Hackaday Podcast 143: More Magnesium Please, Robot Bicep Curls, Malamud’s General Index, And Are You Down With EMC?

Hackaday editors Mike Szczys and Elliot Williams catch up on a week’s worth of hacks. Get a grip on robot hands: there’s an eerily human one on offer this week. If you’re doing buck/boost converter design, the real learning is in high-frequency design patterns that avoid turning your circuits into unintentional radiators. Those looking for new hobbies might want to take up autonomous boat racing. We saw a design that’s easy enough to print on the average 3D printer — and who doesn’t want to build their own jet boat? We’ll wrap up the episode by digging into magnesium sources, and by admiring the number of outfits who are rolling their own silicon these days.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (50 MB)

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Keep Calm And Hack On: The Philosophy Of Calm Technology

So much smart-tech is really kind of dumb. Gadgets intended to simplify our lives turn out to complicate them. It often takes too many “clicks” to accomplish simple tasks, and they end up demanding our attention. Our “better mousetraps” end up kludgy messes that are brittle instead of elegant and robust.

The answer might not be faster or newer technology, but a 30-year-old philosophy. Some great thinkers at Xerox PARC, the place where, among other things, the computer mouse was invented, developed principles they called Calm Technology.

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Photo of an arid desert landscape

How Practical Is Harvesting Water From The Air?

Water is one of the most precious substances required to sustain human life. Unfortunately, in some areas like California, it’s starting to run out.

The ongoing drought has some people looking towards alternative solutions, such as sucking water out of the very air itself. In particular, a company called Tsunami Products has been making waves in the press with its atmospheric water generators, touting them as a solution for troubled drought-stricken areas, as reported by AP News. Today, we’ll look at how these machine capture water, and whether or not they can help in areas short on water.

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A tiny bedside clock that's packed with features.

ESP32 Clock Takes Time To Give Weather Info, Too

It’s fall in the northern hemisphere, so [Mike Rankin]’s kids are back in school and have returned to consulting him every morning about the weather and what they should wear. Since he’s no meteorologist, [Mike] built a beautifully dim and diminutive clock that does all the work for him, plus much more. It glows a lovely dark orange that’s perfect for the nightstand and those early morning interrogations.

In default mode, this clock displays the time, CO2 level, room temperature, and humidity in that eye-friendly orange. But wave your hand in front of the time of flight sensor, and it goes external, displaying the low and high temperatures for the day, plus the weather conditions forecast. After a few seconds of that, it goes back to default mode. The ESP fetches the time from an NTP server, then gets the weather from the OpenWeather API. The indoor weather comes from a combination sensor on the board.

Diagram of the components on the circuit boardInside this tiny package is a beautifully-spun board with an ESP32 Pico D4 for a brain. In addition to the climate sensors there is a combination CO2/TVOC sensor (that’s total volatile organic compounds) to sniff out danger. There is also a pair of push buttons on the back and an ambient light sensor, but [Mike] isn’t using those just yet. Add in the Qwiic connector for future doo-dads, and you have quite the little gadget. Although the pictures make it look kind of big, you can see exactly how small it is in the demo video after the break.

[Mike] seems to like things tiny, and we admire that in a big way. Check out his positively Lilliputian ESP32 dev board.

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Snails, Sensors, And Smart Dust: The Michigan Micro Mote

If you want to track a snail, you need a tiny instrumentation package. How do you create an entire data acquisition system, including sensors, memory, data processing and a power supply, small enough to fit onto a snail’s shell?

Throughout history, humans have upset many ecosystems around the world by introducing invasive species. Australia’s rabbits are a famous example, but perhaps less well-known are the Giant African land snails (Lissachatina fulica) that were introduced to South Pacific islands in the mid-20th century. Originally intended as a food source (escargot africain, anyone?), they quickly turned out to be horrible pests, devouring local plants and agricultural crops alike.

Not to be deterred, biologists introduced another snail, hoping to kill off the African ones: the Rosy Wolfsnail (Euglandina rosea), native to the Southeastern United States. This predatory snail did not show great interest in the African intruders however, and instead went on to decimate the indigenous snail population, driving dozens of local species into extinction.

