Bicycle Flywheel Stores A Bit Of Energy, Not Much

May 30, 2021 by Zoe Skyforest 49 Comments

Kinetic energy recovery systems have often been proposed as a useful way to improve the efficiency of on-road vehicles, and even used to great effect in motorsports for added performance. [Tom Stanton] decided to build one of his own, outfitting a simple bicycle with a flywheel system for harvesting energy. (Video, embedded below.)

The system consists of a 300 mm steel flywheel mounted in the center of the bike’s frame. It’s connected to the rear wheel via a chain and a clutch which [Tom] assembled himself using bicycle disc brake components. The clutch is controlled by a handlebar lever, allowing the rider to slow the bike by charging the flywheel, or to charge the flywheel to maximum speed by pedalling hard with the clutch engaged.

The actual utility of the flywheel is minimal; [Tom] notes that even at its peak speed of 2200 RPM, the flywheel stores a small fraction of the energy content of a AA battery. Practical demonstration shows the flywheel is only able to deliver a small push to [Tom] when riding the bike, too.

Despite the lack of performance, it’s nonetheless an interesting project and one that demonstrates the basic principles of flywheel energy storage. The underwhelming results perhaps serve as a solid indication of why it’s not something we use particularly often, on bicycles at least. We’ve seen [Tom]’s bike experiments before, too. Video after the break.

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Solar Plane Is Like One Big Flying Solar Panel

May 29, 2021 by Zoe Skyforest 15 Comments

Solar-powered plane concepts typically focus on high-efficiency glider-type designs, so as to make the best possible use of the limited power available from the sun. [rctestflight] wanted to try a different school of thought, instead building a relatively inefficient plane that nonetheless packed a huge amount of solar panels on board.

The plane consisted of a pizza-box style design, with a simple foam rectangular wing that was absolutely covered in solar panels. The plane was controlled with an off-the-shelf autopilot, and fitted with cheap, no-brand MPPT modules to handle charging the batteries. The plane faced difficulties in flight, most often with stability, which led to the autopilot getting the plane lost on one occasion. However, one flight was achieved with a full one hour and thirty minute duration, indicating the solar panels were helping to extend flight times beyond what was capable with batteries alone.

Further research on the ground showed that the cheap MPPT modules were wasting power, and there was more to be had. A better MPPT module was subbed in and showed that the panels could generate up to 5 amps under good conditions, while the plane only needed roughly 4.2 amps to fly. This would allow for indefinite flight in sunny conditions, though probably would not allow enough energy to be banked to fly 24 hours round the clock due to the lack of power at night.

We’ve followed [rctestflight]’s solar plane experiments for a while now, and can’t wait to see the next iteration. Video after the break.

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3D Printing A Centrifugal Water Pump

May 28, 2021 by Zoe Skyforest 43 Comments

Once upon a time, 3D printing was about churning out tiny Yodas and Pikachus, but these days, useful things are regularly 3D printed too. A great example is this centrifugal water pump that can really deliver the juice, courtesy of [Connor].

The pump’s housings and impeller are all 3D printed in PLA, as well as the inlet which is designed for a 2L soda bottle to screw into. Gaskets are printed in pliable TPU to help seal the housings. There are a few ball bearings inside to allow the impeller to spin nicely, too, with hex head fasteners used to hold everything together and a long bolt used as the main impeller shaft. Notably, no shaft seal is included, so the pump does leak a bit, but it’s not a major concern assuming you’re just pumping water and don’t mind spilling a bit of excess. Turned with a drill at 1800 rpm, the pump is able to achieve a flow rate of 13 litres per minute, or a maximum head of 1.2 meters. The design is on Onshape, for the curious.

It’s a great example of how 3D printing can allow the creation of machines with complex geometry without the need for advanced machining skills. Instead, all the hard work is done on the CAD side of things. We’ve seen 3D printed pumps put to real work before, too, like this fertilizer dispenser. Video after the break.

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Can You Hot-Swap Flash Chips In A Consumer Router?

May 28, 2021 by Zoe Skyforest 29 Comments

Sometimes, you mess up when toying with the firmware of an embedded device and end up “bricking” what you were working on. [Chris Bellows] had done just that with a consumer router, corrupting the onboard NAND flash to the point where recovery via normal means was impossible. Armed with a working duplicate of the router, he wondered if the corrupted NAND flash could be substituted into the working router while it was running, and reflashed in place – and decided to find out.

