Quint explaining his water turbine

Power Your Home With A Water Battery

I’ve stated it before on Hackaday but one of the most interesting engineering challenges posed to me this year was “how could you store enough energy to power a decent portion of a home for several hours without using batteries, all while staying within the size of a typical suburban plot?” [Quint Builds] attempts something up that alley by using solar power to pump water up onto his roof and later releasing it for power generation. (Video, embedded below.)

Earlier [Quint] had built a water collecting system using his gutters and a bell siphon but wasn’t satisfied with the overall power output. Using the turbine he had created for that system, he put a 55-gallon drum on top of his roof with the help of some supporting structures. We’d like to advise the public to consult a professional before adding a large heavy weight on top of your roof, but [Quint] forges ahead after studying his trusses and determining it to be a risk he is willing to take. A solar panel runs a small pump that pumps water from a reservoir up to the top of the roof when the sun shines with a float switch in the roof barrel stopping the motor once it’s full. A valve at the bottom allows water to spin the turbine and fill back into the bottom reservoir, forming a closed loop. There were a few snags along the way with prototype circuits not being fully contacted and the motor needing water cooling, an issue fixed by a custom CNC’d heat sink. The fixes for the various issues are almost as entertaining to see as the actual system itself.

It’s incredible to see lights come on powered by water alone but also sobering to realize just how much water you’d need to power a typical home. Perhaps if [Quint] upgrades, he can swap out the small motor for a larger 3D printed water pump.

Continue reading “Power Your Home With A Water Battery”

Lord Kelvin’s Contraption Turns Drips Into Sparks

It’s easy to think that devices which generate thousands of volts of electricity must involve relatively modern technology, but the fact is, machines capable of firing sparks through open air predate Edison’s light bulb. Which means that recreating them with modern tools, construction techniques, and part availability, is probably a lot easier than most people realize. The fascinating machine [Jay Bowles] put together for his latest Plasma Channel video is a perfect example, as it’s capable of developing 6,000 volts without any electronic components.

Now as clever as [Jay] might be, he can’t take credit for the idea on this one. That honor goes to Lord Kelvin, who came up with this particular style of electrostatic generator back in 1867. Alternately called “Kelvin water dropper” or “Lord Kelvin’s Thunderstorm”, the machine is able to produce a high voltage charge from falling water without using any moving parts.

Diverging streams means a charge is building up.

Our very own [Steven Dufresne] wrote an in-depth look at how these devices operate, but the short version is that a negative and positive charge is built up in two sets of metallic inductor rings and buckets, with the stream of water itself acting as a sort of wire to carry the charge up to the overhead water reservoir. As [Jay] demonstrates the video, you’ll know things are working when the streams of water become attracted to the inductors they are passing through.

Rather than connecting a separate spark gap up to the water “receivers” on the bottom of his water dropper, [Jay] found the handles on the metal mugs he’s using worked just as well. By moving the mugs closer and farther away he can adjust the gap, and a second adjustment lets him move the vertical position of the inductors. It sounds like it takes some fiddling to get everything in position, but once it’s working, the whole thing is very impressive.

Of course if you’re looking to get serious with high voltage experiments, you’ll want to upgrade to some less whimsical equipment pretty quickly. Luckily, [Jay] has shown that putting together a reliable HV supply doesn’t need to be expensive or complicated.

Continue reading “Lord Kelvin’s Contraption Turns Drips Into Sparks”

Soil Moisture Sensors, How Do They Work?

In a way, the magic of a soil moisture sensor’s functionality boils down to a simple RC circuit. But of course, in practice there is a bit more to it than that. [rbaron] explains exactly how capacitive soil moisture sensors work simply, clearly, and concisely. He also shows, with a short video, exactly how their output changes in response to their environment, and explains how it informed his own sensor design.

At its heart, a moisture sensor measures how quickly (or slowly) a capacitor charges through a resistor, but in these sensors the capacitor is not a literal component, but is formed by two PCB traces that are near one another. Their capacitance — and therefore their charging rate — changes in response to how much water is around them. By measuring this effect on a probe sunk into dirt, the sensor can therefore indirectly measure the amount of water in the soil.

This ties into his own work on b-parasite: an open-source, all-in-one wireless soil moisture sensor (which was also a runner-up in our Earth Day contest) that broadcasts over BLE and even includes temperature readings. One thing to be mindful of if you are making your own PCBs or ordering them from a fab house is that passing current through metal in a moist environment is a recipe for oxidation, so it’s important not to expose bare traces to wet soil. A good coated PCB should avoid this problem, but one alternative we have seen proposed is to use graphite rods in place of metal.

Earth Day Challenge: A Better Way To Wrangle Water

How far do you have to go for a glass of clean water? Not very? Just go to a sink and turn on the faucet? We would venture to guess that is the case for most Hackaday readers. Maybe you even have a water softener, or a filter on your tap to make your drinking water even more palatable and free of heavy metal.

