On this installment of Retrotechtacular we’re taking a look at the history of the United States Antiballistic Missile System. The cold war was a huge driver of technological development, and this missile defense is a good example. At its most basic this is a radar system capable of tracking objects in three dimensions. It utilizes separate transmitters and receivers which are synchronized to rotate at the same time.
The movie, which is about forty-five minutes, came to our attention because of [Dammitd’s] interest in the Luneburg Lens used by the system. At about 11:10 into the video after the break this component is discussed. Inside a dome like the one seen above is a reflector made of blocks of polystyrene foam which has been laced with bits of metal. This lens is stationary, with the receiver rotating around it to collect the transmitter’s waves as the echos bouncing off an object in the sky are focused by the lens.
It’s possible that it was [Matt Meerian]’s awesome pun that won us over, not his ultrasonic bicycle dog defense system, but that would be silly. [Matt] wanted an elegant solution to a common problem when riding a bicycle, dogs. While, obscenities, ammonia, water, pepper spray, and others were suggested, they all had cons that just didn’t appeal to [Matt]. He liked the idea of using C02 powered high pressure sound waves to chase the dogs away with, but decided to choose a more electronic approach. He used a Atmel ATmega644 as the MCU, four 25kHz transmitters, and two 40kHz transmitters. When the rider sees a dog he simply flips a switch and it activates the transducers (along with, cleverly, a human audible horn so he doesn’t have to look down to know it’s working). So far [Matt] has not had a dog chase him in order to test it’s efficacy, but his cat clearly seems unaffected by the device as you can see after the break. Continue reading “Defense Against the Dog Arts”→
Every reasonable person prepares for the future. Whether it’s matching your employer’s 401k contributions, making sure you have bread and milk before a snow storm, or saving for your kid’s college fund, planning for the future gives you a comfortable life. [Gord] has exceptional foresight; he build an awesome Louisville Decapitron for the upcoming zombie apocalypse.
It’s an urban legend that a bullet to the brain will stop a zombie. Instantaneous trepanation is devastating in the living, but we’re talking about the undead here. A melee weapon is what you’re after, and you’ve got to cut off the head. [Gord] based his project around a Louisville Slugger. The blade is a 20 inch long piece of plasma cut mild steel. It’s just a prototype to get the balance figured out; the final version will be done in carbon steel.
The tang of the blade fits into two notches in the bat. The blade is secured with two custom fabricated spacers that are perpendicular to the blade. We’re not quite sure of the nomenclature of the resulting weapon (it’s some type of battle axe, we’re sure), but we couldn’t think of a better way to decapitate the undead.
As builders of improvised electronic devices, we’re worried that we may find ourselves running afoul of the law. Lucky for us, we’ve got the advice of Regent University Law Professor James Duane on using the 5th amendment. He runs through many examples where saying anything at all, truth or otherwise, can get you into trouble. Embedded below is the other side: Officer George Bruch discussing some of the interview techniques he uses.