Recreating Ben Franklins kite experiment with a drone

Drone Replaces Kite In Recreation Of Famous Atmospheric Electricity Experiment

Finally, someone decided to answer the question that nobody was asking: what if [Benjamin Franklin] had had a drone rather than a kite?

Granted, [Jay Bowles] didn’t fly his electricity-harvesting drone during a thunderstorm, but he did manage to reach some of the same conclusions that [Dr. Franklin] did about the nature of atmospheric electricity. His experimental setup was pretty simple: a DJI Mini2 drone with enough payload capacity to haul a length of fine-gauge magnet wire up to around 100 meters above ground level. A collecting electrode made of metal mesh was connected to the wire and suspended below the drone. Some big nails were driven into the soil to complete the circuit between the drone and the ground.

[Jay] went old-school for a detector, using a homemade electroscope to show what kind of static charge was accumulating on the electrode. Version 1 didn’t have enough oomph to do much but deliver a small static shock, but a larger electrode was able to deflect the leaves of an electroscope, power a beer can version of a Franklin bell, and also run a homemade corona motor. [ElectroBOOM] makes a guest appearance in the video below to explain the physics of the setup; curiously, he actually managed to get away without any injuries this time. Continue reading “Drone Replaces Kite In Recreation Of Famous Atmospheric Electricity Experiment”

Into The Plasmaverse Hack Chat

Join us on Wednesday, September 23 at noon Pacific for the Into the Plasmaverse Hack Chat with Jay Bowles!

Most kids catch on to the fact that matter can exist in three states — solid, liquid, and gas — pretty early in life, usually after playing in the snow a few times. The ice and snowflakes, the wet socks, and the fog of water vapor in breath condensing back into water droplets all provide a quick and lasting lesson in not only the states of matter but the transitions between them. So it usually comes as some surprise later when they learn of another and perhaps more interesting state: plasma.

For the young scientist, plasma is not quite so easy to come by as the other phases of matter, coming about as it does from things they’re usually not allowed to muck with. High voltage discharges, strong electromagnetic fields, or simply a lot of heat can strip away electrons from a gas and make the ionized soup that we call plasma. But once they catch the bug, few things can compare to the dancing, frenetic energy of a good plasma discharge.

Jay Bowles picked up the plasma habit quite a while back and built his YouTube channel around it. Tesla coils, Van de Graaff generators, coils and capacitors of all types — whatever it takes to make a spark, Jay has probably made and used it to make the fourth state of matter. He’ll join us on the Hack Chat to talk about all the fun things to do with plasma, high-voltage discharge, and whatever else sparks his interest.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, September 23 at 12:00 PM Pacific time. If time zones baffle you as much as us, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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A Dangerous Demonstration Of The Power Of Radio

Terrestrial radio may be a dying medium, but there are still plenty of listeners out there. What would a commute to or from work be without a check of “Traffic on the Eights” to see if you need to alter your route, or an update of the scores from yesterday’s games? Getting that signal out to as many listeners as possible takes a lot of power, and this dangerous yet fascinating demo shows just how much power there is on some radio towers.

Coming to us by way of a reddit post, the short video clips show a crew working on a 15,000-Watt AM radio tower. They appear to be preparing to do tower maintenance, which means de-energizing the antenna. As the engineer explains, antennas for AM radio stations in the medium-wave band are generally the entire tower structure, as opposed to the towers for FM and TV stations, which generally just loft the antenna as high as possible above the landscape. The fun starts when the crew disconnects a jumper and an arc forms across the clamp and the antenna feed. The resulting ball of plasma acts like a speaker, letting us clearly hear the programming on the station. It’s like one of the plasma speakers we’ve seen before, albeit exceptionally more dangerous.

It’s an impressive display of the power coursing through broadcast towers, and a vivid reminder to not mess with them. Such warnings often go unheeded, sadly, with the young and foolish paying the price. There’s a reason they put fences up around radio towers, after all.

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Solar Panel Keeps Car Battery Topped Off Through OBD-II Port

Up until the 1980s or so, a mechanic could check for shorts in a car’s electrical system by looking for sparks while removing the battery terminal with everything turned off in the car. That stopped being possible when cars started getting always-on devices, and as [Kerry Wong] learned, these phantom loads can leave one stranded with a dead battery at the airport after returning from a long trip.

