Bricked Raspberry Pi Displays History

[eN0Rm’s] Raspberry Pis are much more than just another brick in the wall. He’s used the popular embedded Linux platform to build several small rear projection screens in a brick wall (Imgur link). Brick shaped metal enclosures were mortared into the wall of the building. Each rear projection screen is illuminated by a DLP projector which sits inside the metal enclosure. The Raspberry Pis sit on a shelf below all this.  The bricks are in a building in the Aker Brygge section of Oslo, Norway, and show historical facts and short videos about the local area.

[eN0Rm] could have used a PC for this task, the price for a low-end PC with a few graphics cards probably wouldn’t have been much more expensive than several Raspberry Pi’s with cases. However, this system has to just work, and a PC would represent a single point of failure. Even if one Raspberry Pi goes down, the others will continue running.

The current installation is rather messy, but it’s just a test setup.  [eN0Rm] has already been taken to task for the lack of cable management in his Reddit thread.  As [eNoRm] says – first get it working, then make it pretty.

[Ben Krasnow] Shows us How a Crookes Radiometer Works

[Ben Krasnow] is tackling the curious Crookes Radiometer on his Applied Science YouTube channel. The Crookes Radiometer, a staple of museum gift shops everywhere, is a rather simple device. A rotor with black and white vanes rotates on the head of a needle. The entire assembly is inside a glass envelope. The area inside the glass is not at a hard vacuum, nor is it filled with some strange gas. The radiometer only works when there is a partial vacuum inside.

The radiometer’s method of operation was long misunderstood. Sir William Crookes and James Clerk Maxwell both believed that the vanes moved due to the pressure of the photons hitting the vanes. If that were true though, the radiometer would spin in the opposite direction it normally does when held near a light source.  It was eventually discovered that the system is a thermodynamic one. [Ben] proves this by cooling down the radiometer’s glass with a can of freeze spray.  The radiometer immediately begins spinning backwards, with no light source present.

From there [Ben] mounts the rotor of a radiometer inside his vacuum chamber, which many will recognize as the chamber from his DIY electron microscope. As expected, the vanes don’t spin at a hard vacuum. In fact, [Ben] find the vanes spin fastest when the pressure is about 7 mTorr.

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Multi-target IDE for 8-Bit CPUs

A long time ago, [Martin] played with old 8-bit computers. Recently, he’s been honing his assembly skills again, and the idea of an IDE for a boatload of old systems came to him. After a year of work, he announced a multitarget IDE for 8-bit computers that works in your browser.

The project is called ASM80, and includes a code editor, a workspace to put all your code, compilers for the 8080/8085, Z80, 6502, 6800 and 6809 CPUs, emulators for all these CPUs, and emulators for a few Czech computers, the ZX Spectrum, and a few of [Grant Searle]’s single board computers.

What makes this project interesting is the syntax for all the different CPUs is pretty much the same. It’s a real, modular code editor that supports macros and everything you would expect for a code editor for ancient computers.

You can check out an assembler description here. [Martin] also has an offline, desktop-based version of ASM80 called IDE80, with a video demo of that below.

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Hackaday Printing Press Upgrade

There comes a time when your movable type becomes so over-used that you no longer get a legible print off of the printing press. For months now we’ve been at work on a new site design that maintains the essence of Hackaday while ejecting the 10-year-old dregs of the site. With each small success we’ve actually ruined ourselves on viewing the old design. It is with great relief that we unveil a site design built specifically for Hackaday’s needs.

The most notable change is in the content of our landing page. For ten years, loading Hackaday.com resulted in the most recent blog posts. The blog concept is proven, but provides little opportunity to highlight quality original content and information about upcoming events. We have tried the use of “sticky” posts but honestly I find them somewhat annoying. The solution to this is not immediately apparent, but I feel we have found the most efficient solution to our complex set of needs..

We have a lot of community members who participate in Hackaday in numerous ways. Changes found in this design are driven by that fact. The landing page will, from this point forward, be a somewhat more persistent collection of notable content from the blog, our community site (hackaday.io), as well as news regarding live events, store features, contest highlights, and more. Those hard-core fans — a label I also assign to myself — will find the same reading experience as always on the new blog URL: hackaday.com/blog.

