It’s no secret that a great deal of Western civilization was informed by the ancient Greeks. They revolutionized mathematics and geometry, developing astronomy along the way. They built ornate statues, beautiful temples to the gods, and amphitheaters for live entertainment with astonishing acoustics. The influence of the ancient Greeks shaped almost every field of human knowledge, from the arts and architecture to politics, philosophy, science, and technology.
Like the Babylonians, the Greeks paid close attention to the night sky. Our nearest celestial neighbor, the Moon, was particularly important to them from a planning perspective. For instance, debts might be due on the new Moon. By heeding the Moon’s phases and taking note of eclipse cycles, they found that their harvests were more fruitful, and they had fewer incidents at sea.
As savvy and well-rounded as ancient Hellenistic culture appears to have been, it’s not unreasonable to imagine that the Greeks could have created some kind of computing machine to make their Moon-centered scheduling easier. Based on fragments from in a shipwreck that was discovered in 1900, it seems they did exactly this. Based on scientific dating of the coins and pottery found in the wreck and inscriptions on the bronze remnants, historians and scientists believe the Greeks created a mechanical computer capable of calculating the positions of the Sun and the Moon on any given day. This marvelous device is known as the Antikythera mechanism.
The mechanism was housed in a wooden box and controlled with a knob on one side. It is believed that the front of the box was a display made up of a set of concentric rings with graduations, and that each ring corresponded with one celestial body. Pointers attached perpendicularly to output gears moved around the rings as the knob was turned, showing the paths and positions of these celestial bodies over time. This Earth-centric planetarium also displayed the phase of the Moon as well as the positions of the five major planets known to the ancient Greeks—Mercury, Venus, Mars, Jupiter, and Saturn.
A lot of us take roads for granted, at least until they are icy or torn up by construction. The concept of creating fixed paths seems to be in our firmware. Finding the shortest distance to food or water and marking a trail to it from home base has always been its own reward.
Roads have come a long way from the simple paths beaten by man and beast. But the basic configuration of paved roads hasn’t changed all that much since the Roman empire. Whatever they’re made of, they need to be able to drain water and support heavy loads.
New issues arose as modes of transportation shifted in favor of the automobile. Road surfaces needed to provide friction against tires. But how did we get from the stone-paved roads of Rome to the asphalt and concrete roads of today?
This makeover didn’t end with hiding wires and locking out noobs, though. [Cameron] added a float switch that will disable the pump when the water level gets too low. This is a nice touch. Otherwise, machines like this one will try to brew when the tank is dry, and then the pump has to be primed once the tank is refilled. [Cameron] also replaced the buttons’ back-lighting bulbs with bright LEDs. A small LCD mounted on the front of the machine shows the boiler temperature and shot-pulling duration.
If you’ve add PID temperature control to your espresso machine but have done nothing to improve the steam wand, why not add a pressure gauge?
If your local surplus store is fresh out of supercapacitors but you’re just really in the mood to fire stuff at other stuff, check out [austiwawa]’s step-by-step guide to building a thermal cannon. It shoots whatever will fit into a 1/2″ copper pipe, propelled by cut-up matchheads and lit by a propane torch. [austiwawa] demonstrates it by firing an AA battery at an unsuspecting pumpkin. For what it’s worth, we don’t necessarily condone applying this much heat to alkaline cells.
[austiwawa] used a copper pipe for the barrel because it provides the fastest heat transfer. One end of it is flattened and folded over to form the propellant chamber. A couple of packs worth of match heads are tamped down into the folded end with a paper towel serving as wadding. [austiwawa] tosses in his battery, lights the torch, and then runs away.
This whole dangerous contraption is secured to a wooden base with a u-bolt and a couple of pipe straps, and suspended between more pieces of wood with a length of threaded rod for stability and aiming.
We’ll let the safety-conscious readers do our work for us in the comments, but in the meantime, note that this thing is not safe. As [austiwawa] demonstrates, the copper gets brittle and will split open along the folded edge.
But kudos anyway to [austiwawa] for showing shot after shot of the cannon in action at the end of his video. You know where to find it.
As Cold War tensions increased throughout the 1970s, the Soviets pulled out all the stops when it came to digging up information from US diplomats. This NSA memo from 2012 explains how several IBM Selectric typewriters used in the Moscow and Leningrad offices were successfully bugged with electromechanical devices that could possibly have been the world’s first keyloggers.
The Selectric prints with a ball that is spun and tilted to select the desired character. Two mechanical arms control the ball’s spin and tilt, and the keylogger read out the position of those arms. Thus, each character on the Selectric’s type element ball has its own signature. The sensing part of the keylogging mechanism was buried in part of the typewriter chassis, a metal bar that spans the width of the machine, and were so well hidden that they could only have been detected by complete dissassembly or x-ray.
Horse racing has been around since the time of the ancient Greeks. Often called the sport of kings, it was an early platform for making friendly wagers. Over time, private bets among friends gave way to bookmaking, and the odds of winning skewed in favor of a new concept called the “house”.
During the late 1860s, an entrepreneur in Paris named Joseph Oller invented a new form of betting he called pari-mutuel. In this method, bettors wager among themselves instead of against the house. Bets are pooled together and the winnings divided among the bettors. Pari-mutuel betting creates more organic odds than ones given by a profit-driven bookmaker.
Oller’s method caught on quite well. It brought fairness and transparency to betting, which made it even more attractive. It takes a lot of quick calculations to show real-time bet totals and changing odds, and human adding machines presented a bottleneck. In the early 1900s, a man named George Julius would change pari-mutuel technology forever by making an automatic vote-counting machine in his garage.
Planning to make that carved a pumpkin last past Halloween night? Forget the tealight or LED candle—here’s an easy, no-solder project that will make it extra special. By default, this jack-o-lantern looks like it has a flickering flame, but get close enough to it and it goes crazy with color.
All you need is an LED matrix, a Rainbowduino to drive it, a PIR motion sensor to trigger the random colors, and a power source. [Alpha Charlie] kept the electronics from becoming pumpkin-flavored with some plastic bags. Since he used the PIR as the jack-o-lantern’s nose, there is a bit of plastic behind it to keep moisture from interfering.
[Alpha Charlie]’s build instructions are quite detailed, which makes this project even simpler if you’ve never used a PIR before. There are lots of ways you could build on this project to make it your own, like using trick-or-treater motion to trigger screams or spooky sounds, or add more sensors to make it more interactive. Watch it react after the break.