 24 Comments

You might not think that keeping a boat hull smooth in the water has anything in common with keeping a scalpel clean for surgery, but there it does: in both cases you’re trying to prevent nature — barnacles or biofilm — from growing on a surface. Science has looked to nature, and found that the micro-patterning formed by the scales of certain sharks or the leaves of lotus plants demonstrate a highly elegant way to prevent biofouling that we can copy.

In the case of marine growth attaching to and growing on a ship’s hull, the main issue is that of increased drag. This increases fuel usage and lowers overall efficiency of the vessel, requiring regular cleaning to remove this biofouling. In the context of a hospital, this layer of growth becomes even more crucial. Each year, a large number of hospital patients suffer infections, despite the use of single-use catheters and sterile packaging.

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