Day: November 21, 2022

A Game Boy Advance – Downgraded!

November 21, 2022 by 6 Comments

We feature a large number of game console mods here, because enhancing the experience of using a classic machine often involves some really clever work. But here’s one that’s a bit different, instead of upgrading his Game Boy Advance, [Wenting Zhang] has downgraded it from a colour screen to a monochrome LCD. Take a look at the video below the break.

One might ask why this would be necessary, given that there are plenty of backlit colour LCD upgrades already for the GBA, but perhaps people who played the original might understand that it’s about improving the viewability over the rather poor-quality colour LCD original.

Interesting too is the choice of display controller. Where it might be expected to find an FPGA, instead there’s an PR2040. He goes into detail about its programming, and we hope it might inspire any others looking at screen transplants. Meanwhile if the name [Wenting Zhang] means anything to you, it should be for his other work with mono LCDs.

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Better Air Quality Sensing With CO2

November 21, 2022 by 19 Comments

Measuring air quality, as anyone who has tried to tackle this problem can attest, is not as straightforward as it might seem. Even once the nebulous term “quality” is defined, most sensors use something as a proxy for overall air health. One common method is to use volatile organic compounds (VOCs) as this proxy but as [Larry Bank] found out, using these inside a home with a functional kitchen leads to a lot of inaccurate readings. In the search for a more reliable sensor, he built this project which uses CO2 to help gauge air quality.

Most of the reason that CO2 sensors aren’t used as air quality sensors is cost. They are much more expensive than VOC sensors, but [Larry] recently found one that was more affordable and decided to build this project around it. The prototype used an Arduino communicating over I2C to the sensor and an OLED screen, which he eventually put in a 3D printed case to carry around to sample CO2 concentration in various real-world locations. The final project uses a clever way of interfacing with the e-paper display that we featured earlier.

While CO2 concentration doesn’t tell the full story of air quality in a specific place, it does play a major role. [Larry] found concentrations as high as 3000 ppm in his home, which can cause a drop in cognitive function. He’s made some lifestyle changes as a result which he reports has had a beneficial impact. For human-occupied indoor spaces, CO2 can easily be the main contributor to poor air quality, and we’ve seen at least one other project to address this concern directly.

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 8 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 89 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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