A series of trapezoidal steel "buckets" attached together to form a metal water wheel. They are arranged around a square center frame that attaches to a hub for the wheel to spin about. The wheel is next to a stream and four people of various ages appear to be talking around it. A cinder block building with a metal roof is in the left background, and an older, yellow stone building is far off in the distance on the right of the image. The landscape is lush, green, and mountainous.

Open Source Waterwheel

Here in the West, power going out is an unusual event. But in more remote regions like the Himalayas, reliable electricity isn’t a given. A group of local craftspeople, researchers, and operators in Nepal have worked together to devise a modular waterwheel system.

Based on a 20-30 cm-wide bucket module consisting of only four galvanized steel components, the wheels can be easily built and deployed using resources and tools that are easy to find anywhere in the world. Current test devices generate between 120 and 1,400 Watts of power, depending on the device’s size.

A software tool was also developed that takes the head and flow rate of a location as inputs to calculate the dimensions of the optimal wheel and expected power output for an installation. This lets communities find ideal sites for power generation and calculate the expected costs.

We’ve covered a few other DIY hydropower setups, from repurposed washing machines to custom scratch builds.

Is This The World’s Largest Dot Matrix Printer?

[RyderCalmDown] was watching a road painting vehicle lay down fresh stripes on the road one day and started thinking about the mechanism that lets it paint stripes in such a precise way. Effectively the system that paints the interspersed lines acts as a dot matrix printer that can only print at a single frequency. With enough of these systems on the same vehicle, and a little bit more fine control of when the solenoids activate and deactivate, [RyderCalmDown] decided to build this device on the back of his truck which can paint words on a roadway as he drives by. (Video, embedded below.)

Of course, he’s not using actual paint for this one; that might be prohibitively expensive and likely violate a few laws. Instead he’s using a water-based system which only leaves temporary lettering on the pavement. To accomplish this he’s rigged up a series of solenoids attached to a hitch-mounted cargo rack. A pump delivers water to each of the solenoids, and a series of relays wired to a Raspberry Pi controls the precise timing needed to make sure the device can print readable letters in much the same way a dot matrix printer works. There’s an algorithm running that converts the inputted text to the pattern needed for the dot matrix, and after a little bit of troubleshooting it’s ready for print.

Even though the printer works fairly well, [RyderCalmDown] had a problem thinking of things to write out on the roadways using this system, but it’s an impressive build based around a unique idea nonetheless. Dot matrix printers, despite being mostly obsolete, have a somewhat vintage aesthetic that plenty of people still find desirable and recreate them in plenty of other ways as well, like this 3D printer that was modified to produce dot matrix artwork.

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Weird Electric Jet Skis Are Hitting The Waves

When it comes to reducing emissions from human sources, we’re at the point now where we need to take a broad-based approach. It’s not enough to simply make our cars more efficient, or start using cleaner power plants. We need to hit carbon zero, and thus everything has to change.

To that end, even recreational watercraft are going electric in this day and age. Several companies are developing motor-powered models that deliver all the fun without the emissions. But to do that, they’re taking to the air.

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Remote Water Quality Monitoring

While it can be straightforward to distill water to high purity, this is rarely the best method for producing water for useful purposes. Even drinking water typically needs certain minerals in it, plants may need a certain pH, and wastewater systems have a whole host of other qualities that need to be measured. Measuring water quality is a surprisingly complex endeavor as a result and often involves a wide array of sensors, much like this water quality meter from [RowlesGroupResearch].

The water quality meters that they are putting to use are typically set up in remote locations, without power, and are targeting natural bodies of water and also wastewater treatment plants. Temperature and pH are simple enough to measure and grasp, but this device also includes sensors for total dissolved solids (TDS) and turbidity which are both methods for measuring various amounts and types of particles suspended in the water. The build is based around an Arduino so that it is easy for others to replicate, and is housed in a waterproof box with a large battery, and includes data logging to an SD card in order to make it easy to deploy in remote, outdoor settings and to gather the data at a later time.

The build log for this device also goes into detail about all of the steps needed to set this up from scratch, as well as a comprehensive bill of materials. This could be useful in plenty of professional settings such as community wastewater treatment facilities but also in situations where it’s believed that industrial activity may be impacting a natural body of water. For a water quality meter more focused on drinking water, though, we’d recommend this build that is trained on its own neural network.

