Author: Dan Maloney

3300 Articles

A LoRa Rain Gauge From The Ground Up

December 26, 2024 by 4 Comments

It’s a fair bet that most of us have a ton of wireless doo-dads around the house, from garage door remotes to wireless thermometers. Each of these gadgets seems to have its own idea about how to encode data and transmit it, all those dedicated receivers seem wasteful. Wouldn’t it be great to use existing RF infrastructure to connect your wireless stuff?

[Malte Pöggel] thinks so, and this LoRa rain gauge is the result. The build starts with a commercially available rain transmitter, easily found on the cheap as an accessory for a wireless weather station and already equipped with an ISM band transmitter. The rain-collection funnel and tipping-bucket mechanism were perfectly usable, and the space vacated by the existing circuit boards left plenty of room to play, not to mention a perfectly usable battery compartment. [Malte] used an ATmega328P microcontroller to count the tipping of the bucket, either through the original reed switch or via Hall Effect or magnetoresistive sensors. An RFM95W LoRa module takes care of connecting into [Malte]’s LoRaWAN gateway, and there’s an option to add a barometric pressure and temperature sensor, either by adding the BMP280 chip directly to the board or by adding a cheap I2C module, for those who don’t relish SMD soldering.

[Malte] put a lot of work into power optimization, and it shows. A pair of AA batteries should last at least three years, and the range is up to a kilometer—far more than the original ISM connection could have managed. Sure, this could have been accomplished with a LoRa module and some jumper wires, but this looks like a fantastic way to get your feet wet in LoRa design. You could even print your own tipping bucket collector and modify the electronics if you wanted.

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Hackaday Links: December 22, 2024

December 22, 2024 by 11 Comments

Early Monday morning, while many of us will be putting the finishing touches — or just beginning, ahem — on our Christmas preparations, solar scientists will hold their collective breath as they wait for word from the Parker Solar Probe’s record-setting passage through the sun’s atmosphere. The probe, which has been in a highly elliptical solar orbit since its 2018 launch, has been getting occasional gravitational nudges by close encounters with Venus. This has moved the perihelion ever closer to the sun’s surface, and on Monday morning it will make its closest approach yet, a mere 6.1 million kilometers from the roiling photosphere. That will put it inside the corona, the sun’s extremely energetic atmosphere, which we normally only see during total eclipses. Traveling at almost 700,000 kilometers per hour, it won’t be there very long, and it’ll be doing everything it needs to do autonomously since the high-energy plasma of the corona and the eight-light-minute distance makes remote control impossible. It’ll be a few days before communications are re-established and the data downloaded, which will make a nice present for the solar science community to unwrap.

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Hackaday Podcast Episode 301: Hacking NVMe Into Raspberry Pi, Lighting LEDs With Microwaves, And How To Keep Your Fingers

December 20, 2024 by 2 Comments

Twas the week before Christmas when Elliot and Dan sat down to unwrap a pre-holiday bundle of hacks. We kicked things off in a seasonally appropriate way with a PCB Christmas card that harvests power from your microwave or WiFi router, plus has the potential to be a spy tool. We learned how to grow big, beautiful crystals quickly, just in case you need some baubles for the tree or a nice pair of earrings. Speaking of last-minute gifts, perhaps you could build a packable dipole antenna, a very durable PCB motor, or a ridiculously bright Fibonacci simple add-on for your latest conference badge. We also looked into taking a shortcut to homebrew semiconductors via scanning electron microscopes, solved the mystery of early CD caddies, and discussed the sad state of table saw safety and the lamentable loss of fingers, or fractions thereof.

 

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Measuring A Well With Just A Hammer And A Smartphone

December 19, 2024 by 38 Comments

What’s the best way to measure the depth of a well using a smartphone? If you’re fed up with social media, you might kill two birds with one stone and drop the thing down the well and listen for the splash. But if you’re looking for a less intrusive — not to mention less expensive — method, you could also use your phone to get the depth acoustically.

This is a quick hack that [Practical Engineering Solutions] came up with to measure the distance to the surface of the water in a residential well, which we were skeptical would work with any precision due to its deceptive simplicity. All you need to do is start a sound recorder app and place the phone on the well cover. A few taps on the casing of the well with a hammer send sound impulses down the well; the reflections from the water show up in the recording, which can be analyzed in Audacity or some similar sound editing program. From there it’s easy to measure how long it took for the echo to return and calculate the distance to the water. In the video below, he was able to get within 3% of the physically measured depth — pretty impressive.

