A Spinning Egg For Your Thoughts

October 1, 2023 by 15 Comments

Brushless motors are fascinating devices that come in all sorts of shapes and sizes, but you’ve probably never seen one in the form of a free-spinning shiny metal egg. Created by [David Windestål], [Giacomo Di Muro], and [Chad Kapper], the Motion Zero is part top, part brushless motor, and fully mesmerizing. Tech overview video after the break.

Like the classic Tippe Top toy, an ovoid shape like this shiny metal egg will stand on its end if it’s spun fast enough. To do this, the team embedded magnets in the metal egg, effectively turning it into a rotor. An array of 4 PCB coils under a smooth concave surface serves as the stator. Because the egg is not held in position by a shaft, hall effect sensors were incorporated to determine the position of the egg, and properly control the state of the coils to keep it spinning.

Recognizing how easy it was to get lost in thought while staring at a shiny spinning egg, the rest of the device was designed with meditation in mind. The top cover is a block of aluminum machined with ripple patterns, with ball bearings that slide between the ripples as the control interface. Additional hall effect sensors on the PCB determine the position of the balls to adjust the rotation speed and shut-off timer. You can even choose to make the egg move around or remain in one position. The main controller is an ESP32 module, which reads all the hall effect sensors and controls the coils via motor drivers.

The Motion Zero has made its debut on Kickstarter and already exceeded its initial funding goal. We like the creators’ willingness to share the inner workings of a product that manages to transform a simple concept into a mesmerizing piece of engineering artistry.

We’ve seen a good bit of [David Windestål]’s has a fascination with weird tech over the years, like racing belt sanders, fire breathing waterfowl, tri and bicopters. He even built a prop anti-drone RF cannon for a movie.

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A purple PCB with a Raspberry Pi Pico and an MK3870 mask ROM microcontroller

A 1970s Mask ROM MCU Spills Its Secrets

September 30, 2023 by 20 Comments

If you buy any kind of electronic gadget today, chances are it’s powered by a microcontroller with a program stored in its internal flash ROM. That program’s code is often jealously guarded by the manufacturer, who will try their best to make sure you can’t just read back the chip’s contents by using lock bits or some sort of encryption. Things were more laid back in the 1970s and ’80s, when code was stored unencrypted in standard EPROM chips, or, for high-volume applications, in mask ROMs integrated in microcontrollers. Reading back the code of such micros was still very difficult because chips simply didn’t have a way of dumping their contents. [Andrew Menadue] ran into this issue when trying to repair an old HP calculator printer, and had to apply a clever hack to dump the contents of its Mostek MK3870 chip.

The main trick [Andrew] used was one discovered by [Sean Riddle] and explained on his website. It makes use of the fact that the MK3870 has a TEST pin that can be used to disable the mask ROM and load alternative program code directly into the micro’s processing core. By setting up a LOAD instruction pointing at a ROM location and briefly disabling test mode while that instruction is executed, the ROM’s contents can be read out by the externally loaded program.

Simple as this hack may seem, actually implementing it was tricky enough because of the strict timing requirements between signals on the clock pins, the data bus, and the TEST pin. [Andrew] got it to work on his Raspberry Pi Pico setup most of the time, but somehow the micro still returned a plainly wrong value every few hundred bytes. Not willing to spend too much time debugging this issue, [Andrew] applied a rather crude hack to his code: instead of reading each byte once, it runs the read cycle 200 times, and only returns a result when all 200 runs return the same value. Dumping the entire 4 kB of ROM now takes several minutes, but this isn’t much of an issue since [Andrew] only has one chip to read out.

If you do have a bucketload of MK3870 chips that you need to dump, you might want to try and optimize the code on [Andrew]’s GitHub page. It’s a lucky coincidence that the ‘3870 has the exploitable TEST feature; often, the only way to get inside mask ROM code is by decapping the chip and optically reading the bits one by one. Mask ROMs are great for very long term data storage, however.

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Hackaday Podcast 237: Dancing Raisins, Coding On Apples, And A Salad Spinner Mouse

September 22, 2023 by 7 Comments

This week, Editor-in-Chief Elliot Williams and Kristina Panos gathered over the Internet and a couple cups of coffee to bring you the best hacks of the previous week. Well, the ones we liked best, anyhow.

First up in the news, we’ve got a brand-spankin’ new Halloween Hackfest contest running now until 9AM PDT on October 31st! Arduino are joining the fun this year and are offering some spooky treats in addition to the $150 DigiKey gift cards for the top three entrants.

