Unusual Port Combines DisplayPort And HDMI

March 12, 2024 by 22 Comments

Everyone knows you can’t plug an HDMI cable into a DisplayPort… port, and yet a recent video from [Jon Bringus] challenges that seemingly obvious assumption. The hardware in question is a variant of the 2013-era Xi3 X7A mini PC, code-named ‘Piston’ and also known as a ‘Steambox’, from back when that was still something that Valve was working on. Although the physical format here is definitely quaint, it might be implementing DisplayPort Dual-Mode (DP++), which was introduced around the same time.

With DP++ the DP port can detect when a DVI or HDMI adapter is connected and then transmit DVI/HDMI TMDS signals rather than DP signals. Since DP and HDMI/DVI use a different signaling scheme, normally an active adapter would be required. One disadvantage of DP++ is that the HDMI signal will be limited to e.g. 1920×1080 @ 120 Hz and 4K only at 30 Hz.

Normally a DP++ port is marked as such, and requires an adapter that works with the DP++ port. What Xi3 did in this case to make regular DP and HDMI connectors work seems to be somewhat of a mystery, with any information on this type of port being rather scarce. [Jon] thinks he may have found the part itself listed on Mouser, but isn’t completely sure.

Feel free to leave your thoughts and any information you have on this oddity in the comments.

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Stressless Shortwave Reviewed

March 12, 2024 by 17 Comments

[Dan Robinson] picked up a shortwave receiver known as the “stressless” receiver kit. We aren’t sure if the stress is from building a more complicated kit or operating a more complicated receiver. Either way, it is an attractive kit that looks easy to build.

Presumably to reduce stress, the VFO and receiver boards are already built, so assembly is just a few hours connecting large components and boards. As kits go, this is a fairly simple one. We were surprised to read that the supplier says you can’t upgrade the firmware. We, of course, wonder if that’s true.

For technical specs, the receiver is AM only and can operate from 100 kHz to 30 MHz. It uses a double conversion with intermediate frequencies of 21.4 MHz and 455 kHz. There’s a BNC connector on the back, and the radio requires 11 to 15V on the input. Apparently, the frequency generator inside is an SI5351. The sensitivity and selectivity numbers look very good for an AM radio.

We were surprised to see the radio didn’t have provisions for SSB since AM-only makes it not as useful for hams or others interested in non-broadcast transmissions. If we are doing our conversions correctly, the kit is fairly pricey, too, especially considering that it is AM only.

Still, we like that you could easily assemble a nice-looking radio kit. We were interested in hearing it perform, and [Dan’s] video lets us virtually try it out without the effort. We’ve seen the SI5351 on a carrier if you want to roll your own. Come to think of it, we’ve seen several.

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A 555-Shaped Discrete Component 555

March 11, 2024 by 2 Comments

While the “should have used a 555” meme is strong around these parts, we absolutely agree with [Kelvin Brammer]’s decision to make this 555-shaped plug-in replacement for the 555 timer chip using discrete parts, rather than just a boring old chip.

As [Kelvin] relates, this project started a while back as an attempt to both learn EDA and teach students about the inner workings of the venerable timer chip. The result was a 555-equivalent circuit on a through-hole PCB, with the components nicely laid out into the IC’s functional blocks. As a bonus, the PCB was attached to an 8-pin header which could be plugged right in as a direct replacement for the chip.

Fast forward a few years, and [Kelvin] needed to learn yet another EDA package; what better way than to repeat the 555 project? It was also a good time to step into SMD design, as well as add a little zazzle. While the updated circuit isn’t as illustrative of the internal arrangement of the 555, the visual celebration of the “triple nickel” is more than worth it. And, just like the earlier version, this one has a header so you can just plug and chug — with style.

Want to know how the 555 came to be? We’ve covered that. You can also look at some basic 555 circuits to put your 555-shaped 555 to work. We’ve even seen a vacuum tube 555 if that’s more your thing.

3D Imaging For Natural Science — For Free

March 11, 2024 by 4 Comments

It isn’t that unusual for a home lab to have a microscope, but wouldn’t it be cool to have a CT scanner? Well, you probably won’t anytime soon, but if you are interested in scans of vertebrates — you know, animals with backbones — a group of museums have you covered.

The oVert project is scanning 20,000 specimens and making the results available to everyone. This should be a boon to educators and might even be useful for 3D printing animal forms. Check out the video about the project below.