Of course, a few caveats apply. It’s important to use a dead-blow hammer to avoid ringing the steel well casing, which would muddle the return signal. You also might want to physically couple the phone to the well cap so it doesn’t bounce around too much; in the video it’s suggested a few bags filled with sand as ballast could be used to keep the phone in place. You also might get unwanted reflections from down-hole equipment such as the drop pipe or wires leading to the submersible pump.

Sources of error aside, this is a clever idea for a quick measurement that has the benefit of not needing to open the well. It’s also another clever use of Audacity to use sound to see the world around us in a different way.

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Homebrew Electron Beam Lithography With A Scanning Electron Microscope

December 19, 2024 by 7 Comments

If you want to build semiconductors at home, it seems like the best place to start might be to find a used scanning electron microscope on eBay. At least that’s how [Peter Bosch] kicked off his electron beam lithography project, and we have to say the results are pretty impressive.

Now, most of the DIY semiconductor efforts we’ve seen start with photolithography, where a pattern is optically projected onto a substrate coated with a photopolymer resist layer so that features can be etched into the surface using various chemical treatments. [Peter]’s method is similar, but with important differences. First, for a resist he chose poly-methyl methacrylate (PMMA), also known as acrylic, dissolved in anisole, an organic substance commonly used in the fragrance industry. The resist solution was spin-coated into a test substrate of aluminized Mylar before going into the chamber of the SEM.

As for the microscope itself, that required a few special modifications of its own. Rather than rastering the beam across his sample and using a pattern mask, [Peter] wanted to draw the pattern onto the resist-covered substrate directly. This required an external deflection modification to the SEM, which we’d love to hear more about. Also, the SEM didn’t support beam blanking, meaning the electron beam would be turned on even while moving across areas that weren’t to be exposed. To get around this, [Peter] slowed down the beam’s movements while exposing areas in the pattern, and sped it up while transitioning to the next feature. It’s a pretty clever hack, and after development and etching with a cocktail of acids, the results were pretty spectacular. Check it out in the video below.

It’s pretty clear that this is all preliminary work, and that there’s much more to come before [Peter] starts etching silicon. He says he’s currently working on a thermal evaporator to deposit thin films, which we’re keen to see. We’ve seen a few sputtering rigs for thin film deposition before, but there are chemical ways to do it, too.

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Simple Fluorometer Makes Nucleic Acid Detection Cheap And Easy

December 18, 2024 by 9 Comments

Back in the bad old days, dealing with DNA and RNA in a lab setting was often fraught with peril. Detection technologies were limited to radioisotopes and hideous chemicals like ethidium bromide, a cherry-red solution that was a fast track to cancer if accidentally ingested. It took time, patience, and plenty of training to use them, and even then, mistakes were commonplace.

Luckily, things have progressed a lot since then, and fluorescence detection of nucleic acids has become much more common. The trouble is that the instruments needed to quantify these signals are priced out of the range of those who could benefit most from them. That’s why [Will Anderson] et al. came up with DIYNAFLUOR, an open-source nucleic acid fluorometer that can be built on a budget. The chemical principles behind fluorometry are simple — certain fluorescent dyes have the property of emitting much more light when they are bound to DNA or RNA than when they’re unbound, and that light can be measured easily. DIYNAFLUOR uses 3D-printed parts to hold a sample tube in an optical chamber that has a UV LED for excitation of the sample and a TLS2591 digital light sensor to read the emitted light. Optical bandpass filters clean up the excitation and emission spectra, and an Arduino runs the show.

The DIYNAFLUOR team put a lot of effort into making sure their instrument can get into as many hands as possible. First is the low BOM cost of around $40, which alone will open a lot of opportunities. They’ve also concentrated on making assembly as easy as possible, with a solder-optional design and printed parts that assemble with simple fasteners. The obvious target demographic for DIYNAFLUOR is STEM students, but the group also wants to see this used in austere settings such as field research and environmental monitoring. There’s a preprint available that shows results with commercial fluorescence nucleic acid detection kits, as well as detailing homebrew reagents that can be made in even modestly equipped labs.

Catching The View From The Edge Of Space

December 18, 2024 by 26 Comments

Does “Pix or it didn’t happen” apply to traveling to the edge of space on a balloon-lofted solar observatory? Yes, it absolutely does.

The breathtaking views on this page come courtesy of IRIS-2, a compact imaging package that creators [Ramón García], [Miguel Angel Gomez], [David Mayo], and [Aitor Conde] recently decided to release as open source hardware. It rode to the edge of space aboard Sunrise III, a balloon-borne solar observatory designed to study solar magnetic fields and atmospheric plasma flows.

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