3D Printed Box Gets Bigger

January 26, 2021 by 10 Comments

If you ever watched Dr. Who, you probably know that the TARDIS looked like a police call box on the outside, but was very large on the inside. When asked, the Doctor had some explanation of how something can look small when it is far away and large when it is close up, which never made much sense. However, [iQLess] has been 3D printing boxes in a small area, that fold out to be much larger boxes. (Video, embedded below.) The design comes from someone called [Cisco] who has a lot of interesting print in place designs.

You can find the design on the Prusa site or Thingiverse. The boxes do take a while to print, according to the video below. What was interesting to us, though, is that you should be able to print a design like this to create a box larger than your printer.

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Custom Bite Sensor Replaces Keyboard Expression Pedal

January 26, 2021 by 2 Comments

Sometimes, standard hardware won’t do when it comes to the differently abled. [Ben Krasnow] found himself recently working on a project for a musician who doesn’t have the use of his legs, and thus needed to create a new interface to replace a standard expression pedal.

[Ben] is a big fan of the build first method of working, and demonstrates why it works well. In this case, the first attempt involved a pneumatic design, where the user would bite down on an air bladder that actuated a remotely-located potentiometer via a tube and bellows. However, while this design worked, the tactile feedback was poor. This led to experimentation with mechanical designs, with an initial attempt involving a 3D printed mechanism and a rotary pot. This was better, but still had problems with damage from teeth and poor feel .The final design is essentially an analog button, built with fabric-impregnated silicone for wear resistance and using a linear pot for smooth feedback.

The final design is impressively tidy, and [Ben] notes that while it looks simple, it was only arrived at by trying plenty of worse solutions first. We’ve seen other work done in the gaming world too; recently, modular controllers have come into vogue to serve a wide variety of needs. Video after the break.

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Steam Engine Replica From LEGO

January 25, 2021 by 25 Comments

If engineering choices a hundred years ago had been only slightly different, we could have ended up in a world full of steam engines rather than internal combustion engines. For now, though, steam engines are limited to a few niche applications and, of course, models built by enthusiasts. This one for example is built entirely in LEGO as a scale replica of a steam engine originally produced in 1907.

The model is based on a 2500 horsepower triple-expansion four-cylinder engine that was actually in use during the first half of the 20th century. Since the model is built using nothing but LEGO (and a few rubber bands) it operates using a vacuum rather than with working steam, but the principle is essentially the same. It also includes Corliss valves, a technology from c.1850 that used rotating valves and improved steam engine efficiency dramatically for the time.

This build is an impressive recreation of the original machine, and can even run at extremely slow speeds thanks to a working valve on the top,  allowing its operation to be viewed in detail. Maximum speed is about 80 rpm, very close to the original machine’s 68 rpm operational speed. If you’d prefer your steam engines to have real-world applications, though, make sure to check out this steam-powered lawnmower.

Thanks to [Hari] for the tip!

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Avoiding PCB Crosstalk

January 25, 2021 by 13 Comments

Now that it is relatively cheap and easy to create a PCB, it is a common occurrence for them to be used in projects. However, there are a lot of subtleties to creating high-performance boards that don’t show up so much on your 555 LED blinker. [Robert Feranec] is well-versed in board layout and he recently highlighted an animation on signal crosstalk with [Eric Bogatin] from Teledyne LeCroy. If you want a good understanding of crosstalk and how to combat it, you’ll want to see [Eric’s] presentation in the video below.

Simplifying matters, the heart of the problem lies in running traces close together so that the magnetic fields from one intersect the other. The math is hairy, but [Eric] talks about simple ways to model the system which may not be exact, but will be close enough for practical designs.

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How To Run Alternative Batteries On The DJI Mavic Mini

January 25, 2021 by 40 Comments

Rechargeable batteries are ubiquitous these days, freeing us from the expense and hassle of using disposable cells. However, this has come with the caveat that many manufacturers demand their equipment only be used with their own official batteries. [aeropic] wasn’t a fan of this, so built a circuit to allow his DJI Mavic Mini to fly with any batteries he pleased.

The Mavic Mini uses I2C to communicate with official packs, making the hack relatively straightforward. [aeropic] built a board nicknamed B0B, which tells the drone what it wants to hear and lets it boot up with unofficial batteries installed. The circuit uses a PIC12F1840 to speak to the drone, including reporting voltage on the cells installed. Notably, it only monitors the whole pack, before dividing the voltage to represent the value of individual cells, but it shouldn’t be a major problem in typical use. Combined with a few 3D printed components to hold everything together, it allows you to build your own cheap pack for the Mavic Mini with little more than a PCB and a few 18650 cells.

It’s always good to see hackers getting out and doing the bread and butter work to get around restrictive factory DRM measures, whether its on music, printer cartridges, or drone batteries. We’ve even seen the scourge appear on litter boxes, too. Video after the break.

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NASA Challenge Offers Prizes For Sprouting Astronaut Food Systems

January 25, 2021 by 53 Comments

Humans have unfortunately not yet evolved the ability to photosynthesize or recharge from an electricity source, which is why astronauts well into the future of spaceflight will need to have access to food sources. Developing ways to grow food in space is the focus of the new Deep Space Food Challenge that was just launched by NASA and Canada’s Space Agency (CSA).

With a total of twenty $25,000 USD prizes for US contestants and ten $30,000 CAD prizes for the Canucks in Phase 1 of the challenge, there’s some financial incentive as well. In Phase 2, the winning teams of the concept phase have to show off their kitchen skills, and in the final Phase 3 (deadline by Fall 2023) the full food growing system has to be demonstrated.

The possible systems here would likely involve some kind of hydroponics, aeroponics or even aquaponics, to save the weight of lugging kilograms of soil into space. None of this is truly new technology, but cramming it into a package that would be able to supply a crew of four with enough food during a three-year mission does seem fairly challenging.

The NASA rules are covered in their Phase 1 Rules PDF document. While international teams are also welcome to compete, they cannot receive any prizes beyond recognition, and Chinese citizens or companies with links to China are not to allowed to compete at all.