It’s a What’s That Sound Results Show this week, and although Kristina actually got into the neighborhood of this one, she alas did not figure out that it was an MRI machine (even though she spent a week in an MRI one day).

Then it’s on to the hacks, which had a bit of a gastronomical bent this week. We wondered why normies don’t want to code on their Macs, both now and historically. We also examined the majesty of dancing raisins, and appreciated the intuitiveness of a salad spinner-based game controller.

From there we take a look at nitinol and its fun properties, admire some large, beautiful Nixie tubes, and contemplate a paper punching machine that spits out nonsensical binary. Finally we talk about rocker bogie suspensions and the ponder the death of cursive.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download and savor at your leisure.

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Spinning CRT Makes A 360 Degree Audio Oscilloscope

September 16, 2023 by 9 Comments

A question for you: if the cathode ray tube had never been invented, what would an oscilloscope look like? We’re not sure ourselves, but it seems like something similar to this mechanical tachyscope display might worked, at least up to a point.

What’s ironic about this scenario is that the tachyscope [Daniel Ross] built actually uses a CRT from a defunct camcorder viewfinder as the light-up bit of what amounts to a large POV display. The CRT’s horizontal coil is disconnected while the vertical coil is attached to the output of a TEA205B audio amplifier. The CRT, its drive electronics, and the amp are mounted to a motorized plastic platter along with a wireless baby monitor, to send audio to the CRT without the need for slip rings — although a Bluetooth module appears to be used for that job in the video below.

Speaking of slip rings, you’d expect one to make an appearance here to transfer power to the platter. [Daniel] used a slip ring for his previous steampunk tachyscope, but this time out he chose a hand-wound air core transformer, with a stationary primary coil and secondary coil mounted on the platter. With a MOSFET exciter on the primary and a bridge rectifier on the secondary, he’s able to get the 12 volts needed to power everything on the platform.

Like most POV displays, this one probably looks better in person than it does in video. But it’s still pretty cool, with the audio waveforms sort of floating in midair as the CRT whizzes around. [Daniel] obviously put a lot of work into this, not least with the balancing necessary to get this running smoothly, so hats off for the effort.

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Inspiration

September 16, 2023 by 55 Comments

While we were debating about whether it even makes any sense to reboot RadioShack, or indeed any brick-and-mortar electronics store in the modern era, Dan Maloney and I stumbled on what probably is the real source of all of our greybeard nostalgia for the store chain: inspiration.

For both of us, the appeal of a store like RadioShack was going through the place and thinking of what you’d do with all of those parts. Looking at the back of the beefiest MOSFET in the joint, you’d think about all the current you could pass with it. Or what you’d do with all of those piezo buzzers. And if you didn’t know yet what electronics project you wanted to make, there were things like the Forrest Mims notebooks to inspire you. There you’d find a way to turn the humble LED into a light sensor, whether you needed to or not. I wonder how many packs of assorted LEDs that book sold?!

Dan got his first hands on with a computer in RadioShack as well, because they let folks try them right there. If you didn’t know what you wanted a computer for, and that was the big question of the early microcomputer era, you could head into the store yourself and find out. Seeing, and playing with, Demon Dancer inspired.

A lot of this role is taken over by hackerspaces these days, and even more is taken by the Internet itself, of course. We have no shortage of inspiration – just read a day’s worth of Hackaday if you don’t believe me. So is there any room left for RadioShack’s inspirational role? Maybe not. But if that’s the cost of living in a world where we have access to more great ideas than we’ll ever have time to execute, then so be it!

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Backyard LED Sculpture Inspired By Las Vegas Sphere

September 15, 2023 by 19 Comments

The Las Vegas Sphere is a large building. It stands 112 meters high and 157 meters wide, and is covered in a full 54,000 square meters of LED displays. That’s a little difficult to recreate at home for the typical maker. A scaled-down version is altogether more achievable though, as demonstrated by [DrZzs & GrZzs].

The Pixelhead Megasphere, as it is known, is 1.98 meters high and 2.4 meters in diameter. That makes it altogether easier to fit in an average backyard, and it comes with a much smaller pricetag than the $2 billion used to build the Las Vegas Sphere. It runs 20,028 individual addressable LED pixels, and runs on four 12-volt 100-amp power supplies. As seen here, it’s only running at 15%, so it can go plenty brighter to really get those power supplies toasty. The sphere is controlled by Xlights, with the LEDs interfaced via Kulp controller boards. It’s able to run a variety of different animations at a good frame rate, with [DrZzs & GrZzs] busy whipping up different designs for Halloween. The eye of Sauron is a particularly nice example.

We’ve seen some other neat LED spheres before, too. Video after the break.

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