Key to achieving the hack was finding a way to remove the existing NAND flash in the working router without crashing the system while doing so. This required careful disconnection of the chip’s power lines once the router had booted up, as well as tying the “Ready/Busy” and “Read Enable” pins to ground. With this done, the chip could carefully be removed with a hot air tool without disrupting the router’s operation. The new chip could then be soldered in place, and flashed with factory firmware via the router’s web interface. At this point, it could be powered down and the chips swapped normally back into their own respective routers, restoring both to full functionality.

It’s a neat hack, and one that shows that it’s sometimes worth taking a punt on your crazy ideas just to see what you can pull off. It also pays to know the deeper secrets of the hardware you run on your own home network.

TNDLPT Brings Tandy Sound To Any DOS Computer

May 27, 2021 by Zoe Skyforest 9 Comments

The Tandy 1000, among other contemporary computers and consoles of the 1980s, used the Texas Instruments SN76489 for its sound and musical output. This venerable sound chip can now be used on virtually any DOS machine, as long as it has a parallel port – thanks to the TNDLPT adapter!

The adapter consists of the SN76489, hooked up to the parallel port so that it can be addressed by the host computer via a DOS Terminate and Stay Resident program acting as a driver. With the TSR loaded, classic DOS games can be used with the TNDLPT sound output by simply selecting the Tandy 1000 soundcard at install. It can also be used in a variety of other ways, such as with the TNDY tracker for music creation, or the SBVGM soundtrack player.

For those eager to hear the soaring 3 voices (and one noise channel!) of the SN76489 once again, this is a great way to do it, with kits available on the Serdashop site for those wishing to solder up their own. Alternatively, get a different vibe with the OPL2 instead. Video after the break.

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Deep Learning Enables Intuitive Prosthetic Control

May 27, 2021 by Zoe Skyforest 7 Comments

Prosthetic limbs have been slow to evolve from simple motionless replicas of human body parts to moving, active devices. A major part of this is that controlling the many joints of a prosthetic is no easy task. However, researchers have worked to simplify this task, by capturing nerve signals and allowing deep learning routines to figure the rest out.

The prosthetic arm under test actually carries a NVIDIA Jetson Nano onboard to run the AI nerve signal decoder algorithm.

Reported in a pre-published paper, researchers used implanted electrodes to capture signals from the median and ulnar nerves in the forearm of Shawn Findley, who had lost a hand to a machine shop accident 17 years prior. An AI decoder was then trained to decipher signals from the electrodes using an NVIDIA Titan X GPU.

With this done, the decoder model could then be run on a significantly more lightweight system consisting of an NVIDIA Jetson Nano, which is small enough to mount on a prosthetic itself. This allowed Findley to control a prosthetic hand by thought, without needing to be attached to any external equipment. The system also allowed for intuitive control of Far Cry 5, which sounds like a fun time as well.

The research is exciting, and yet another step towards full-function prosthetics becoming a reality. The key to the technology is that models can be trained on powerful hardware, but run on much lower-end single-board computers, avoiding the need for prosthetic users to carry around bulky hardware to make the nerve interface work. If it can be combined with a non-invasive nerve interface, expect this technology to explode in use around the world.

[Thanks to Brian Caulfield for the tip!]

One Inkscape Plugin Collection To Rule Them All

May 27, 2021 by Zoe Skyforest 40 Comments

Inkscape is an amazing piece of open source software, a vector graphics application that’s a million times more lightweight than comparable commercial offerings while coming in at the low, low price of free. The software also has plenty of extensions floating around on the Internet, though until now, they haven’t been organised particularly well. The MightyScape project aims to solve that, putting a bunch of Inkscape plugins into one useful release.

The current MightyScape release has a whole bunch of useful stuff inside, for tasks as varied as laser cutting, 3D printing, vinyl cutting, as well as improvements on areas where Inkscape is a bit weak out of the box – like CAD, geometry and patterning. The extensions are maintained and working, albeit with some bugs, and are intended for use with Inkscape 1.0 and above.

The aim is that by creating an overarching collection, the MightyScape project will help inspire the community to come together and actively maintain Inkscape plugins rather than allowing them to wither and die when forgotten by their original creators. That’s the benefit of open-source, after all – you can do whatever you want with the software when you have the code to do so!