The Little Mechanism That Made Precise Time-keeping Possible

There are few things to which we pay as much attention as the passage of time. We don’t want to be late for work, or a date. Even more importantly, we don’t want to age and die. Good time keeping is an all important human activity, and we started to worry about it as soon as we abandoned our hunter-gatherer lifestyle and agriculture and commerce emerged.

By de:Benutzer:Flyout - own work, http://de.wikipedia.org/wiki/Bild:Kerzenuhr.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1783765
A candle clock

Measuring time needs two things: a repetitive process to mark equal increments of time, and a way of tracking and displaying the result. The first timekeeping devices relied of course on the movement of the sun. Ancient Egyptians, around 3500 BC, built obelisks that, by casting a shadow on the ground at different positions, gave an approximate idea of the time. Next came the use of some medium that was consumed at a regular pace: candle, incense, water and sand clocks are examples. A great advancement came with the advent of the mechanical clock, and here is where the escapement mechanism appears.

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Ikea Desk Lamp That Will Defend Your Lungs

While some people may enjoy the occasional whiff of noxious smells — gasoline, axe body spray, etc — prolonged exposure to fumes is not good for your health. This goes for soldering too, isn’t it about time you added some abatement to your bench tools?

Inspired by some of the fume hoods we’ve featured before — take note, ye who art lacking projects — [Georg Sluyterman] put together his own Ikea lamp fume extractor.

The most striking feature is that it’s mounted on an Ikea desk lamp making for convenient positioning and minimal clutter. A NeoPixels strip lights up your soldering space while the PIR sensor activates the fan when it detects movement. A WeMos D1 Mini is included for WiFi connectivity but that feature still down the road a little bit. The functionality that is in place is still quite impressive; more on that after the break.

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Make Water Bridges With High Voltages

It’s generally a bad idea to mix high voltage electricity and water, but interesting things happen if you do. This video from [RWGResearch] shows one of them: water bridging. If you have two water sources (such as two beakers full of very highly distilled water) with a high voltage between them, the voltage can create a gravity defying bridge that flows between them.

The experiment starts with the pouring spouts from two beakers nearly touching each other. Water fills the beakers right up to the spout, but it’s the application of electricity that pulls the bridge between the positive and negative beakers. With care, this technique can create a bridge of up to 2cm (about 0.8 inches). [RWGResearch] shows that he is able to create a bridge of about a centimeter with a 5KV voltage, but which only carries a few milliamps.

What forces are at play here isn’t exactly clear, but one recent paper speculates that it’s down to a combination of the dielectric force caused by the differing charges of parts of water molecules and the surface tension of the water. Whatever it is, it is fascinating and makes for a neat trick.

Want to make your own contribution to the scientific body of knowledge? Prove or disprove the speculation mentioned in the Wikipeadia article: is this possible because of an H3O2 lattice formed by the high voltage? How would you formulate a test for this?

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Archaeology, Virtually.

Drone technology is seeing useful application in a new field seemingly every day — so it was only a matter of time before it saw use in archaeology. And so, a team of researches in Australia are combining drone and VR modeling technology to help investigate the Plain of Jars, in Laos.

After the drone images the site, those photos are patched together by object recognition software and are reviewed in the immersive CAVE2 3D facility at Melbourne, Australia’s Monash University. Multiple surveys catalog and archive the dig at various stages and enable the archaeologists to continue investigating the site after leaving — especially useful for digs in dangerous regions. In this case, the landscape around the Plain of Jars is dotted with unexploded cluster bomblets.

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Documentation? Wave Me!

A lot of hardware and software hackers aren’t all that keen on documentation. The problem is, if you don’t document, it is harder for people to replicate or build on your work. If you aren’t happy writing, keep the old adage in mind: a picture is worth a thousand words.

With a digital design, a timing diagram is often a key piece of documentation. WaveMe is a free Windows program that makes it easy to create good-looking timing diagrams. You can run the software on other platforms via Wine.

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Getting A Handle On ESR With A Couple Of DIY Meters

Got a bunch of questionable electrolytic caps sitting in your junk bin? Looking to recap a vintage radio chassis? Then you might need to measure the equivalent series resistance of the capacitors, in which case this simple five-transistor ESR meter might come in handy.

Even if you have no need for an ESR meter, [W2AEW]’s video below is a solid introduction to how ESR is determined. The circuit itself comes from EEVBlog forum user [Jay-Diddy_B] and is about as simple as such a circuit can get. Two transistors form an oscillator that generates a square wave that drives a resistor bridge network. The two legs of the bridge feed matched common-emitter amps, one leg through the device under test. The difference in voltage between the two legs is read on a meter, and you have a quick and simple way to sort through the caps in your junk bin. [Jay-Diddy_B]’s circuit is only presented in breadboard form; no attempt was made to field a practical instrument. Indeed, [W2AEW] already built a home-brew ESR meter using hex inverters and op amps to which he compares the five-transistor circuit’s results. His intention here seems to be to clarify the technique of ESR measurement and evaluate an even simpler circuit than his. We think he’s done a good job on both counts.

We’ve featured plenty of [WA2AEW]’s work before, like this Michigan Mity-Mite transmitter or his primer on oscilloscopes. We really like his laid back style and the way he makes complex topics easy to understand. Check them out.

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Power Wheels engine compartment

Power Wheels Rescued, Restored And Enhanced

It seems power wheels are like LEGO — they’re handed down from generation to generation.  [Nicolas] received his brand-new Peg-Perego Montana power wheels in 1997 as a Christmas present. After sitting in a barn for a decade, and even being involved in a flood, it was time to give it to his godchildren, though not without some restoration and added features. His webpages have a very good write-up, just shy of including schematics, but you’ll find an abbreviated version below.

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