Tracking Commercial Aircraft With Salvaged Electronics

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Early last year, [Edward] started work on an aircraft tracking system using components from old electronics he had sitting around the house. As you may or may not know, most modern aircraft continuously broadcast their current position over the 1090MHz band using the ADS-B protocol. [Edward] found that his old satellite receiver module was able to pick up the signals without too much trouble, and was more than happy to share how he did it.

The whole project cost him just under 5 Euros and requires the aforementioned satellite tuner as well as an ATMega48 microcontroller to decode the ADS-B messages. When the receiver is hooked up to a nice aerial and preamp he can listen in on planes within a 200km radius, but even with a simple piece of wire, he can locate aircraft up to 25 km away.

Raw ADS-B data isn’t terribly useful, so [Edward] put together a small application that plots nearby aircraft on a map for him. We imagine that it wouldn’t be too incredibly difficult to do the same sort of thing with the Google Maps API as well.

If you’re interested in putting together an aircraft tracking receiver of your own, be sure to swing by his site – he has a ton of useful information that will likely be a huge help along the way.

[Thanks, David]

Beginner Concepts: A Quartet Of Videos On Inductors

Inductors can be found in many of the devices you use every day, but if you’ve been working only with DC in your projects there’s a good chance you’ve never needed to know anything about them. Now’s your chance to pick up on the basics with this video tutorial series. [Afroman] put together four short videos that we’ve embedded after the break. Set aside fifteen minutes to watch them; you’ll be glad you did.

The first in the series starts out by explaining that an inductor is a coil of wire that serves a similar function as a capacitor with one major difference. A capacitor stores voltage, while an inductor stores current. In the second video, [Afroman] hooks up some inductors to a square-wave generator, then measures the resulting current characteristics using an oscilloscope. He shows the difference between inductor core material (air core versus ferrite core) and illustrates the properties that make inductors so useful as filters. The third video covers filtering circuits, and the fourth is the best explanation of why you need a flyback diode when driving a motor (an inductive load) that we’ve seen yet.

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DIY RFID Shielded Wallet Keeps Data Thieves At Bay

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[Serge] was in search of a new wallet, but he was concerned about ne’er do wells with RFID readers stealing his data. He could have gone out to the store and plunked down $20-$30 for a shielded walled, but where’s the fun in that? Instead, he decided to make his own.

Using Kevlar-Nomex fabric, he laid out the general structure for his wallet. This ultra-strong fabric has a breaking strength of 500lbs, but blocking RF isn’t exactly its forte. To provide some electromagnetic shielding, [Serge] added a nice uniform layer of silver epoxy to the Kevlar, which carries an added bonus of strengthening the material. He fired up the sewing machine, adding a nylon strip to the exterior of the wallet for reinforcement, then he worked on forming the bill pouch and card holders.

The final result is a plain yet incredibly rugged wallet that’s sure to keep his various RFID-enabled cards safe. We really dig how unassuming the wallet is – no flash, all function. Nice job, we’ll take one!

Modifying DD-WRT’s Protected GUI

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[Craig] is always keeping busy by deconstructing and poking around in various firmware images. This time around he has taken on the task of modifying the DD-WRT package, a popular replacement firmware for SOHO routers.

While the firmware is released under the GPL, [Craig] cites that it’s pretty difficult to build from source. Instead, he says that the typical course of action is to extract files from the firmware image, alter them, then reconstruct the image. This works for most things, but the DD-WRT GUI files are protected in order to prevent modification.

Since the phrase “you are not allowed to do that” doesn’t exist in his vocabulary, [Craig] set out to see if he could make his way around the protections and change the GUI code. It took quite a bit of digging around using IDA Pro and readelf, but he was eventually able to extract, tweak, then reinsert individual pages back into the firmware image.

The process is pretty time consuming, so he put together a tool called webdecomp that automates the extraction and rebuilding of DD-WRT’s web page file. If you’re interested in rocking a custom Hackaday-branded router interface like the one shown above, be sure to swing by his site and grab a copy of webdecomp.

A Solar-Powered Automatic Chicken Coop

Although we’ve featured many chicken-related hacks here, this chicken coop features a solar-powered door to save one from having to open up the coop in the morning.  As [chrisatronics] puts it “keeping chickens has one major drawback: You have to get up with them in the early morning and open the door at the coop. Everyday. Including Sundays and holidays.” This would help explain why so many people seem to be hacking their coops.

Solar power may be an interesting idea in itself, but when coupled with the fact that a chicken coop isn’t necessarily near a power supply, this becomes a very expedient solution. Controlling the setup is a MSP430 microcontroller (programming featured here for Linux) with a salvaged windshield wiper gearmotor. [Chrisatronics] did a great job writing this hack up, so if you want to try this yourself, make sure to check out the article.

Also, don’t forget to check out the video after the break for the ‘coop in action! Continue reading “A Solar-Powered Automatic Chicken Coop”

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Things To Do With Your Laptop Batteries When They’re Dead

[Roy] over at GeekDad had a dead laptop battery on his hands, and decided he would disassemble it to see what useful things he could do with the cells inside. He mentions in his article that even though your laptop might be convinced that its battery is toast, more often than not just one or two cells are damaged. This may not be news to all of our readers, but is worth pointing out to those who might not be aware.

With the bad cells separated from the good, [Roy] thought up a couple of different uses for his newly acquired batteries. His initial idea was to power an LED flashlight that was made to run on the 18650 cells he recovered from his laptop – not a stretch of the imagination, but definitely useful. The second use he came up with was to pair two of the cells together in order to simultaneously power an Arduino and some small Lego motors.

[Roy] lays out all of the standard caveats you would expect regarding the care and feeding of the lithium cells, and even suggests rebuilding the laptop battery as an option for the more skilled members of his audience.

Now we understand that dismantling and re-using old laptop cells is not necessarily groundbreaking, but it’s definitely something that’s worth a bit of discussion. [Roy] admits that his two ideas fall far short of the “18650 Things” his article title suggests, so how about adding a few of your own?

If you have stripped down some laptop batteries to salvage the cells, let us know what you did with them in the comments – we would be interested in hearing about it.

Space Camera Streams Data During Flight

Take the risk of not recovering your hardware out of a near-space camera launch by streaming the data during flight. [Tim Zaman] is part of a team that developed the rig seen above. It sent 119 image back during the recent balloon launch. This included transmissions from as high as 36 kilometers.

The main hardware included a BeagleBoard with connected Webcam housed in a Styrofoam cooler for thermal protection. Pair that with a GPS module for location tracking, and a GPRS module for data transmission and you’re in business.

But that’s not all that went up. The team built a backup hardware module in case the primary failed. This one also had a GPS and GPRS radio, but was driven by an Arduino.

The radio connection made it easy to recover the hardware. GPS data led the team directly to the landing site. The package came to rest on the roof of a building, but we guess that’s more convenient than getting snagged at the top of a huge tree.

Don’t miss the hardware detail video that we’ve embedded after the break.

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