[Kerry]’s solution is simple: a solar trickle charger. Such devices are readily available commercially, of course, and generally consist of a small photovoltaic array that sits on the dashboard and a plug for the lighter socket. But as [Kerry] points out in the video below, most newer model cars no longer have lighter sockets that are wired to work without the ignition being on. So he chose to connect his solar panel directly to the OBD-II port, the spec for which calls for an always-on, fused circuit connected directly to the positive terminal of the vehicle battery. He had to hack together an adapter for the panel’s lighter plug, the insides of which are more than a little scary, and for good measure, he added a Schottky diode to prevent battery discharge through the panel. Even the weak winter sun provides 150 mA or so of trickle charge, and [Kerry] can rest assured his ride will be ready at the end of his trip.

We used to seeing [Kerry] tear down test gear and analyze unusual devices, along with the odd post mortem on nearly catastrophic failures. We’re glad nothing burst into flames with this one.

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Mr. Carlson Gets Zapped By Snow

As a Canadian, [Mr. Carlson] knows a thing or two about extreme winter weather. Chances are good, though, that he never thought he’d get zapped with high voltage generated by falling snow.

[Mr. Carlson]’s shocking tale began with a quiet evening in his jam-packed lab as a snowstorm raged outside. He heard a rhythmic clicking coming from the speakers of his computer, even with the power off. Other speakers in the lab were getting into the act, as was an old radio receiver he had on the bench. The radio, which was connected to an outdoor antenna by a piece of coax, was arcing from a coil to the chassis in the front end of the radio. The voltage was enough to create arcs a couple of millimeters long and bright blue-white, with enough current to give [Mr. Carlson] a good bite when he touched the coax. The discharges were also sufficient to destroy an LED light bulb in a lamp that was powered off but whose power cord was unlucky enough to cross the antenna feedline.

Strangely, the coil from which the arc sprang formed a 36-ohm shunt to the radio’s chassis, giving the current an apparently easy path to ground. But it somehow found a way around that, and still managed to do no damage to the sturdy old radio in the process. [Mr. Carlson] doesn’t offer much speculation as to the cause of the phenomenon, but the triboelectric effect seems a likely suspect. Whatever it is, he has set a trap for it, to capture better footage and take measurements should it happen again. And since it’s the Great White North, chances are good we’ll see a follow-up sometime soon.

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This Lightning Detector Is Remarkably Sensitive

Lightning strikes are quite high energy events, and release plenty of radio frequency energy when they go off in the atmosphere. This makes them easy to detect, and the magnitude of the energy release means it can be done at impressive range. [Jay] decided to build a device of his very own, and was impressed at its detection performance.

The device is a simple but effective design. An antenna is used to capture RF signals, and these are then amplified through a single transistor stage. This is connected to a basic transistor flasher circuit, which is biased to only flash when tipped over the edge by an incoming signal. After building the circuit, [Jay] noticed that the device wasn’t just picking up signals from lightning, but also those from many other smaller discharges. The device was able to detect a shock from wearing socks on a wood floor, as well as discharges from a Van de Graff generator and even just from getting out of a chair!

Lightning detectors have been around for a long time now; we’ve seen others grace these pages before. Video after the break.

Continue reading “This Lightning Detector Is Remarkably Sensitive”

Homebrew Battery Discharger

Rechargable batteries are great – they save money and hassle when using portable devices. It’s pretty common to want to recharge a battery, but less common to intentionally discharge one. Regardless, [Pawel Spychalski] is working on a device to do just that – in a controlled fashion, of course.

[Pawel] himself notes that the device isn’t something the average person would necessarily need, but it does have its applications. There are times when working with various battery chemistries that it is desired to have them held at a certain state of charge. Also, such devices can be used to measure the capacity of batteries by timing how long they take to discharge when placed under a given load.

The build is one that takes advantage of the available parts of the modern hacker’s junkbox. An Arduino is used with an N-channel MOSFET to switch a resistive load. That load consists of load resistors designed for automotive use, to allow cars originally designed for filament bulbs to use LED indicator lights without the flash frequency speeding up. The resistors are 10 ohms and rated at 50 W, so they’re just about right for ganging up to discharge small LiPo batteries in a short period of time.

[Pawel] has tested the basic concept, and has things working. Next on the agenda is to find a way to get rid of the excess heat, as the current design has the resistors reaching temperatures of 158 °F (70 °C) in just a few minutes. Use some of that power to drive a fan?

Perhaps you’re working with lead acid batteries, though – in which chase, you might want to consider blasting away the sulphates?