Broken Promises Of The Wankel Engine

March 3, 2016 by 168 Comments

Through the history of internal combustion engines, there has been plenty of evolution, but few revolutions. Talk of radically different designs always leads to a single name – Wankel. The Wankel rotary engine, most notably used in automobiles by Mazda, has been around since the late 1950’s. The Wankel rotary is an example of a design which makes sense on paper. However, practical problems cause it to underperform in the real world.

Invention and History

felixwankelFelix Wankel’s engine was conceived during a dream. In it, 17-year-old Felix was driving his car to a concert. When he arrived, he bragged to his friends that his car used a new type of engine – half turbine, half reciprocating. “It is my invention!” he told his friends. Upon waking up, Wankel became dedicated to building his engine. Though he never received a formal degree (or a driver’s license), Wankel was a gifted engineer.

Young Wankel’s checkered history includes membership in several anti-semitic groups in the 1920’s. He was also involved with the founding of the Nazi party. His conflicting views on the direction of the party lead to his arrest in 1933. Eventually released through action of Hitler himself, Wankel joined the SS in 1940. The end of the war saw Wankel spending several months in a French prison for his wartime involvement.

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Overclocking The Raspberry Pi 3 For Tasty Speed Increases

March 3, 2016 by 47 Comments

Some people are never happy. [Jackenhack] got hold of a couple of shiny new Raspberry Pi 3s, and the first thing he did is to start overclocking them. Fortunately, he knows what he is doing, so none of the magic smoke escaped, but it seems not all Pis are happy with the process.

For one of the three seemingly identical Pi 3, adding heat sinks let him push the CPU from the native 1.2GHz up to 1.45GHz. That did involve a bit of overvolting (increasing the voltage to the CPU), but that can be easily done in software. He also experimented with adding heat sinks to the memory, then bumping up the speed of the memory to increase throughput. Again, he was able to make some impressive gains, bumping the speed up from the native 400 Mhz to 500 Mhz. Both of those are stable overclocks: he was able to run the system at 100% CPU load for an extended time, and has incorporated the overclocked Pi into his system that contributes to the NTP pool project.

However, when he tried the same overclock with the second of the Pi 3 victims test subjects, it failed due to the CPU overheating. So, it seems that there is a lot of variation in the individual bits of silicon on the Pi 3. Perhaps some liquid nitrogen would help? It did for an Arduino…

Incredible Marble Music Machine

March 3, 2016 by 44 Comments

We tried to figure out how to describe the band [Wintergatan]. It took a lot of googling, and we decided to let their really incredible music machine do it for them. The best part? Unlike some projects like this that come our way, [Wintergatan] documented the whole build process in an eight part video series.

The core of the machine is a large drum with two tracks of alternating grey and black Lego Technic beams and pins. The musician sequences out the music using these. The pins activate levers which in turn drop ball bearings on the various sound producing devices in the machine. The melody is produced by a vibraphone. At first we thought the drum kit was electronic, but it turns out the wires going to it were to amplify the sound they made when hit. At the end of their travel the bearings are brought up to the hopper again by a bucket conveyor.

The final part count for the machine sits at 3,000 not including the 2,000 ball bearings rolling around inside of it. If you’ve ever tried to make a marble machine, then you’ll be just as impressed as we were that the machine only appeared to lose a few marbles in the course of a three minute song. Aside from the smoothness of the machine, which is impressive, we also enjoyed the pure, well, hackiness of it. We can spy regular wood screws, rubber bands, plywood, bits of wire, and all sorts of on-the-spot solutions. Just to add bonus cool, the whole project appears to have been built with  just a bandsaw, a drill press, and a few hand power tools.

The machine is great, but we also really appreciate the hacker spirit behind it. When a commenter on a YouTube video told him he was a genius, he replied, “Thank you for that! But I do think, though, that it is mostly about being able to put in the time! I mean the talent of being stubborn and able to see things through are more important than the abilities you have to start with. If you work hard on anything, you will learn what you need and success! Its my idea anyway! So happy people like the machine!”. Which we think is just as cool as the machine itself. Video of the machine in action and part one of the build series after the break!

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A Spicy Regenerative Reciever

March 2, 2016 by 16 Comments

We recently posted a three-part series about using LTSpice to simulate electronic circuits (one, two, three). You might have found yourself wondering: Can you really simulate practical designs with the program? This quick analysis of [QRP Gaijin’s] minimalist regenerative receiver says “yes”.

