[h. p. friedrichs] (AC7ZL) has some great plans for building a crystal radio. The stator coil and output coil are wrapped around the outside of a CDR sleeve. The tuning capacitor is constructed by sandwich two clear CDs between metal and attaching this inside the top of the sleeve. The rotor shaft is mounted using the bushings from a pair of disassembled potentiometers. A hot needle is used to tap the stator coil through the housing every fifth turn. Even though the parts aren’t very traditional it looks like a really solid radio. He’s got instructions for building a matching ear piece out of tea tins too.

Continue reading “Crystal Radio Built From Modern Junk” →

Reader [Krome] wanted a reliable, modular, weather proof WiFi bridge. The outer weather box was purchased for $50. The main radio is a proprietary Wi-Lan HP45-24. A lightning arrestor is included because this proprietary box was purchased before the WiFi band was official allocated and would be hard to replace. A Linksys WRT54G is used as the local access point and is connected to a Hyperlink 500mW amplifier. The Wi-Lan box and the amplifier have their antennas connected to panel connectors on the outside of the box. The WRT and Wi-Lan box are both powered by an ATX power supply while the amp is connected to the pass-through. Looks like a really solid setup and it should be easy to replace individual components if they fail.

Continue reading “All-weather WiFi Enclosure” →

Wondering how to get the best performance out of your homebrew WiFi antennae? This homebuilt SWR meter will help you measure and match the impedance of your antennae with your source. A good match will ensure maximum power transfer. Use the full schematics or you can just buy the meter from the site.

Continue reading “Homebrew SWR Meter” →

RC helicopters have become so cheap that they’re now a really attractive robotics platform. This guide gives a jumping off point for starting your own project. It covers how to integrate a Gumstix embedded linux system into the helicopter. Code is provided so that you can hook up a usb controller to your laptop and control the helicopter over Bluetooth. All you need to do after that is build some cool controls, hook up a speaker and start streaming Ride of the Valkyries.

[thanks Neurolizer]

Continue reading “Computer Controlled RC Helicopter” →

Okay, if yesterday’s hack didn’t turn your stomach, this one will. It was inspired by this previous feature hack. After splitting open the PDA and a secure digital wifi card you solder the two together. When you are done you should have a PDA with built in wifi and an open SD card slot. I guess it works, but how is it that simple?

[thanks Dave]

Continue reading “PDA SD Expansion” →

Defcon isn’t the only hacker gathering starting up right now. If you are at What The Hack in the Netherlands you might catch a glimpse of this project. It’s a wardriving box based on the WRAP. The platform is similar to the Soekris boards and the site actually describes both. It isn’t a complete how to, but you’ll have a good idea of what’s in store for you if you want to attempt this.

[thanks ian]

Continue reading “Wardriving Box” →

I was pretty sure this could be done, but hadn’t seen anyone pull it off till now. Bird603568 managed to stumble upon this write up