DIY Home Theater Preamplifier


[Dane] built this excellent home theater pre-amplifier. He used [Mark Hennesy]‘s pre-amp design to start with, and added selectable XLR, RCA, SPDIF and even USB audio inputs. Discrete inputs from his DVD player provide surround input, and an analog matrix creates 7.1 surround from the 5.1 input. The design is very elegant, and even uses a VFD display that appears blue with some filters. I usually just buy my HT gear, but projects like this make me seriously consider re-building my entire HT from scratch.

24C3 Build your own UAV


The 24th annual Chaos Communications Congress in Berlin is already off to a great start. The first talk we attended was [Antoine Drouin] and [Martin Müller] presenting Paparazzi – The Free Autopilot. Paparazzi is an open source hardware and software project for building autonomous unmanned aerial vehicles. The main hardware board has an ARM processor and GPS. It uses inertial and infrared sensors to determine orientation and altitude. The four infrared thermopiles measure the air temperature. The ground is warmer than the sky and if you compare the temperature in the direction of each wing tip your can tell what angle the airplane is at. It’s really that simple.

They did a pretty amazing live demo. Using the network connection they controlled a UAV flying in France and another in Germany. Both planes were streaming live video from belly mounted cameras. One relaying through a home DSL connection and the other through a UMTS cellphone. They were able to change way-points on the fly and issue flight pattern commands. There is a ground crew at each location with a security pilot that will switch the controls to manual if things get out of hand.