Pi Pico Calculates Water Usage

Modern WiFi-enabled microcontrollers have made it affordable and easy to monitor everything from local weather information to electricity usage with typically no more than a few dollars worth of hardware and a little bit of programming knowledge. Monitoring one’s own utility data can be a little bit more difficult without interfering with the metering equipment, but we have seen some clever ways of doing this over the years. The latest is this water meter monitoring device based on a Raspberry Pi Pico.

The clever thing here isn’t so much that it’s based on the tiniest of Raspberry Pis, but how it keeps track of the somewhat obscured water flow information coming from the meter. Using a magnetometer placed close to the meter, the device can sense the magnetic field created as water flows through the meter’s internal sensors. The magnetic field changes in a non-obvious way as water flows through it, so the program has to watch for specific peaks in the magnetic field. Each of these specific waveforms the magnetometer detects counts to 0.0657 liters of water, which is accurate for most purposes.

For interfacing with a utility meter, this is one of the more efficient and elegant hacks we’ve seen in a while. There have, of course, been other attempts to literally read the meter using web cams and computer vision software, but the configuration for these builds is much more complex than something like this. You can interface with plenty of utility meters other than water meters, too, regardless of age.

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Hackaday Links: December 4, 2022

Well, this is embarrassing! Imagine sending a multibillion-dollar rover to an ancient lakebed on Mars only to discover after a year of poking around at the rocks that it might not actually have been a lake after all. That seems to be the impression of Jezero Crater that planetary scientists are forming after looking at the data coming back from Perseverance since it nailed the landing in what sure as heck looked like a dried-up lake, complete with a river delta system. A closer look at the sediments Perseverance has been sampling reveals a lot of the mineral olivine, which on Earth is rare near the surface because it readily reacts with water. Finding lots of olivine close below the surface of Jezero suggests that it either wasn’t all that watery once upon a time, or that what water was there was basically ice cold. The results are limited to where the rover has visited, of course, and the nice thing about having wheels is that you can go somewhere else. But if you were hoping for clear signs that Jezero was once a lake teeming with life, you might have to keep waiting.

In other space news, we have to admit to taking NASA to task a bit in the podcast a couple of weeks back for not being quite up to SpaceX’s zazzle standards with regard to instrumenting the SLS launch. Yeah, a night launch is spectacular, but not having all those internal cameras like the Falcon has just sort of left us flat. But we should have been more patient, because the images coming back from Artemis 1 are simply spectacular. We had no idea that NASA attached cameras to the solar panels of the Orion spacecraft, which act a little like selfie sticks and allow the spacecraft to be in the foreground with Earth and the Moon in the background. Seeing Earth from lunar distance again for the first time in 50 years has been a real treat, and getting our satellite in the frame at the same time is a huge bonus.

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A two picture montage with the left montage showing a pair of hands holding an assembled and closed turbidity sensor and the right picture showing A pair of hands holding the screw on cap for the turbidity sensor and a prototype board against a backdrop of green leave

Rapid Prototyping To Measure Turbidity In Rapids

[RiverTechJess] is in the process of getting a PhD in environmental engineering and has devoted a chapter to creating a turbidity sensor for river network monitoring. Environmental sensing benefits from being able to measure accurately and frequently, so providing low cost devices helps get more data and excuse the occasional device loss that’s bound to happen when deploying electronics out in the wild. Towards this end, [RiverTechJess] has created a low cost turbidity sensor that rivals the more expensive alternatives in cost and accuracy.

The turbidity sensor is designed to be at least partially submerged allowing for the LED and light sensors to be be able to take measurements. [RiverTechJess] has made a 3D printed prototype to test the design, allowing for rapid experimentation and deployment of the sensors to work out issues. The 3D printed enclosure prototype uses rubber o-rings and “vacuum grease” to provide a watertight seal. An ESP32 microcontroller is used to store logged data on an SD card and drive the TSHG6200 850nm infrared LED and the two TSL237S-LF sensors.

The resulting paper on the turbidity sensor, in addition to the blogs of the process, provide a wealth of data that show what goes into developing and calibrating a device that is meant to be used for environmental monitoring. All source code is available on GitHub and development continues on a newer revision of the turbidity sensor with updated electronics and hardware.

We’re no strangers to water sensors and we’ve seen devices from internet connected water pollution monitors to small handheld potable water detectors.

Video after the break!

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