In Ethiopia and many other countries, people do not have access to clean, flowing water and must walk several kilometers to fetch it from somewhere that does. And they’re not doing this on paved roads, either — these women are cutting treacherous paths across mountains and through muddy, rocky terrain that make wheeled transport nearly impossible. How do you comfortably lug around 25 kg (~55 lbs) worth of sloshing water? You don’t, unless you have [Anteneh Gashaw]’s ingenious jerrycan.

As you can see in the video below, the current crop of jerrycans are just big plastic jugs that have to be carried on top of the head or the shoulder, both of which are bad for bodies. [Anteneh]’s can evenly distributes the weight by wrapping it completely around the person carrying it and suspending it from both shoulders like a beer-and-peanuts vendor’s carrying case. Basically, it’s a PVC inner tube with shoulder straps. Simple, cheap, and effective = absolute genius in our book. Ideally, everyone would have free access to clean water, both cold and hot. Until that time, [Anteneh]’s entry into our Earth Day Challenge is a great workaround that will no doubt save a lot of spines.

Potable water may be closer than you think. Build a portable potability predictor and you might not have to travel so far.

Continue reading “Earth Day Challenge: A Better Way To Wrangle Water”

Ask Hackaday: How Do You Prepare?

Last month, large parts of the southern United States experienced their coldest temperatures since the 1899 Blizzard. Some of us set new all-time lows, and I was right in the middle of the middle of it here in Southwestern Oklahoma. Since many houses in Texas and Oklahoma are heated with electricity, the power grids struggled to keep up with the demand. Cities in Oklahoma experienced some short-term rolling blackouts and large patches of the Texas grid were without power for several days. No juice, no heat.

In places where the power was out for an extended period of time, the water supply was potentially contaminated, and a boil order was in effect. Of course, this only works when the gas and power are on. In some places, the store shelves were empty, a result of panic buying combined with perishables spoiling without the power to keep them cold. For some, food and drinkable water was temporarily hard to come by.

There have been other problems, too. Houses in the south aren’t built for the extreme cold, and many have experienced frozen pipes, temporarily shutting off their water supply. In some cases, those frozen pipes break open, flooding the house once the water starts flowing again. For instance, here’s an eye-witness account of the carnage from The 8-bit Guy, who lives at ground zero in the DFW area.
Continue reading “Ask Hackaday: How Do You Prepare?”

Cyberattack On Florida City’s Water Supply

The city of Oldsmar, Florida was the source of disturbing news this week, among reports that someone gained unauthorized access to a water treatment facility. In an era where more systems than ever are connected to the Internet, the story is a sobering one for the vast majority of people reliant on grid utilties.

The hacker was first noticed to have gained remote access to a computer system at the plant at 8 a.m. on February 5. An operator at a workstation controlling chemical dosing at the plant observed a remote connection, though did not initially raise the alarm as such access is common practice at the facility for troubleshooting purposes. However, at 1:30 pm, the hacker connected again, this time commanding the dosing system to raise levels of sodium hydroxide in the water from 100 to 11,000 ppm – dangerous levels that would make the city’s water unsafe to drink. The increased level command was immediately overridden by the operator, who then raised the alarm.

The city notes that other safeguards such as pH monitors at the plant would have triggered in the event the original intrusion went undetected. However, the event raises renewed questions about the level of security around critical utility systems connected to the internet. In the last decade, cyberattacks on physical infrastructure have become a reality, not a vague future threat.

Nothing’s known yet about the perpetrator, or how secure the system was (or wasn’t?) before the event. It’s been long known that a lot of infrastructure is simply connected to the internet, as Dan Tentler has been showing us since at least 2012. (Video, ranting.)  Indeed, it’s amazing that we’ve seen so few malicious attacks.

Robust Water-Rocket Launcher Gets The Engineering Just Right

Normally when we run across a project that claims to be overengineered, we admit that we get a little excited. Such projects always hold the potential for entertainingly over-the-top designs, materials, and methods. In this case, though, we’ll respectfully disagree with [Zach Hipps] assessment of his remote-controlled soda bottle rocket launcher as “overengineered”. To us, it seems just right.

That’s not to take away from anything accomplished with this build. Indeed, we’re mighty impressed by the completeness of the build, which was intended to create a station for charging and launching air-powered water rockets. The process started with a prototype, built mainly from 3D-printed parts but with a fair selection of workshop scraps to hold it together. This allowed [Zach] to test the geometry of the parts, operation of the mechanism, and how it interfaced with the flange on the necks of 2-liter soda bottles.

Honestly, the prototype was pretty good by itself and is probably where many of us would have stopped, but [Zach] kept going. He turned most of the printed parts into machined aluminum and Delrin, making for a very robust pneumatically operated stand. We’ve got to say the force with which the jaws close around the bottle flange is a bit scary — looks like it could easily clip off a wayward finger. But if he manages to avoid that fate, such a hearty rig should keep [Zach] flying for a long time. Perhaps it could even launch a two-stage water rocket?

Continue reading “Robust Water-Rocket Launcher Gets The Engineering Just Right”