Wooden Disc Player Translates Binary Back Into Text

September 18, 2020 by Kristina Panos 10 Comments

[jbumstead] used MATLAB to convert the text messages into binary to be cut out of the disk.

[jbumstead] wanted to demonstrate the idea of information-storing devices such as LPs, CDs, and old hard drives. What he came up with lies directly at the intersection of art and technology: an intricately-built machine that plays beautiful collaged wooden disks. Much like the media that inspired the Wooden Disk Player, it uses a laser to read encoded data, which in this case is short bits of text like “Don’t Panic”.

These snippets are stored in binary and read by a laser and photodiode pair that looks for holes and not-holes in the disk. The message is then sent to an Arduino Nano, which translates it into English and scrolls the text on an LED matrix. For extra fun, the Nano plays a MIDI note every time it reads a 1, and you can see the laser reading the disk through a protective acrylic shield.

Though the end result is fantastic, [jbumstead] had plenty of issues along the way which are explored in the build video after the break. We love it when people show us their mistakes, because it happens to all of us and we shouldn’t ever let it tell us to stop hacking.

If anyone knows their way around lasers, it’s [jbumstead]. We loved playing their laser harp at Supercon!

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Roll Your Own Heelys

September 17, 2020 by Kristina Panos 17 Comments

Remember Heelys, the shoes with wheels in the heels? Just lift up your toes, and away you go. We were at least ten or fifteen years older than the target demographic, but got a pair anyway just to please our inner child and have some fun. Young kids would wear them everywhere and zip around inside stores to the annoyance of everyone but other young kids. We imagine some shopkeepers got to the point where they could spot the things as they walked in the door and nipped the skating party in the bud.

[DevNerd] has conceived of the ultimate plan: if you make your own Heelys, no one necessarily has to know unless you start rolling around. [DevNerd] started by cutting some large, 20mm-deep holes in the bottoms of a pair of Air Jordans and printed a sturdy wheel and a box frame for support.

Each wheel has a bearing on both ends that spin on a threaded rod. We’re not sure why [DevNerd] went with threaded rod, because it seems like that would prematurely wear out the frame box.

Don’t want to cut up your shoes, but want some sweet roller kicks for the daily commute down the hall? You could always make them out of pallet wood.

Distance Learning Land

September 16, 2020 by Orlando Hoilett 7 Comments

[familylovermommy] has been homeschooling her kids even before the pandemic, so she’s pretty well-versed on being a learning coach and a teacher. One of the activities she designed for her boys has them creating 3D models using Tinkercad. In the spirit of openness and cultivating freethinking, she did not give them very many constraints. But rather, gave them the liberty to creatively design whatever scene they imagined.

In the Instructable, she shares her sons’ designs along with instructions to recreate the models. The designs as you’ll see are pretty extensive, so she embedded the Tinkercad designs directly into it. You can even see a number of video showcases as well.

This is a really cool showcase of some pretty stellar workmanship. Also, maybe a bit of inspiration for some of our readers who are creating work from home activities of their own.

While you’re at it, check out some of these other work-from-home hacks.

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Deep-Sleep Problems Lead To Forensic Investigation Of Troublesome Chip

September 15, 2020 by Dan Maloney 53 Comments

When you buy a chip, how can you be sure you’re getting what you paid for? After all, it’s just a black fleck of plastic with some leads sticking out of it, and a few laser-etched markings on it that attest to what lies within. All of that’s straightforward to fake, of course, and it’s pretty easy to tell if you’ve got a defective chip once you try it out in a circuit.

But what about off-brand chips? Those chips might be functionally similar, but still off-spec in some critical way. That was the case for [Kevin Darrah] which led to his forensic analysis of potentially counterfeit MCU chips. [Kevin] noticed that one of his ATMega328 projects was consuming way too much power in deep sleep mode — about two orders of magnitude too much. The first video below shows his initial investigation and characterization of the problem, including removal of the questionable chip from the dev board it was on and putting it onto a breakout board that should draw less than a microamp in deep sleep. Showing that it drew 100 μA instead sealed the deal — something was up with the chip.

[Kevin] then sent the potentially bogus chip off to a lab for a full forensic analysis, because of course there are companies that do this for a living. The second video below shows the external inspection, which revealed nothing conclusive, followed by an X-ray analysis. That revealed enough weirdness to warrant destructive testing, which showed the sorry truth — the die in the suspect unit was vastly different from the Atmel chip’s die.

