Day: September 29, 2021

A conventiongoer plays Pokemon on a working Color Game Boy costume.

Convention Plays Pokemon On Giant Color Game Boy Costume

September 29, 2021 by 2 Comments

Standard cosplay is fun and all, but what is there for admirers to do but look you up and down and nitpick the details? Interactive cosplay, now that’s where it’s at. [Jaryd Giesen] knows this, and managed to pull together a working color Game Boy costume in a few days.

The original plan was to use a small projector on an arm, like one of those worm lights that helped you see the screen, but [Jaryd] ended up getting a secondhand monitor and strapping it to his chest. Then he took the rest of the build from there. Things are pretty simple underneath all that cardboard: there’s a Raspberry Pi running the RetroPie emulator, a Pico to handle the inputs, and two batteries — one beefy 12,000 mAH battery for the monitor, and a regular power pack for the Pi and the Pico.

As you’ll see in the build and demo video after the break, nearly 100 people stopped to push [Jaryd]’s buttons. They didn’t get very far in the game, but it sure looks like they had fun trying.

Since we’re still in a pandemic, you may want to consider incorporating a mask into your Halloween costume this year. Just a thought.

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Shortwave Radio Picks Up Sideband

September 29, 2021 by 14 Comments

With the push to having most of a radio receiver as part of a PC, it might seem odd to have a standalone communication receiver, but [OM0ET] reviews the latest one he picked up, an ATS25. Inside isn’t much: a battery, a speaker, an encoder, and a Si4732 that provides the RF muscle.

It appears the receiver is pretty broadband which could be a problem. [OM0ET] suggests adding selectivity in the antenna or adding an extra board to use as a bandpass filter.

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Robust I2C And SPI In Space Thanks To Bus Isolation

September 29, 2021 by 28 Comments

Imagine you’re sending a piece of hardware to space on a satellite. Unless you’re buddy-buddy with NASA, it’s pretty unlikely you’ll ever be able to head up there and fix something if it goes wrong once it’s launched. Robust design is key, so that even in the event of a failure in one component, the rest of the hardware can keep working.

The example I2C isolation circuit from [Max’s] paper. The SPI implementation is even simpler.
[Max Holliday] found himself in this exact situation, running 69 I2C and SPI devices in a single satellite. Thus, he came up with circuits to auto-isolate devices from these buses in the event of an issue. That work is the subject of a research paper now available on the TechRxiv Preprint Server.

The problem is that these simple buses aren’t always the most robust, being vulnerable to single-point failures where one bad part takes down other parts of the bus. [Max] notes that vast numbers of sensors and devices rely on these standards, and it can be difficult or prohibitively expensive to design without them, so a solution was needed.

To fix this, [Max] developed a simple external circuit that could be placed on each node of a I2C or SPI communication bus. In the event of malfunction, that node can be cut off from the bus by this circuit, allowing the rest of the system to go on functioning.

With little more than a few transistors, MOSFETs and passives, you too could protect your buses from malfunctions using these techniques. [Max] did just that on the NASA V-R3x mission which flew successfully in January 2021 if you needed any further confirmation of the value of this technique.

It’s something that won’t bother the home hobbyist building a garage door opener, but it could be of great value to those designing systems that must fail gracefully if they fail at all. Be sure to share your best tips and tricks for robust SPI and I2C buses in the comments below!

Raspberry Pi Pico Makes For Expeditious Input Device

September 29, 2021 by 28 Comments

With its copious number of GPIO pins and native USB, the Raspberry Pi Pico is arguably the ideal microcontroller for developing your own platform agnostic USB Human Input Devices. But you don’t have to take our word for it. Check out how quickly the $4 USD board allowed [Alberto Nunez] to put together a pair of foot pedals for his computer.

Wiring doesn’t get much easier than this.

A peek inside the enclosure reveals…well, not a whole lot. All that’s hiding inside that heavy-duty plastic box is the Pi Pico and some screw down terminals that let [Alberto] easily wire up the female bulkhead connectors for the pedals themselves. Incidentally, while you could certainly make your own pedals, the ones used for this project appear to be the sort of commercially available units we’ve seen used in similar projects.

With the hardware sorted, [Alberto] just needed to write the software. While he could have taken the easy way out and hard coded everything, we appreciate that his CircuitPython script loads its configuration from a text file. This allows you to easily configure which GPIO pins are hooked up to buttons, and what key codes to associate them with. He didn’t really need to go through this much effort for his own purposes, but it makes the project far easier to adapt for others, so our hats off to him.

