Misc Hacks

4137 Articles

Calculus Made Easy In The Car

July 29, 2022 by 24 Comments

If you had the traditional engineering education, you’ve made your peace with calculus. If you haven’t, you may have learned it on your own, but for many people, calculus has a reputation for being super difficult. While some of the details can be very tricky, the core concepts are actually simple and [Mathologer] has a very simple explanation along with some good graphics that can help you get started on calculus mastery if you’ve been putting it off. Using a car on the highway as the prototypical example, he covers quite a bit of ground in the 30 minute video that you can see below.

Of course, this isn’t a unique idea that calculus is actually simple. The video credits the great book “Calculus Made Easy” that we’ve talked about before. That 100-year-old (and then some) book has a similar approach to the topic.

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Simple Universal Modem Helps Save And Load Data From Tape

July 27, 2022 by 22 Comments

Back in the early days of the home computer revolution, data was commonly saved on tape. Even better, those tapes would make an almighty racket if you played them on a stereo, because the data was stored in an audio format.  The Simple Universal Modem from [Anders Nielsen] is built to work in a similar way, turning data into audio and vice versa.

The project consists of a circuit for modulating data into audio, and demodulating audio back into data. It’s “universal” because [Anders] has designed it to be as format-agnostic as possible. It doesn’t matter whether you want to store data on a digital voice recorder, a cassette deck, or an old reel-to-reel. This build should work fairly well on all of them!

On the modulation side of things, it’s designed to be as analog-friendly as possible. Rather than just spitting out rough square waves, it modulates them into nice smooth sine waves with fewer harmonics. On the demodulation side, it’s got an LM393 comparator which can read data on tape and spit out a clean square wave for easy decoding by digital circuitry.

If you find yourself trying to recover old data off tapes, or writing to them for a retrocomputing project, this build might be just what you need. [Anders] even goes as far as demonstrating its use with an old reel-to-reel deck in a helpful YouTube video.

There really were some weird ways of storing data way back when. Just ask IBM. Video after the break.

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OpenJewelry, No Pliers Required

July 25, 2022 by 2 Comments

They say that if you want something done right, you gotta do it yourself. Oftentimes, that goes double for getting something done at all. Whereas some people might simply lament the lack of a (stable) Thingiverse-type site for, say, jewelry designs, those people aren’t Hackaday’s own [Adam Zeloof]. With nowhere to share designs among engineering-oriented friends, [Adam] took the initiative and created OpenJewelry, a site for posting open-source jewelry and wearable art designs as well as knowledge about techniques, materials, and processes.

[Adam] has seeded the site with a handful of his own beautiful designs, which run the gamut from traditional silversmithing techniques to 3D printing to fancy PCBs with working blinkenlights. You really should check it out, and definitely consider contributing.

Even if you don’t have any jewelry designs to share, the code is open as well, or you could even edit the wiki. Just be sure to read through the contribution guidelines first. If you don’t have the time for any of that, donations are welcome as well to help maintain the site.

We love wearable art around here, especially when it serves another purpose like this UV-sensing talisman, or this air quality necklace.

A Tiny Forest Of Resistors Makes For Quick And Dirty Adaptive Optics

July 25, 2022 by 16 Comments

The term “adaptive optics” sounds like something that should be really complicated and really expensive. And in general, the ability to control the properties of optical elements is sufficiently difficult enough that it’s reserved for big-science stuff like billion-dollar space telescopes.

But that doesn’t mean there aren’t quick and dirty adaptive optics that are suitable for the budget-minded experimenter, like this thermally deformable mirror. As [Zachary Tong] explains, this project, which started quite some time ago, is dead simple — a 4 by 4 array of through-hole resistors stand on end, and these are attached to a glass coverslip that has been aluminized on one side. An Arduino and a couple of shift registers make it possible to individually address each of the 16 resistors in the array. Passing a current through a resistor heats it up a bit, leading to thermal expansion and a slight deflection of the mirror sitting on top of the array. Controlling which resistors heat up and by how much should lead to deformation of the mirror surface in a predictable way.

The video below shows some of [Zach]’s experiments with the setup. Unfortunately, he wasn’t able to fully demonstrate its potential — the low-quality mirror didn’t cooperate with his homebrew interferometer. He was, however, able to use a dial indicator to show deflection of the mirror in the 2- to 3-micron range by heating the array. That alone is pretty cool, especially given the dirt cheap nature of the build.

As for practical uses, don’t get too excited. As [Zach] points out, thermal systems like this will probably never be as fast as MEMS or piezoelectric actuators, and many use cases for adaptive optics really don’t react well to added heat. But changing the shape of a mirror with air pressure is another thing.

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Hack Your Brain: Bionic Reading — Panacea Or Placebo?

July 23, 2022 by 17 Comments

In the Star Trek episode Space Seed, [Khan] famously said, “Improve a mechanical device, and you may double productivity. But improve man, you gain a thousandfold.” Most of our hacks center on the mechanical or electromechanical kind, but we do have an interest in safely improving ourselves. The problem is that most of us don’t want to mess with our DNA or have surgery, so it sort of limits our options.

We are always interested in less invasive hacks, so we certainly took note of Bionic Reading. However, a recent paper claims to debunk the claims of benefits. The company promoting the technology claims a Swiss University study showed that while the results were not clear, “the majority had a positive effect.” They also claim, anecdotally, that the technique can help those with dyslexia. What’s the truth? We don’t know, but it is an interesting discussion to follow.

If you haven’t seen it before, Bionic Reading — which, by the way, may not be free to use — is a way of using a dark font to emphasize certain key parts of words. For example, you can read this article using Bionic Reading. [Daniel Doyon] analyzed reading by 2,074 testers and found that participants actually read slower when using the Bionic Reading technique.

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ESP32 Gets A Nifty Serial Console Library

July 22, 2022 by 8 Comments

Sometimes you need to get a project to talk to you, so you can see what’s going on inside. The ESP32 console Arduino library from [jbtronics] promises just that.

The library adds a simple serial console to the ESP32, and is compatible with the Arduino ecosystem to boot. It’s set up to allow the easy addition of custom commands so you can tweak the console to suit your own projects. It’s remarkably complete with nifty features, too. There’s autocomplete as well as a navigable command history – the sorts of features you only expect from a modern OS terminal. A bunch of system commands are built-in, too, for checking the status of things like the memory, network interface, and so on.

The tool is available via the Arduino library manager or the PlatformIO registry. You’ll want to use it with a VT-100 compatible terminal like PuTTY or similar, which lets you use all the fancy features including color output. [jbtronics] hopes to port it to the ESP8266 soon, too!

We’ve seen some other great serial tools of late, too. If you’re brewing up your own nifty console hacks, be sure to drop us a line!