[Ben Krasnow] Shows Us How A Crookes Radiometer Works

November 15, 2014 by Adam Fabio 21 Comments

[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

November 15, 2014 by Brian Benchoff 19 Comments

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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Complete FPV Setup For Your Drone

November 15, 2014 by Mike Szczys 17 Comments

[Ioannis] is like anyone else who has a quadcopter or other drone. Eventually you want to sit in the cockpit instead of flying from the ground. This just isn’t going to happen at the hobby level anytime soon. But the next best option is well within your grasp. Why not decouple your eyes from your body by adding a first-person video to your quad?

There are really only four main components: camera, screen, and a transceiver/receiver pair to link the two. [Ioannis] has chosen the Sony Super HAD CCTV camera which provides excellent quality at the bargain basement price of just $25 dollars. A bit of patient shopping delivered a small LCD screen for just $15. The insides have plenty of room as you can see. [Ioannis] connected the screen’s native driver board up to the $55 video receiver board. To boost performance he swapped out the less-than-ideal antenna for a circular polarized antenna designed to work well with the 5.8 GHz radio equipment.

It seems that everything works like a dream. This all came in under $100 which is half of what some other systems cost without a display. Has anyone figured out a way to connect a transmitter like this to your phone for use with Google Cardboard?

Morse Decoder’s Lean And Sexy Search Algorithm

November 15, 2014 by Mike Szczys 27 Comments

Often the Morse Code centered projects that we feature are to help you practice transmitting messages. This one takes a tack and builds an automatic decoder. We think [Nicola Cimmino’s] project is well worth featuring simply based on his explanation of the Digital Signal Processing used on the signal coming in from the microphone. Well done. But he’s really just getting warmed up.

What makes this really stand out is a brilliant algorithm that allows conversion from Morse to ASCII using a lookup table of only 64 bytes. This provides enough room for A-Z and 0-9 without chance of collision but could be expanded to allow for more characters. Below is a concise description of how the algorithm works but make sure you take the time to read [Nicola’s] project description in its entirety.

The algorithm can be decribed as follows. Have an index inside the lookup string inizialied to zero. Have an initial dash jump size of 64. At every received element (dot or dash) halve the initial dash jump and then increase by 1 the index inside the lookup string if a dot was received and by dash jump size if a dash was received. Repeat until a letter separator is reached, at that point the index inside the lookup string will point to the ASCII corresponding to the decoded morse.

Have you heard of this technique before? If so, tell us about it in the comments below. Before you jump all over this one, realize that Magic Morse uses a different technique.

Hiding Executable Javascript In Images That Pass Validation

November 15, 2014 by Mike Szczys 18 Comments

Here’s an interesting proof-of-concept that could be useful or hazardous depending on the situation in which you encounter it. [jklmnn] drew inspiration from the work of [Ange Albertini] who has documented a way to hide Javascript within the header of a .gif file. Not only does it carry the complete code but both image and the Javascript are seen as valid.

With just a little bit of work [jklmnn] boiled down the concept to the most basic parts so that it is easy to understand. Next, a quick program was written to automate the embedding of the Javascript. Grab the source code if you want to give it a try yourself.

Let’s get back to how this might be useful rather than harmful. What if you are working on a computer that doesn’t allow the browser to load Javascript. You may be able to embed something useful, kind of like the hack that allowed movies to be played by abusing Microsoft Excel.

Electronica 2014 Wrap-Up

November 15, 2014 by Brian Benchoff 21 Comments

Make no mistake about it, Electronica is a real trade show, with suits everywhere, meeting rooms packed to the gills, and €4 bottles of soda. If you dig around long enough, you will find some interesting things, as I did on my excursions to the Messe with [Chris Gammell] and [Sprite_TM].

Actual cool booths

This isn’t a show and tell. The purpose of the booths are for sales people to meet with other sales people, and people who have the letter ‘C’ somewhere in their title to be concerned about things you’ll never understand. Booth displays are a plastic case with a few components in them. If you’re lucky, you’ll have some units running on a table somewhere.

This isn’t the case for all booths, though. The Linear booth wanted to demo some custom sensors, so they built the most primitive thermocouple in existence. It’s a piece of copper pipe and some barbed wire, brazed together. It won’t be an accurate thermocouple when the torch is still hot, but by calibrating it against a known temperatures and values, they can get pretty reliable temperature readings. Oh, the displays are Nixies.

Barbed wire copper pipe thermocouple. Those are just brazed together.

The temperature calibration for this particular resistor

Nixie junkyard thermocouple

Raspberries

No, Raspberry Pi didn’t have a booth, but RS Components did, and this is where you could find Raspberries and Raspberry-related projects. I hun around the booth after [Eben] gave a talk, and this is what the future of the Raspberry Pi ecosystem will look like:

There will be no more form factor changes. Until the next hardware update, we’ll have the B+ and A+ form factor.
When is the next hardware update? Some time in 2017 or 2018. They don’t have a chip selected yet.
Four million units shipped. I told [Eben] the Commodore 64 shipped 25 Million, [Eben] told me [Jack Tramiel] was running his mouth when he said that. German tank problem with serial numbers and all that.
Lots of industrial applications. There are real, legitimate uses of a Pi in controlling million dollar machines.
No one has built a cluster of Pi compute modules. I believe the problem is finding vertical SO-DIMM connectors.

The latest from the FTDI display case

Free Stuff

Show up at the end of Electronica, and you’ll quickly figure out the people at booths don’t want to ship their stuff home. This was the Hammond Enclosures booth:

What did I grab? Just some Raspi cases, and one of the wooden Hammond enclosures used for tube amps. Also picked up a sample of unreleased Kailh switches for mechanical keyboards. Data coming sometime.

If someone is at the Munich airport in a few days, I might have a wooden Hammond enclosure for you.

Hand-Machined Companion Cube Can Be Destroyed And Rebuilt

November 15, 2014 by Theodora Fabio 7 Comments

[Michael Gainer] is a big fan of Portal, and it shows in the Weighted Companion Cube he made. [Michael] hand-machined the many pieces that comprise the Cube’s body and medallions out of 6061 aluminum. Dykem was used to transfer the marks for accurate machining, and the color is powder-coated to a heat tolerance of 400F. A CNC was used to make the distinctive hearts. [Michael] notes the irony was “very Portal” in having them cut by a heartless machine when everything else was done manually. The attention to detail is striking, the level of design more so when [Michael] proceeds to incinerate the poor Companion Cube with a brush burner. In the video shown at the link above, the Cube falls apart as the glue holding it together melts. When all is said and done, just grab more glue to bring that Cube back to its six-sided glory. Repeat to your heart’s content. Huge success! We have to be honest, after seeing all those pieces, we aren’t sure we’d want to do this very often. Companion Cubes have been featured in various iterations on Hackaday before, but they were never built with the idea of repeatedly destroying and rebuilding them. This novel take would make GlaDOS proud.

[Michael] has plans to put an Android device inside it with some light and temperature sensors. He wants to give it a voice resembling Portal’s turrets so it can whine when it needs to be charged or scream when it’s too hot or cold. He dubs this next project the “Overly Attached Weighted Companion Cube.” It wouldn’t be a good idea to incinerate this upcoming version, though we’d probably be inclined to if it demanded so much of our attention!