It’s hard to say that this chip is a counterfeit; after all, Atmel may have some sort of contract with another foundry to produce MCUs. But it’s clearly an issue to keep in mind when buying bargain-basement chips, especially ones that test functionally almost-sorta in-spec. Caveat emptor.

Counterfeit parts are depressingly common, and are a subject we’ve touched on many times before. If you’d like to know more, start with a guide.

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The Jolly Cart-Pushing Robot

September 14, 2020 by Orlando Hoilett 4 Comments

[Lance] loves making simple robots with his laser cutter. He finds great satisfaction from watching his robots operate using fairly simple mechanisms and designs a whole slew of them inspired by different animals, including a dinosaur and a dragon. His latest build is a jolly cart-pushing robot.

He cut each piece of his robot on his laser cutter, and in order to get the pieces to fit snugly together he made each tab a little bigger than its corresponding slot, ensuring the piece wouldn’t fall out. This also helps account for the loss in the material due to kerf, which is the bit of each piece of material that gets lost in the cut end of the laser cutter.

Making his robot walk was mostly as easy as attaching each leg to a simple DC motor such that the motor would rotate each leg in succession, pushing the robot along. From time to time, [Lance] also had to grease the robot’s moving parts using a bit of wax to help reduce friction. He even used a little rubber band to give the robot some traction.

[Lance] did a pretty good job detailing the build in his video. He also linked to a few other fun little robot designs that could entertain you as well. Pretty easy hack, but we thought you might find the results as satisfying as we did.

Robot companions may be here to stay. Time will tell.

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Digging In The Dirt Yields Homebrew Inductors

September 13, 2020 by Dan Maloney 16 Comments

Let’s say you’re stranded on a desert island and want to get the news from the outside world. You’ll have to build your own crystal radio, of course, but your parts bin is nowhere to be found and Digi-Key isn’t delivering. So you’ll need to MacGuyver some components. Capacitors are easy with a couple of pieces of tinfoil, and a rectifier can be made from a pencil and a razor blade. But what about an inductor? Sure, air-core inductors will work, but just because you’re marooned doesn’t mean you’ve abandoned your engineering principles. Luckily, you’ve read [AC7ZL]’s treatise of making inductors from dirt, and with sand in abundance, you’re able to harvest enough material to put together some passable ferrite-core inductors.

Obviously, making your own inductive elements isn’t practical even in fanciful and contrived situations, but that doesn’t make the doing of it any less cool. The story begins with a walk in the Arizona desert many years ago, where [AC7ZL], aka [H.P. Friedrichs], spied bands of dark sand shooting through the underlying lighter sediments. These bands turned out to be magnetite, one of many iron-bearing minerals found in the area. Using a powerful magnet from an old hard drive and a plastic food container, he was able to harvest magnetite sand in abundance and refine it with multiple washing steps.

After experimentally determining the material’s permeability — about 2.3 H/m — [AC7ZL] proceeded with some practical applications. He was able to make a bar antenna for an AM radio by packing the sand into a PVC pipe and rewinding the coils around it. More permanent cores were made by mixing the sand with polyester resin and casting it into bars. Toroids were machined from fat bars of the composite on a lathe, much to the detriment of the cutting tools used.

The full-length PDF account of [AC7ZL]’s experiments makes for fascinating reading — the inductive elements he was able to create all performed great in everything from a Joule Thief to a Hartley oscillator up to 27 MHz. We love these kinds of stories, which remind us of some of the work being done by [Simplifier] and others.

USB Bell Rings In Custom Terminal

September 13, 2020 by Al Williams 13 Comments

Old TeleTypes and even typewriters had bells. Real bells. So that ASCII BEL character is supposed to make an honest to goodness ringing sound. While some modern terminals make a beep from the computer speakers, it isn’t the same. [Tenderlove] must agree, because the turned a Microchip USB to I2C bridge chip into a HID-controlled bell.

The only problem we see is that you have to have a patch to your terminal to ring the bell. We’d love to see some filter for TCP or serial that would catch BEL characters, but on the plus side, it is easy to ring the bell from any sort of application since it responds to normal HID commands.

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