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Repairing A Sony Dream Machine

March 2, 2016 by 24 Comments

Have you ever fancied a gadget but been put off by what seems like an excessive price? [leadacid44] did just that back in 2009, in his case the gadget in question was a Sony Dream Machine ICF-CL75iP. It’s an alarm clock radio, albeit a very fancy one featuring an iPod dock, SD card slot, and an electronic photo frame. Back then it was just too expensive, but in 2016 [leadacid44] spotted one on an auction site for pennies, and so snapped it up.

Of course, with something cheap there is so often a catch. In the case of this Dream Machine, it would not keep time — something pretty important in a clock. But rather than throw it on the “Hack later” pile, [leadacid44] decided to investigate, and turned up a surprising culprit. The glue Sony had used to secure the timing crystal in 2009 had become conductive with age, causing the oscillator to stop oscillating. A simple fix involving a bit of glue removal and a touch of resoldering, and the clock was back with us.

This was a very simple repair when the problem was diagnosed, but it tells us something about electronic product design, and about quality control. Sony have spent a very long time building a reputation for quality manufacture, and it is likely the Dream Machine was built with their full attention to detail. It is highly unlikely that the Sony engineers chose their crystal glue in the knowledge it would break down, after all the company is likely to make far more money selling a new TV or phone to a satisfied alarm clock owner than it is by selling them a new alarm clock. Instead it tells us that even Sony with a legendary attention to quality control can be caught out by unexpected component failures, and that as engineers we should always expect the unexpected.

So [leadacid44] has a new alarm clock, and presumably now always wakes up on time. It’s interesting to look at the Dream Machine from another perspective, to compare what was hot in 2009 with what you might see now. The Apple Dock connector for instance, or the full-size SD card. Both of which are now becoming historical curiosities, even though this device is not much more than six years old.

Over the years we’ve featured a lot of clocks, and even the odd clock radio. But this isn’t really about clock radios, and with that out of the way we’ve certainly featured a few Sony hacks.

When Life Gives You An F-15 Throttle Grip Make A Cool Joystick

March 2, 2016 by 21 Comments

We’re not certain where [NoPleaseDont] got an F-15 Throttle Grip, but it would certainly be a waste not to make something cool out of one. The F-15 is a twin engine air superiority fighter, and in it’s niche, it is one of the most successful ever made. We imagine this makes it a popular choice in air simulators.

Equipped with his successful scrounge [NoPleaseDont] decided to build a full HOTAS, Hands On Throttle and Stick, joystick. He started by taking apart the throttle grip.  As each layer was pulled a part, we were pleased to see the reassuring infestation of quality control stamps you’d expect to find on the input of a 26million dollar machine. The pinouts were presumably taken and the handle was reassembled. After that, a lot of custom sheet metal parts, 3D prints, and clever bracketry came together to form the frame of the joystick.

Finally came the electronics. Many of the photos were too blurry to decode, but at minimum a Teensy and custom LED control board is involved. The frame got a few additional buttons and control panels added.

The resulting joystick has a great history, and more buttons than we can guess the purpose of.

Google Is Building A 100kW Radio Transmitter At A Spaceport And No One Knows Why

March 2, 2016 by 154 Comments

You can find the funniest things in public government documents. There’s always ample evidence your local congress critter is working against the interests of their constituency, nation, and industry controlled by the commission they’re chairperson of. Rarely, though, do you find something surprising, and rarer still does it portend some sort of experiments conducted by Google at a spaceport in New Mexico.

In a publication released last week, Google asked the FCC to treat some information relating to radio experiments as confidential. These experiments involve highly directional and therefore high power transmissions at 2.5 GHz, 5.8GHz, 24GHz, 71-76GHz, and 81-86GHz. These experiments will take place at Spaceport America, a 12,000 foot runway in the middle of New Mexico occasionally used by SpaceX, Virgin Galactic, and now Google.

For the most part, this document only tells the FCC that Google won’t be causing harmful interference in their radio experiments. There few other details, save for what bands and transmitters Google will be using and an experimental radio license call sign (WI9XZE) that doesn’t show up in the FCC database.

Of the few details listed in the documents, one thing does pop out as exceptionally odd: a 70-80 GHz transmitter with an effective radiated power (ERP) 96,411 W. That’s close enough to 100 kilowatts to call it as such. This is the maximum effective radiated power of the highest power FM stations in the US, but radio stations are omnidirectional, whereas Google is using very high gain antennas with a beam width of less than half a degree. The actual power output of this transmitter is a mere half watt.

The best guess for what Google is doing out in the New Mexico desert is Project Skybender, a project to use millimeter waves to bring faster Internet to everyone. There aren’t many details, but there is a lot of speculation ranging from application in low Earth orbit to something with Google Loon.