In the past year or so cellphone jamming has become an increasingly more popular subject. Everyone has been plagued by obnoxious cellphone users in malls, buses, school, work, movie theaters, and in spite of being highly illegal, cellphone jammers are popping up in more and more places. Green Bay Professional Packet Radio has a great writeup on how it works and even a how-to for building your own
Afroman’s digital capacitor writeup is mostly theory, but it has some good applications and looks like it could be pretty useful for future projects “By manipulating the input/output states on a microcontroller, you can effectively switch capacitors in and out of circuit, as long as the circuit requires one end of the capacitor to be connected to ground when it is in use. When you set a PIC’s tristate buffer
If you’ve ever tried to couple a cheap mp3 player with good headphones, you know much of a pain it can be. This is a walk-through of how to build your own. “Chu Moy designed a very popular headphone amplifier that’s easy to build, and it can be built small enough to fit in a pocket, power supply and all. It’s powerful enough to drive very inefficient headphones to thunderous
