One practical use of large switches and indicator lamps is to make a power distribution panel which can be useful when you want to control and monitor the power consumption of numerous devices such as your electronics work bench or amateur radio station. Old-school in appearance and using military surplus electronics, this power distribution panel allows for control of outlet on back. Did I mention I built it when I was 16?
Building it was easy, 120 VAC line enters through a main breaker. It is fed through an AC amp meter (with built-in shunt) then to a line filter. From the line filter it goes to a line voltage meter and filament transformer to power the indicator lamps. This AC line is then bussed out to the circuit breakers. Each breaker controls one outlet on the rear panel. As devices are switched on or off the current draw can be measured. This is well demonstrated in the video overview found after the break.
Be creative. Use military surplus switches, indicators, and other unique looking hardware. Customize to give your preferred mad scientist look while also providing valuable functionality.
Yes much of this material is very dated; CB Radios, all-mighty computers, phasors, stun guns, levitating machines, overly complex circuits for simple tasks, and aviator eyeglasses. But found among all of this, many innovative mixed-signal circuits and other interesting ideas that have been developed into our tech-centric world. Many of those modern inventions you’ve welcomed into your life actually started long-long ago in the forward-thinking hacks shown off in these publications. The Google Glass precursor seen above is but one example. Keep reading to see the early roots of the tech we tend to think of as “new”.
We capped off day-2 of the Hamvention with an unexpected rain shower, and some arcing back in the hotel room. Historically, Saturday is the best attended day of the show. As normally, we spent most of the day outside in the flea market. One of our friends allowed us to use his AN/GRC-9 army surplus radio to check into one of the nets. The radio was powered by hand-crank. Later, we attended a forum on the construction of HF antennas for camping trips, and obtained parts for our project back in the room. More about that later? Overall, a great day.
For one weekend in May, the landscape of Dayton, Ohio is dominated by ham radio operators. The Dayton Hamvention (“ham-convention”), sponsored by the Dayton Amateur Radio Association, is the preeminent gathering of hams from around the world. This is where industry rolls out new products, friends gather to catch-up, and old equipment is “re-distributed” amongst willing parties in the sprawling swap meet which subsumes the entire Hara Arena parking lot where you can find almost anything and meet some of the most interesting people.
Lunar dune buggy rides, piloting the most powerful machine made by humankind, stuck thrusters, landing, eating, sleeping, and working on the moon. It does not get any more exciting than the Apollo program! I was recently given the opportunity to sit in on the MIT course, Engineering Apollo: the Moon Project as a Complex System where I met David Scott who landed on the moon as commander of Apollo 15. I not only sat in on a long Q and A session I also was able to spend time with David after class. It is not every day you that you meet someone who has landed on the moon, below are my notes from this experience.
This year Scott Pastor (KC8KBK) and I will be covering Hamvention for Hackaday. We plan to provide one update after each day of Hamvention summarizing the day’s events. We hope to see you in Dayton next week!
Until recently phased array radar has been very expensive, used only for military applications where the cost of survival weighs in the balance. With the advent of low-cost microwave devices and unconventional architecture phased array radar is now within the reach of the hobbyist and consumer electronics developer. In this post we will review the basics of phased-array radar and show examples of how to make low-cost short-range phased array radar systems — I built the one seen here in my garage! Sense more with more elements by making phase array your next radar project.
Phased array radar
In a previous post the basics of radar were described where a typical radar system is made up of a large parabolic antenna that rotates. The microwave beam projected by this antenna is swept over the horizon as it rotates. Scattered pulses from targets are displayed on a polar display known as a Plan Position Indicator (PPI).
In a phased array radar (PDF) system an array of antenna elements are used instead of the dish. These elements are phase-coherent, meaning they are all phase-referenced to the same transmitter and receiver. Each element is wired in series with a phase shifter that can be adjusted arbitrarily by the radar’s control system. A beam of microwave energy is focused by applying a phase rotation to each phase shifter. This beam can be directed anywhere within the array’s field of view. To scan the beam rotate the phases of the phase shifters accordingly. Like the rotating parabolic dish, a phased array can scan the horizon but without the use of moving parts.