Month: September 2011

Tracking Commercial Aircraft With Salvaged Electronics

September 22, 2011 by 56 Comments

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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

September 22, 2011 by 18 Comments

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.

Continue reading “Beginner Concepts: A Quartet Of Videos On Inductors” →

Retro-gaming Wall Art; It’s Playable!

September 22, 2011 by 15 Comments

Here’s a wall hanging for the reception area that let’s your customers play retro games while they wait. To give you some sense of scale, the buttons to the right (labeled Start/Jump but we would call them A and B) are arcade buttons larger than traditional arcade buttons. The screen itself is a Samsung widescreen computer monitor — we’d wager that it’s a 16″ model but we’re just guessing. It’s held in the wooden frame by a piece of angle bracket.

This is the product of a hack we looked at in June where an Arduino was used to control digitized retro LCD games. The same hardware is used, monitoring the buttons with the Arduino and using a Python script to translate them to keypresses on a computer. That means this isn’t a standalone, but needs a computer to run the game and feed the LCD monitor. Still, we love the look of it and hold out hope that this will someday migrate to FPGA control (they have not problem driving LCD screens) with selectable games.

ATtiny Hacks: DIY High-speed Photography LED Lighting Rig

September 22, 2011 by 7 Comments

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[Tom] wanted to try his hand at high-speed photography and needed some equipment to get things rolling. Not wanting to spend a ton of money on a lighting rig or trigger mechanism, he decided to build his own. In a three part series on his blog, he details the construction and testing of his high-speed setup along with the improvements and lessons learned along the way.

His adventures started out with a small off-brand Cree LED clone and an ATiny15L that was collecting dust in his workshop. He built a simple circuit that would trigger the LED to light his subject, which in [Tom’s] case was a bowl of milk. Rather than using a motion or sound trigger, he opted to mount a small piezo to the bottom bowl, firing the LED any time a droplet hits the bowl’s surface.

The pictures he took were decent, but he knew he could get better results. He purchased a new, more powerful Cree LED, and wrote a small terminal program that allows him to tweak his flash parameters using his laptop. The results he gets now are far better – in fact, he has a whole gallery of pictures you can check out.

If you want to delve into high-speed photography as well, all of the schematics and code can be found on his blog.

DIY RFID Shielded Wallet Keeps Data Thieves At Bay

September 22, 2011 by 39 Comments

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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!

Laser Cut Clock Reminds Us Of A Spirograph

September 21, 2011 by 19 Comments

[Brian] from Louisville’s LVL1 hackerspace sent in this laser cut gear clock that’s almost unlike any other clock we’ve seen before. [Brian] also put up a wonderful Instructable for his build.

Since LVL1 got a better laser cutter a lot of neat projects have been piling up. [Brian] based his clock around two cheap stepper motors driven by a freeduino. A chronodot was used to keep accurate time. Making the gears, though, presented a few problems. While prototyping the gear clock face, it was apparent that the numbers should be oriented along a line coming from the center of the gear. The prototype also used 100 teeth and that didn’t translate well into a clock design. [Brian] designed the minute gear with 60 teeth, and the hour gear with 144 teeth so that each tooth would equal 5 minutes.

[Brian]’s clock is functionally similar to this $2500 gem, and certainly much less expensive even after the cost of the laser cutter is taken into account. Of course, the Spirograph clock keeps track of minutes so it may be worth upwards of $5k.

Modifying DD-WRT’s Protected GUI

September 21, 2011 by 29 Comments

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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.