Rotary and cordless phones mashup

This pile of hardware marries telecommunications hardware from distinctly different generations. [Andrew D. Farquharson] wanted the retro look and operation of a rotary phone, with the convenience of a modern cordless. He combined the two technologies to achieve his goal.

The first problem was to find a way to translate the rotary inputs to something he could use. There are already a bunch of projects that use rotary hardware so he didn’t have to reinvent the wheel. He followed this guide to connecting Arduino to a rotary phone.

The next step was to interface with his cordless phone. He ditched the case and soldered rainbow ribbon cable to the entire button matrix. An opto-isolator is used to protect the Arduino while making each connection. Finally, he patched into the mechanism which monitors the cradle to see if the handset has been picked up. It sounds like his code lets you enter the number on the dial, then pick up the handset to actual transmit it through the cordless phone.

Cheetah robot can run down even the fastest of us

It’s a blur, but you really don’t want to seen this thing coming for you anyway. It’s the latest look at what the folks at Boston Dynamics have been working on under a DARPA contract. They call it the Cheetah robot as it’s the fastest four-legged bot ever developed. The clip after the break shows it breaking the world record over 100 meters… for a human. This isn’t really legitimate since the run is done on a treadmill and the robot is tethered. But it’s still impressive scary.

The Cheetah is a relative of BigDog, another Boston Dynamics robot which we’ve seen several times in the past. BigDog specializes in lifting heavy loads and traversing rough terrain. We don’t think it will be too long before both traits can be “bred” into one device. A lot of times when we feature these robots there are comments about how they invoke images from The Terminator movies. For us this is more along [Michael Bay's] vision of robots from the Transformers series. It certainly not small enough or fast enough to be seen as an early version of the Rat Thing.

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Scratch-built RFID reader

We never bought an RFID reader because it seems too simple to be all that much fun. But [Abdullah] really caught our eye with his latest project. It’s an RFID reader built from discrete parts, and that’s an adventure we can get behind!

His write-up dives right into the theory of the device. He wrapped his own coil, which measure about one microhenry, then shares an equation used to calculate the appropriate capacitor pair for it. This is fed by a 125 kHz oscillator and works as the most basic reader. In practice this needs more components for rock-solid operation and he quickly moves to a marginally more complicated circuit which still does exactly the same thing.

He is now able to detect RFID tag data by reading this circuit with an oscilloscope. But the signal is very very weak. The rest of the post focuses on how to best utilize an OpAmp to increase signal quality and on/off time.

If you’re looking to recreate his reader [Abdullah] included a Kicad schematic and board layout.

Adding ePaper navigation data to a sailboat

[Mike Holden] has been on the hunt for a display that is easy to read in bright sunlight. He wants to use it to read out navigational data on his sail boat. The best option is an ePaper display. He managed to build a system that will feed updating NMEA 0183 data to a Nook Simple Touch.

NMEA 0183 is a protocol that governs data from marine navigational equipment. The most obvious is GPS, but there are a lot of possibilities like sonar, a gyrocompass, and an autopilot. To get things rolling he wrote an Arduino sketch which generates dummy packets using the standard. This let him develop and test the system without being near any of the real equipment. The heart of the build is a WiFi router. It pulls in the data over a USB port using an RS232 to USB converter cable. A Python script parses the data and generates a webpage which refreshes the data every second. This is loaded using Opera browser on the Nook

Check out the video after the break to see a demo of the system.

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Researching cosmic rays with cloud chambers

In the late 1940s, the US Naval Research Laboratory used a few German-built V2 rockets to study cosmic rays from above Earth’s atmosphere. To do this, a nitrogen-powered cloud chamber was fitted inside the nose cone of these former missiles, sent aloft, and photographed every 25 seconds during flight. When [Markus] read about these experiments, he thought it would be an excellent way to study cosmic rays from a high altitude balloon and set about building his own Wilson cloud chamber.

Cloud chambers work by supersaturating the atmosphere with water or alcohol vapor. This creates a smoky cloud inside the chamber, allowing for the visualization of radiation inside the cloud. Usually the clouds in these chambers are made in a very cold environment using dry ice, but rapidly decreasing the air pressure in the chamber will work just as well, as [Markus] discovered.

[Markus]‘s small cloud chamber uses a CO2 cartridge to provide the pressure in the cloud chamber before dumping the CO2 out of the chamber with the help of a solenoid valve.

In the video after the break, [Markus] demonstrates his cloud chamber by illuminating the cloud with a laser pointer and introducing a few alpha particles with a sample of Americium 241. It looks very cool, and seems to be useful enough to count cosmic rays aboard a balloon or amateur rocket.

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Mixing video for old school effects

For all the high production values Final Cut Pro and Adobe Premier have released upon the world, there’s still a cinematographic aesthetic only possible with analog video, linear editing, and video feedback. [gijs] just sent in a video mixer he’s been working on to allow crossfading between two video signals and introducing some very cool analog video distortion effects.

[gijs]‘ mixer uses the LM1881 video sync separator also found in the Arduino video experimenter shield. Because two different video feeds are unlikely to send their sync signal at exactly the same time, the selected video will stay still on the screen while the second video feed will slowly scroll horizontally across the screen.

This isn’t the first analog video hack [gijs] has come up with; last year he released an Arduino video sampler capable of recording about a second of video and playing it back forward, reverse, looped, or inverted.

We’re sure combing both the video mixer and sampler would produce an aesthetic similar to the experimentation seen on 80s-era public access or our time in AV club. Either way, a very cool build that just can’t be done digitally.

Video of the mixer after the break.

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Saving the ISS by hacking a toothbrush


We absolutely love these stories of hacker ingenuity saving peoples lives. In this case, it was aboard the ISS, and the item being hacked was a toothbrush.

The story is as follows. Some equipment failed, as space junk tends to do, and the astronauts found themselves needing to do some repairs. Upon inspection, they couldn’t remove some modules due to an accumulation of “space dust” around some bolts.  This was especially troubling as the unit in question was something that was supposed to route power from some of the solar arrays to the ISS. Even more troubling is that another unit failed while they were assessing the situation.

Realizing they had to act fast so as not to lose too much power to function, they cobbled together some tools to allow them to clean out the access ports and remove the units for repair. A task that sounds like an easy solution here on earth proved to be life threatening in space. Eventually though, their makeshift tools came to the rescue and they were able to repair and restore power.