If you’re looking for a bit more inspiration, our very own [Kristina Panos] put together a Python-powered macro foot stool that you can put under your desk for rapid fire keyboard shortcuts. Plus you can stand on it to reach the top shelf, if need be.

IC Shortage Keeps Linux Out Of Phone Charger, For Now

September 29, 2021 by 21 Comments

We’ve been eagerly following the development of the WiFiWart for some time now, as a quad-core Cortex-A7 USB phone charger with dual WiFi interfaces that runs OpenWrt sounds exactly like the sort of thing we need in our lives. Unfortunately, we’ve just heard from [Walker] that progress on the project has been slowed down indefinitely by crippling chip shortages.

At this point, we’ve all heard how the chip shortage is impacting the big players out there. It makes sense that automakers are feeling the pressure, since they are buying literally millions of components at a clip. But stories like this are a reminder that even an individual’s hobby project can be sidelined by parts that are suddenly 40 times as expensive as they were when you first put them in your bill of materials.

The new miniature compute board.

In this particular case, [Walker] explains that a power management chip you could get on DigiKey for $1.20 USD a few months ago is now in such short supply that the best offer he’s found so far is $49.70 a pop from an electronics broker in Shenzhen. It sounds like he’s going to bite the bullet and buy the four of them (ouch) that he needs to build a working prototype, but obviously it’s a no go for production.

Luckily, it’s not all bad news. [Walker] has made some good progress on the power supply board, which will eventually join the diminutive computer inside the USB charger enclosure. Part of the trick is that the device is still supposed to be a functional USB charger, so in addition to 5 VDC for the output port, the power supply also needs to produce 1.1 V, 1.35 V, 2.5 V, 3.0 V, and 3.3 V for the computer. We’re glad to see he’s taking the high road with his mains circuitry, making sure to use UL listed components and maintaining proper isolation.

When we last checked in on the WiFiWart back in July, [Walker] had already managed to boot Linux on his over-sized prototype board. Now he’s got PCBs in hand that look far closer to the final size and shape necessary to tuck them into a phone charger. It’s a shame that the parts shortage is slowing down progress, but we’re confident we’ll at least get to see a one-off version of the WiFiWart powered up before the year is out.

101 Uses For An Everready — Flashlight History

September 29, 2021 by 53 Comments

For some reason, I’m always interested in why things are called what they are. For example, I’ve been compelled in the past to research what Absorbine Senior is. Not that it is important, but Absorbine Junior is a smaller size of horse liniment, so you don’t have to buy a drum of ordinary Absorbine just to rub down your sore thumb. So it isn’t a mystery that I would find myself musing over why we call a flashlight a flashlight.

You don’t think of a flashlight as flashing, under normal circumstances, at least. Turns out the answer lies in the history of the device, its poor beginnings, and our willingness to treat imperfect components as though they were much better than they are. That last point, by the way, still has ramifications today, so even if you aren’t a fan of flashlight history, keep reading.

Portable Lighting

Ever since people learned to use fire, there’s been a desire for portable lighting. Torches, candles, and even oil lamps have all had their place. But burning things for light in small cramped spaces leaves a lot to be desired. It isn’t surprising that people quickly turned to electricity when that seemed to be feasible.

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A r0tring CS-50 scriber. You type, it writes the letters with a pen on your blueprint or technical drawing.

Plotting To Restore A R0tring CS-50

September 29, 2021 by 8 Comments

If you’re of a certain vintage and have ever done any technical drawing, chances are good that you used a r0tring of some kind, be it pencil or pen. Well, r0tring makes more than writing implements.  They also made electronic scribers — a small plotter that pens ISO lettering on technical drawings based on typed input. This was a huge time saver over doing it freehand or stenciling each letter. The CS-50 is designed to hold the top-of-the-line r0tring drawing pen, which turned out to be the most expensive part of this restoration aside from the time spent sniffing out issues.

[Atkelar] likes to open things up and give them a visual inspection before powering them on. We think this is good practice, even if the suspense kills you. But really, [Atkelar] did so much more than that. He started by replacing the likely late-80s-era coin cell even though it registered north of 3 V. Then he swapped out all the electrolytic caps and one tantalum, cleaned the rubber dome keyboard parts with a cheap electric toothbrush, (another great idea), and completely disassembled the x-y mechanism to clean and re-oil it.

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