Portable ESP32 RGB Lasershow Has All The Trimmings

November 21, 2022 by 47 Comments

Perhaps there was a time when fancy laser effects were beyond those without the largest of bank accounts, but today they can be created surprisingly easily. [Corebb] shows us how with a neat unit using an off the shelf RGB laser module and mirror module, driven by a ESP32 with software designed to make it as easy as possible to use.

The video below the break is in Chinese so you’ll have to turn on the subtitles if you’re an Anglophone, and it takes us through the whole process. It’s mounted in an SLA 3D printed enclosure which neatly holds all the parts. The ESP32 module drives a couple of DACs which in turn drive the galvanometer motors through a pair of amplifiers.

Then the software allows all sorts of custom displays for your creative expression, including uploading quick sketches over WiFi. Beyond pretty patterns we see it mounted on a bicycle for a head-up display of speed and navigation info. Even if it does fall off and break at one point we can see that could be an extremely useful accessory.

All the code can be found in a GitHub repository should you wish to try for yourself. Meanwhile we’ve covered a lot of laser projector projects here in the past, including most recently this one using stepper motors in place of galvanometers.

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Reverse Engineering “The Seven Words (and More) You Can’t Say On TV”

November 21, 2022 by 24 Comments

For as visionary as he was, [George Carlin] vastly underestimated the situation with his classic “Seven Words You Can’t Say on TV” bit. At least judging by [Ben Eater]’s reverse engineering of the “TVGuardian Foul Language Filter” device, it seems like the actual number is at least 20 times that.

To begin at the beginning, a couple of weeks ago [Alec] over at everyone’s favorite nerd hangout Technology Connections did a video on the TVGuardian, a device that attempted to clean up the language of live TV and recorded programming. Go watch that video for the details, but for a brief summary, TVGuardian worked by scanning the closed caption text for naughty words and phrases, muted the audio when something suggestive was found in a lookup table, and inserted a closed caption substitute for the offensive content. In his video, [Alec] pined for a way to look at the list of verboten words, and [Ben] accepted the challenge.

The naughty word list ended up living on a 93LC86 serial EEPROM, which [Ben] removed from his TVGuardian for further exploration. Rather than just plug it into a programmer and dumping the contents, he decided to roll his own decoder with an Arduino, because that’s more fun. And can we just point out our ongoing amazement that [Ben] is able to make watching someone else code interesting?

The resulting NSFW word list is titillating, of course, and the video would be plenty satisfying if that’s where it ended. But [Ben] went further and figured out how the list is organized, how the dirty-to-clean substitutions are made, and even how certain words are whitelisted. That last bit resulted in the revelation that Hollywood legend [Dick Van Dyke] gets a special whitelisting, lest his name becomes sanitized to a hilarious [Jerk Van Gay].

Hats off to [Alec] for inspiring [Ben]’s fascinating reverse engineering effort here.

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Making SVD Files Searchable With Svd2db

November 21, 2022 by 11 Comments

Everyone who writes bare-metal code for microcontrollers probably know the joys of looking up the details of specific registers in the reference manual, including their absolute address. Although the search function of the PDF viewer can be helpful, it’d be rather nice if there was a way to search only the registers, and have the offset calculations performed automatically. This is basically what [Terry Porter]’s Svd2db tool enables. As the name suggests, this tool turns the SVD hardware description files that come with ARM-based MCUs into a database file.

This database file is an SQLite database, which allows it to be searched using the provided readdb tool, or any other SQLite tool. This would make the utility useful not just for quick look-ups during development, but presumably also for automated testing scenarios where having an easily searchable database of registers is of use. At this point Svd2db is guaranteed to work with STM32 SVDs, but may work with SVDs for other ARM-based SVD files as well.

 

How To Repair? The Death Of Schematics

November 21, 2022 by 97 Comments

There was a time when, if you were handy with a soldering iron, you could pretty easily open up a radio or TV repair business. You might not get rich, but you could make a good living. And if you had enough business savvy to do sales too, you could do well. These days there aren’t many repair shops and it isn’t any wonder. The price of labor is up and the price of things like TVs drops every day. What’s worse is today’s TV is not only cheaper than last year’s model, but probably also better. Besides that, TVs are full of custom parts you can’t get and jam-packed into smaller and smaller cases.