A snail with a solar sensor attached to its shell
A Rosy Wolfsnail carrying a light sensing Micro Mote on its back. Source: Cindy S. Bick et al., 2021

One that managed to survive the onslaught is a small white snail called Partula hyalina. Confined to the edges of the tropical forests of Tahiti, biologists hypothesized that it was able to avoid the predators by hiding in sunny places which were too bright for E. rosea. The milky-white shells of P. hyalina supposedly protected them from overheating by reflecting more sunlight than the wolf snails’ orange-brown ones.

This sounds reasonable, but biologists need proof. So a team from the University of Michigan set up an experiment to measure the amount of solar radiation experienced by both snail types. They attached tiny light sensors to the wolf snails’ shells and then released them again. The sensors measured the amount of sunlight seen by the animals and logged this information during a full day. The snails were then caught again and the data retrieved, and the results proved the original hypothesis.

So much for science, but exactly how did they pull this off? Continue reading “Snails, Sensors, And Smart Dust: The Michigan Micro Mote”

ClOCkTAL: For When Reading A Clock Is Just Too Easy

Over on Hackaday.io, [danjovic] presents clOCkTAL, a simple LED clock for those of us who struggle with the very concept of making it easy to read the time. Move aside binary clocks, you’re easy, let’s talk binary coded octal. Yes, it is a thing. We’ll leave it to [danjovic] to describe how to read the time from it:

Do not try to do the math using 6 bits. The trick to read this clock is to read every 3-bit digit in binary and multiply the MSBs by 8 before summing to the LSBs.

Simple. If you’re awake enough, that is. Anyway, we’re a big fan of the stripped-down raw build method using perf board, and scrap wood. No details hidden here. The circuit is straightforward, being based on a minimal configuration needed to drive the PIC16F688 and a handful of LEDs arranged in a 3×4 matrix.

An interesting detail is the use of Bresenham’s Algorithm to derive the one event-per-second needed to keep track of time. And no, this isn’t the more famous Bresenham’s line algorithm you may be more familiar with, it’s much simpler, but does work on the same principle of replacing expensive arithmetic division operations with incremental errors. The original Bresenham’s Algorithm was devised for using with X-Y plotters, which had limited resolution, and was intended to allow movements that were in an imperfect ratio to that resolution. It was developed into a method for approximating lines, then extended to cover circles, ellipses and other types of drawables.

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Highly Configurable Open Source Microscope Cooked Up In FreeCAD

What do you get when you cross a day job as a Medical Histopathologist with an interest in 3D printing and programming? You get a fully-baked Open Source microscope, specifically the Portable Upgradeable Modular Affordable (or PUMA), that’s what. And this is no toy microscope. By combining a sprinkle of off-the-shelf electronics available from pretty much anywhere, a pound or two of filament, and a dash of high quality optical parts, PUMA cooks up quite possibly one of the best open source microscopy experiences we’ve ever tasted.

GitHub user [TadPath] works as a medical pathologist and clearly knows a thing or two about what makes a great instrument, so it is a genuine joy for us to see this tasty project laid out in such a complete fashion. Many a time we’ve looked into an high-profile project, only to find a pile of STL files and some hard to source special parts. But not here. This is deliberately designed to be buildable by practically anyone with access to a 3D printer and an eBay account.

The project is not currently certified for medical diagnostics use, but that is likely only a matter of money and time. The value for education and research (especially in developing nations) cannot really be overstated.

A small selection of the fixed and active aperture choices

The modularity allows a wide range of configurations from simple ambient light illumination, with a single objective, great for using out in the field without electricity, right up to a trinocular setup with TFT-based spatial light modulator enabling advanced methods such as Schlieren phase contrast (which allows visualisation of fluid flow inside a live cell, for example) and a heads-up display for making measurements from the sample. Add into the mix that PUMA is specifically designed to be quickly and easily broken down in the field, that helps busy researchers on the go, out in the sticks.

The GitHub repo has all the details you could need to build your own configuration and appropriate add-ons, everything from CAD files (FreeCAD source, so you can remix it to your heart’s content) and a detailed Bill-of-Materials for sourcing parts.

We covered fluorescence microscopy before, as well as many many other microscope related stories over the years, because quite simply, microscopes are a very important topic. Heck, this humble scribe has a binocular and a trinocular microscope on the bench next to him, and doesn’t even consider that unusual. If you’re hungry for an easily hackable, extendable and cost-effective scope, then this may be just the dish you were looking for.

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