Listening To Aircraft Transponders With A Raspberry Pi

May 23, 2013 by Brian Benchoff 31 Comments

Last year’s big hack was software-defined radio; a small USB TV tuner that could listen in on radio broadcasts anywhere between 64 and 1200 MHz. This year, it’s all about the Raspberry Pi, so it’s surprising we’re only just now seeing a mashup of these two pieces of hardware. [Corq] is using a Raspi and RTLSDR TV tuner to listen in on aircraft transponders, and getting a whole bunch of data from aircraft flying overhead.

Even though the ADS-B decoder [Corq] is using is written for OS X, he’s reading the data coming from the USB TV tuner over the network with a program called Dump1090. This program allows [Corq] to attach his SDR to a Raspbery Pi and put it somewhere the antenna will get good reception – an attic, or an outdoor weatherproof case – and stream data to his desktop over a WiFi or network connection.

With a USB TV tuner and a Raspberry Pi, [Corq] is able read the tail numbers, altitude, latitude, longitude, speed, heading, and even the type of aircraft currently flying over his house. That’s cool enough, but the fact that he can effectively do this over the Internet makes it a brilliant hardware mashup.

Wireless Microcontroller/PC Interface For $3

May 19, 2013 by Brian Benchoff 48 Comments

Sending data from a microcontroller to a PC usually requires some sort of serial connection, either through fiddly on-chip USB, FTDI chips, or expensive radio ICs. [Scott] didn’t want to deal with this when creating a network of wireless temperature sensors, so he hacked up a few cheap 433 MHz radio transmitters and receivers to transmit data to a PC for about $3.

After sensor data is collected on a microcontroller and sent over radio, there’s still the issue of getting it into a PC. For this, [Scott] piped the data into the microphone port of a cheap USB sound card. We’ve seen this trick before both in the world of microcontrollers and loading programs onto a Commodore 64 via a cassette interface.

Once the data is sent into the sound card, it’s decoded with a a small Python app. Given the range and quality of the RF transmitters and receivers [Scott] says it’s not an extremely reliable way to send data to a PC. It is cheap, though, and if you need to read sensors wirelessly on a budget, it’s hard to do much better.

Check out [Scott]’s demo of his creation below.

[youtube=http://www.youtube.com/watch?v=GJHFldPwZvM&w=580]

Retrotechtacular: First Laser Transmitter Built 50 Years Ago

May 14, 2013 by Mike Szczys 15 Comments

helium-neon-laser-transmitter

Most of the time we feature hokey film footage in our Retrotechtacular series, but we think this hack is as cool today as it was fifty years ago. [Clint] wrote in to tell us about Operation Red Line. It was an experiment performed May 3rd and 4th, 1963, which means the 50th anniversary just passed a few weeks ago. The hack involved sending data (audio in this case) over long distances using a laser. But back then you couldn’t just jump on eBay and order up the parts. The team had to hack together everything for themselves.

They built their own helium-neon laser tube, which is shown on the right. The gentlemen involved were engineers at a company called Electro-Optical System (EOS) by day, and Ham radio enthusiasts by night. With the blessing of their employer they were able to ply their hobby skills using the glass blowing and optical resources from their work to get the laser up and running. With that side of things taken care of they turned to the receiving end. Using a telescope and a photomultipler they were able to pick up the beam of light at a distance of about 119 miles. The pinnacle of their achievement was modulating audio on the transmitter, and demodulating it with the receiver.

[Clint] knows the guys who did this and wrote up a look back at the project on his own blog.

Tracking Ships Using Software-defined Radio (SDR)

May 6, 2013 by Mike Szczys 19 Comments

tracking-ships-using-sdr

When we first started hearing about software-defined radio hacks (which often use USB dongles that ring it at under $20) we didn’t fully grasp the scope of that flexibility. But now we’ve seen several real-life examples that drive the concept home. For instance, did you know that SDR can be used to track ships? Ships large and small are required by may countries to use an Automatic Identification System (AIS) transponder. The protocol was originally developed to prevent collisions on large ships, but when the cost of the hardware became affordable the system was also brought to smaller vessels.

[Carl] wrote in to share his project (which is linked above). Just like the police scanner project from April this makes use of RTL-SDR in the form of a TV tuner dongle. He uses the SDRSharp software along with a Yagi-UDA. The captured data is then decoded and plotted on a map using ShipPlotter.

Retrotechtacular: History Of The U.S. Antiballistic Missile Systems

April 30, 2013 by Mike Szczys 43 Comments

retrotechtacular-missle-defense

On this installment of Retrotechtacular we’re taking a look at the history of the United States Antiballistic Missile System. The cold war was a huge driver of technological development, and this missile defense is a good example. At its most basic this is a radar system capable of tracking objects in three dimensions. It utilizes separate transmitters and receivers which are synchronized to rotate at the same time.

The movie, which is about forty-five minutes, came to our attention because of [Dammitd’s] interest in the Luneburg Lens used by the system. At about 11:10 into the video after the break this component is discussed. Inside a dome like the one seen above is a reflector made of blocks of polystyrene foam which has been laced with bits of metal. This lens is stationary, with the receiver rotating around it to collect the transmitter’s waves as the echos bouncing off an object in the sky are focused by the lens.

Continue reading “Retrotechtacular: History Of The U.S. Antiballistic Missile Systems” →

SDR As A Police And Fire Radio Scanner

April 25, 2013 by Mike Szczys 48 Comments

If you’ve lost interest in that DVB dongle you bought to give software defined radio a try you should bust it back out. [Harrison Sand] just finished a guide on how to use SDR to listen in on Police and Fire radio bands.

The project, which results in the crystal clear audio reception heard after the break, uses a whole lists of packages on a Windows box to access the emergency bands. SDRSharp, which has been popular with other DVB dongle hacks, handles the hardware work. In this case the dongle is a Newsky TV28T v2 module that he picked up for a few bucks. He’s also using some support programs including the Digital Speech Decoder which turns the data into audio.

We wonder how many areas this will work for. It was our understanding that law enforcement was moving to encrypted communications systems. But all we really know about it is that you can jam the system with a children’s toy.

Continue reading “SDR As A Police And Fire Radio Scanner” →

Turning An Easter Egg Hunt Into A Fox Hunt

April 4, 2013 by Brian Benchoff 4 Comments

fox

We’ve seen [Todd Harrison]’s work a few times before, but he’s never involved his son so throughly before. This past Easter, he thought it would be a good idea for his son and a few of his friends to take part in an easter egg hunt. Being the ham he is, he decided to turn an easter egg hunt into an adventure in radio direction finding, or as amateur radio operators call it, a fox hunt.

[Todd] put together a great tutorial on building a yagi – a simple directional antenna – out of a couple of pieces of PVC pipe and a few aluminum and brass rods. With this and a handheld ham set, [Todd] hid a fox along with a stuffed easter bunny and a basket of candy near a local park. Operating under the guidance of his dad, [Todd]’s son and his friends were eventually able to find the fox. Leaving candy out in the Arizona sun probably wasn’t [Todd]’s best idea – the fox, and candy, were covered in ants when they were found – but it was a great introduction to amateur radio.