Case in point, I saw a “black Friday” ad for a 40-inch 1080p flatscreen with a streaming controller for $98. Granted, that’s not huge by today’s standards and I’m sure it isn’t a perfect picture. But for $98? Even a giant high-quality TV these days might cost a bit more than $1,000 and you can get something pretty great for well under $500.

Looking back, a Sears ad showed a great deal on a 19″ color TV in 1980. The price? $399. That doesn’t sound too bad until you realize that today that would be about $1,400. So with a ratio of about 3.5 to 1, a $30/hour service call would be, today, $105. So for an hour’s service call with no parts, I could just buy that 40″ TV. Add even one simple part or another hour and I’m getting close to the big league TVs.

Did you ever wonder how TV repair technicians knew what to do? Well, for one thing, most of the time you didn’t have to. A surprising number of calls would be something simple like a frayed line cord or a dirty tuner. Antenna wires destroyed by critters was common enough. In the tube days, you could pretty easily swap tubes to fix the bulk of actual problems.

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Making A Do-It-Yourself Sand Battery

November 21, 2022 by 96 Comments

Storing energy can be done in many ways, with the chemical storage method of a battery being one of the most common. Another option is a thermal battery, which basically means making something hot, and later extracting that heat again. In this video by [Robert Murray-Smith] the basic concept of a thermal battery that uses sand is demonstrated.

By running a current through a resistive wire that’s been buried inside a container with sand, the sand is heated up to about 200 °C. As [Robert] points out, the maximum temperature of the sand can be a 1000 °C or more. Because sand doesn’t boil like water, the total amount of energy stored in sand is correspondingly higher.

Extracting the thermal energy can be done rather inefficiently using the demonstrated Peltier element. A Stirling engine, or steam generator and turbine, would get a lot more energy out. Either way, the thermal battery itself is made using just plain sand, which makes it an attractive DIY target to tinker with.

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FDA’s Approval Of Cell Culture Chicken: The Rise Of Fresh Meat Without The Animal?

November 21, 2022 by 105 Comments

On November 14th of this year, the FDA cleared the path for Upside Foods to sell its cell-culture-based chicken products within the US. This is the first product of its kind to be cleared for commercial sale within the Americas, with only Singapore having previously cleared a similar product for sale, back in December of 2020. This latter product comes courtesy of another California start-up called Eat Just.

Since that initial approval in Singapore, Eat Just has begun to set up a 2,800 square meter (~30,000 square feet) production facility in Singapore that is scheduled to begin producing thousands of kilograms of slaughter-free meat starting in the first quarter of 2023. This would make it the top-runner in the cultured meat industry, which to this point has seen dozens of start-ups, but precious few actual products for sale.

With CEO Josh Tetrick of Eat Just projecting price equality between their cultured meat and meat from animals by 2030, could the FDA’s approval herald the dawn of slaughter-free meat? There are obviously still hurdles, but as we’ll see, the idea is not nearly as far-fetched as one might think.

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Move Aside Planar, I’m Slicing My Cone Way

November 21, 2022 by 12 Comments

Fleetwood Mac puns aside, very little has changed about how we “slice” models for printers in the last 30 years. However, [Stefan Hermann] of CNC Kitchen has a demo that tries to change all that by slicing conically.

For the uninitiated in the dark arts of printing in the third dimension, the canonical definition of non-conical slicing has been to bisect the model at layer height intervals and generate the perimeter and the infill, then output that as g-code. This is easy to implement mathematically and works reasonably well, except when you have overhangs of more than about 60 degrees on most printers. The idea of slicing in a cone rather than a plane isn’t entirely novel as we previously covered RotBot, which offers a vertical axis of rotation and a print head at 45 degrees. What is extraordinary is that the technique [Stefan] walks you through is done with a stock printer without a complex 45-degree tilt and is a software modification rather than a hardware tweak.

[Stefan] references earlier work done by [Michael Wüthrich] of ZHAW School of Engineering, who wrote some scripts that apply the transformation. The slicer is SuperSlicer, a fork of the PrusaSlicer, which is itself a fork of slic3r. The modified g-code is exported and can be sent to a printer of your choice. He even has a link to a pre-sliced model to try it out.

Of course, different printers have different clearance levels, but the Prusa Mini he uses has 16 degrees of clearance with the sensor pushed up. The code is on GitHub. It’s fascinating to note how all these techniques and forks interact and build off each other. Whether tilted slices, conical slices, or something else ultimately becomes the de facto standard, we’re looking forward to more options for slicing.

Video after the break.

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