Custom Built 12-Port A/V Switch Keeps CRT Well Fed

March 30, 2021 by Tom Nardi 5 Comments

Classic gaming aficionados who prefer to play on real hardware know the struggle of getting their decades-old consoles connected to a modern TV. Which is why many gamers chose to keep a contemporary CRT TV around for when they want to take a walk down memory lane. Unfortunately those old TVs usually didn’t offer more than a few A/V ports on the back, so you’ll probably need to invest in a A/V switch to keep them all hooked up at once.

That’s the situation [Thomas Sowell] found himself in, except he couldn’t find one with enough ports. Rather than chain switches together, he decided to build his own custom 12-port console selector. With an integrated amplifier to keep everything looking sharp, a handsome walnut and metal enclosure, and a slick graphical interface that shows the logo of the currently selected console on a Vacuum Fluorescent Display (VFD), the final product is a classic gamer’s dream come true.

To switch the audio [Thomas] is using a pair of ADG1606 16-channel analog multiplexers, while video is shuffled around with four MAX4315 8-channel video multiplexer-amplifiers. The math might seem a bit off at first, but he’s using one ADG1606 for each stereo channel and since the switch is for S-Video, each device has a luminance and color signal that needs to be handled separately. The multiplexers are flipped with a ATmega2561 microcontroller, which is also responsible for reading user input from a rotary encoder on the front of the case and displaying the appropriate console logo on the 140×32 Noritake VFD.

You may be surprised to find that [Thomas] considered himself an electronics beginner when he started this project, and that this is only the second PCB he’s ever designed. Was this a bold second project? Sure. But it also speaks to how far DIY electronics has come over the last years. Powerful open source tools, modular components, and of course a community of creative folks willing to share their knowledge and designs, has gone a long way towards redefining whats possible for the individual hacker and maker.

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The Most Annoying Among Us Tasks Created In Real Life

November 22, 2020 by Lewin Day 12 Comments

Among Us is a hit game of deception and intrigue. Those who have played it know the frustration of trying to complete some of the intentionally difficult tasks onboard the Skeld. [Zach Freedman] decided to recreate some of these in real life.

[Zach] built what are arguably the three most frustrating tasks from the game. There’s the excruciatingly slow upload/download station built out of an old Samsung tablet and an NFC tag, and the reactor start console created using a Raspberry Pi 3B, Teensy 3.2, and a custom mechanical keyboard. But perhaps most annoying of all is the infamous card reader. Built with another Teensy, it requires the user to swipe their ID card at just the right speed, except that speed is randomly generated for every swipe. Also, the machine fails 20% of good swipes just because. Perhaps what we love most is the way [Zach] recreated the classic VFD look by putting an OLED display behind bottle-green plastic and using a 14-segment font.

It’s a fun homage to a wildly successful indie game, and we could imagine these props would be a hit at a makerspace party. We’ve featured other Among Us themed builds before, too. Video after the break.

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Sunrise, Sunset, Repeat

August 25, 2020 by Kristina Panos 5 Comments

Sunrises and sunsets hardly ever disappoint. Still, it’s difficult to justify waking up early enough to catch one, or to stop what you’re doing in the evening just to watch the dying light. If there’s one good thing about CCTV cameras, it’s that some of them are positioned to catch a lovely view of one of the two, and a great many of them aren’t locked down at all.

[Dries Depoorter] found a way to use some of the many unsecured CCTV cameras around the world for a beautiful reason: to constantly show the sun rising and setting. Here’s how it works: a pair of Raspberry Pi 3B + boards pull the video feeds and display the sunrise/sunset location and the local time on VFD displays using an Arduino Nano Every. There isn’t a whole lot of detail here, but you can probably get the gist from the high-quality pictures.

If you wanted to recreate this for yourself, we might know where you can find some nice CCTV camera candidates. Just look through this dystopian peephole.

Thanks for the tip, [Luke]!

An Old Calculator Lives Again

August 24, 2020 by Al Williams 42 Comments

There was a time when any electronics student would have a slide rule hanging off their belt. By the 1970s, the slide rule changed over to an electronic calculator which was a pricy item. Today you can buy calculators at the dollar store. [JohnAudioTech] pulled out an old Radio Shack vacuum fluorescent display (VFD) calculator and found it didn’t work. Obviously, that means it is time to open it up.

It is fun to see one of these old devices opened up again. Consumer electronics with big through-hole ICs! Troubleshooting the device wound up being anti-climatic, as a broken wire to the battery compartment explained the whole thing.