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Playing ZX Spectrum’s Manic Miner On The Arduino Uno

March 11, 2024 by 14 Comments
Composite output shield with audio driver and controller inputs for Arduino Uno (Credit: Scott Porter)
Composite output shield with audio driver and controller inputs for Arduino Uno (Credit: Scott Porter)

Although it seems many have moved on to 32-bit MCUs these days for projects, there is still a lot of fun to be had in the 8-bit AVR world, as [Scott Porter] demonstrates with a recent Arduino Uno project featuring his game engine running a port of the Manic Miner game that was originally released in 1983 for the ZX Spectrum. For the video and audio output he created an add-on board for the Uno that creates a composite signal using two resistors, along with an audio driver circuit and control inputs either from the onboard buttons or from a NES controller. Audio can be sent either over the composite output or via the audio jack.

A demonstration of the game is provided in a number of videos on [Scott]’s YouTube account, which shows off a few levels, at 256×256 resolution. It contains all 20 original levels, with a few quality of life upgrades with animation. It also features original music, which may or may not work for you, but music can be turned on or off in the main menu. Compared to the 3.5 MHz Z80 MPU in the ZX Spectrum, the 16 MHz AVR of the Uno is a lot beefier, which raises the hope that a color version like the ZX Spectrum one is also in the future, even if it may require an add-on board with a framebuffer. As [Scott] notes, the weakness of the Uno is that the ZX Spectrum has significantly more RAM, which limits what can be done.

Thanks to [256byteram] for the tip.

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Hack Makes Microwave Cookies Fast And Not Terrible

March 11, 2024 by 36 Comments

Making a chocolate chip cookie is easy. Making a good chocolate chip cookie is a little harder. Making a good chocolate chip cookie quickly is a pretty tall order, but if you cobble together a microwave and a conventional oven, you just might get delicious and fast to get together.

The goal of this Frankenstein-esque project is to build a vending machine that can whip up a fresh-baked chocolate chip cookie on demand and make [Chaz] wealthy beyond his wildest dreams. We’re guessing at that last part; for all we know his goal is world peace through instant cookies. We’re fine with the idea either way, and his previous work on the project resulted in a semi-automatic cookie gun to splooge the dough out in suitable dollops.

The current work is turning those into something edible, for which a microwave seems a logical choice. Experience tells us otherwise, so off to the thrift store went [Chaz], returning with a used air fryer. He ripped the guts out of a small microwave, slapped the magnetron onto the side of the air fryer, and discovered that this was officially A Bad Idea™ via a microwave leakage tester. Round 2 went the other way — adding a conventional heating element to a large microwave. That worked much better, especially after close-up video revealed the dynamics of microwave cookery and the best way to combine the two cooking modalities. The result is a contraption that makes a pretty tasty-looking two-minute cookie. World peace, here we come!

Of course there’s plenty to say about the safety of all this, much of which [Chaz] himself cops to in the video. It’s important to remember that he’s just prototyping here; we’re sure the final machine will be a little more sophisticated than a heat gun duct-taped to the side of a microwave. Those cookies aren’t going to bake themselves, though, so you’ve got to start somewhere.

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Share Your Projects: KiCad Automations And Pretty Renders

March 11, 2024 by 23 Comments

I have a pretty large GitHub repository, with all of my boards open-sourced there. Now, I’m finally facing the major problem it has – it can be uncomfortable for others to work with. I don’t store Gerber files in the repository because that will interfere with how Git functions – you’re supposed to only have source files in the repo. Yet, when someone needs Gerbers for my PCB, or a schematic PDF, or just to see how the board looks before they clone the entire repository, I often don’t have a good option for them.

In my experience as a hacker, being able to find others’ PCBs on GitHub is simply wonderful, but a PCB repository without a README feels barren, and a PCB README without pictures makes me sad. On the other hand, not having these files autogenerate is uncomfortable – updating a picture every time is a major drawback in particular.

Let’s take a look at some KiCad Git integrations, and see what they have to offer.

kicad_cli

We’ve mentioned kicad_cli back when KiCad 7 got released, and in the recently released KiCad 8, it’s only become more powerful. Before, it could do gerbers and schematic PDFs, but now, it can even do DRC checks – which is ideal if you want to add a hook for any pull requests you might encounter.

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