Aesthetically, we hope that all will agree the new design far supersedes the old. There was a lot to fix, and the work of the Hackaday crew who designed and implemented this new interface is truly amazing. I hope you will take the time to leave a positive comment about their work. As with any major transition, there will be some bumps in the road. Right now most of our sidebar widgets have not been migrated but that and any other problems will be fixed soon.

In this design we strived to highlight the title and image of each post to immediately convey the core concepts of the projects shown here. The author by-line and comment count remain core to the presentation of the articles, and our link style continues to be immediately apparent in the body of each article. I think we have far surpassed the readability of the comments section, in addition to the content itself. We knew we could rebuilt it… we have the technology… long live articles worth reading.

UPDATE: We are working very hard to fix all the parts that don’t look quite right. Thanks for your patience!

UPDATE 2: Infinite scrolling isn’t a feature, it’s a regression. On our test server all the blog listings were paginated just like always. When our host, WordPress VIP, pushed live the infinite scrolling manifested itself. We’ve filed a ticket with them and are hoping for a solution shortly.

UPDATE 3: Infinite scrolling has now been fixed and the blog layout now paginates. The mouse-over zoom effect has been removed. Slideshow speed has been adjusted and if you hover you mouse over a feature it will pause the scrolling.

Forkless Motorcycle Tears up the Track

The bike above may look like a pristine Yamaha prototype, but it’s actually the work of [Julian Farnam], a motorcycle hacker of the highest level. We caught his Yamaha A-N-D FFE 350 on OddBike, and you can read [Julian’s] own description of the bike on his Slideshare link.

The FFE 350 started life as a Yamaha 1990’s RZ350 two-stroke racer. From there, [Julian] gave it his own Forkless Front End (FFE) treatment. Gone is the front fork, which while common in motorcycle and bicycle design, has some problems. Fore-aft flex is one – two thin tubes will never make for a rigid front end. Changing geometry is another issue. Since forks are angled forward, the front wheel moves up and to the rear as the shocks compress. This changes the motorcycle’s trail, as well.

Forkless designs may not have these issues, but they bring in a set of their own. A forkless design must have linkages and bellcranks which are often the source of slop and vibration. [Julian’s] design uses two sets of linkages in tension. The tension between the two linkages removes most of the slop and provides that directly connected feel riders associate with forks.

The FFE 350 wasn’t just a garage queen either – it laid down some serious laps at local tracks in Southern California. Unfortunately, the forkless design was too radical to catch on as a commercial venture, and the FFE has spent the last few years in storage. [Julian] is hard at work bringing it back to its 1998 glory, as can be seen on his restoration thread over on the Custom Fighters forum.

Nanobots Swim like Scallops in Non-Newtonian Fluids

The idea of using nanobots to treat diseases has been around for years, though it has yet to be realized in any significant manner. Inspired by Purcell’s Scallop theorem, scientists from the Max Planck Institute for Intelligent Systems have created their own version . They designed a “micro-scallop” that could propel itself through non-Newtonian fluids, which is what most biological fluids happen to be.

The scientists decided on constructing a relatively simple robot, one with two rigid “shells” and a flexible connecting hinge. They 3D-printed a negative mold of the structure and filled it with a polydimethylsiloxane (PDMS) solution mixed with fluorescent powder to enable detection. Once cured, the nanobot measured 800 microns wide by 300 microns thick. It’s worth noting that it did not have a motor. Once the mold was complete, two neodymium magnets were glued onto the outside of each shell. When a gradient-free external magnetic field was applied, the magnets make the nanobot’s shells open and close. These reciprocal movements resulted in its net propulsion through non-Newtonian media. The scientists also tested it in glycerol, an example of a Newtonian fluid. Confirming Purcell’s Scallop theorem, the nanobot did not move through the glycerol. They took videos of the nanobot in motion using a stereoscope, a digital camera with a colored-glass filter, and an ultraviolet LED to make the fluorescent nanobot detectable.

The scientists did not indicate any further studies regarding this design. Instead, they hope it will aid future researchers in designing nanobots that can swim through blood vessels and body fluids.  We don’t know how many years it will be before this becomes mainstream medical science, but we know this much: we will never look at scallops the same way again!

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