As a teardown, though, this is a fun video. Not only are all the parts through-hole, but the PCB is clearly a manual layout with serpentine traces flowing across the board like some sort of art piece. Continue reading “An Old Calculator Lives Again” →

A Practical Look At Chokes For EMI Control

March 15, 2020 by Dan Maloney 6 Comments

Radio frequency electronics can seem like a black art even to those who intentionally delve into the field. But woe betide the poor soul who only incidentally has to deal with it, such as when seeking to minimize electromagnetic interference. This primer on how RF chokes work to reduce EMI is a great way to get explain the theory from a practical, results-oriented standpoint.

As a hobby machinist and builder of machine tools, [James Clough] has come across plenty of cases where EMI has reared its ugly head. Variable frequency drives are one place where EMI can cause problems, and chokes on the motor phase outputs are generally prescribed. He used an expensive choke marketed as specific for VFD applications on one of his machines, but wondered if a cheap ferrite core would do the job just as well, and set to find out.

A sweep of some ferrite cores with a borrowed vector network analyzer proved unsatisfying, so [James] set up a simple experiment with a function generator and an oscilloscope. His demo shows how the impedance of a choke increases with the frequency of the test signal, which is exactly the behavior that you’d want in a VFD – pass the relatively low-frequency phase signals while blocking the high-frequency EMI. For good measure, he throws a capacitor in parallel to the choke and shows how much better a low-pass filter that makes.

We love demos like this that don’t just scratch an intellectual itch but also have a practical goal. [James] not only showed that (at least in some cases) a $13 ferrite can do the same job as a $130 VFD choke, but he showed how they work. It’s basic stuff, but it’s what you need to know to move on to more advanced RF filter designs.

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A Network Attached VFD Tube Clock

February 6, 2020 by Tom Nardi 12 Comments

The elegance of Power over Ethernet (PoE) is that you can provide network connectivity and power over a single cable. Unfortunately not nearly enough hardware seems to support this capability, forcing intrepid hackers to take matters into their own hands. The latest in this line of single-cable creations is this beautiful Vacuum Fluorescent Display (VFD) clock from [Glen Akins].

One of the key advantages VFDs have over their Nixie predecessors is greatly reduced energy consumption, and after [Glen] ran the numbers, he saw that a display using six VFD tubes could easily be powered with standard PoE hardware. With this information, he started designing the PCB around the early 1990s era IV-12 tube, which has the advantage of being socketed so he could easily remove them later if necessary.

[Glen] first had to create a schematic and PCB footprint for the IV-12 tube that he could import into Eagle, which he was kind enough to share should anyone else be working with these particular tubes down the line. After a test of the newly designed socket was successful, he moved onto the rest of the electronics.

The clock is powered by a Microchip PIC18F67J60, which connects to the Ethernet network and pulls the current time down from NTP. After seeing so many clocks use an ESP to connect to the Internet over WiFi, there’s something refreshing about seeing a wired version. The tube segments are driven by a HV5812, also Microchip branded. Lastly, [Glen] used a number of DC/DC converters to generate the 1.5 V, 3.3 V, 5 V, and 25 V necessary to drive all the electronics and VFDs.

We absolutely love the simplicity of this clock, from its sleek aluminum enclosure to that single RJ45 jack on the back. But if you’re looking for something with a bit more flash, [Glen] also put together some PoE Christmas lights over the holidays which share a number of design elements with this project.

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A VFD Wall Thermometer

December 28, 2019 by Tom Nardi 5 Comments

Want to build something using VFD tubes, but don’t need yet another clock project? In that case, this wall mounted temperature and humidity display created by [commanderkull] might be exactly what you’re looking for. With six IV-11 tubes, this display is a practical way to add some of that gorgeous blue-green glow to your home or office.

The USB powered display uses a XL6009 and an XL7015 to provide the 24 V and 1.8 V needed by the IV-11 tubes, respectively. Both of which can be disconnected with jumpers to shut down the tubes without powering off the entire device, a useful feature when programming and debugging the display’s ATmega328P microcontroller. Each tube is connected to the ATmega with an 74HC595 shift register and a UDN2981 driver. Temperature and humidity data is provided, perhaps unsurprisingly, by the exceptionally common DHT22 sensor.

If you are looking to build another clock with these style tubes, there’s certainly enough prior art out there to get you started. We’ve also seen faux VFDs that you could use for either project, just in case you aren’t looking to deal with the voltage requirements and relative rarity of the real thing.