2024 Business Card Challenge: Tiny MIDI Keyboard

June 6, 2024 by 17 Comments

The progress for electronics over the past seven decades or so has always trended towards smaller or more dense components. Moore’s Law is the famous example of this, but even when we’re not talking about transistors specifically, technology tends to get either more power efficient or smaller. This MIDI keyboard, for example, is small enough that it will fit in the space of a standard business card which would have been an impossibility with the technology available when MIDI first became standardized, and as such is the latest entry in our Business Card Challenge.

[Alana] originally built this tiny musical instrument to always have a keyboard available on the go, and the amount of features packed into this tiny board definitely fits that design goal. It has 18 keys with additional buttons to change the octave and volume, and has additional support for sustain and modulation as well. The buttons and diodes are multiplexed in order to fit the IO for the microcontroller, a Seeed Studio Xiao SAMD21, and it also meets the USB-C standards so it will work with essentially any modern computer available including most smartphones and tablets so [Alana] can easily interface it with Finale, a popular music notation software.

Additionally, the project’s GitHub page has much more detail including all of the Arduino code needed to build a MIDI controller like this one. This particular project has perhaps the best size-to-usefulness ratio we’ve seen for compact MIDI controllers thanks to the USB-C and extremely small components used on the PCB, although the Starshine controller or these high-resolution controllers are also worth investigating if you’re in the market for compact MIDI devices like this one.

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Foosbar: The World’s Best* Foosball Robot From Scratch

June 6, 2024 by 6 Comments

[Xander Naumenko] is back with another bonkers project. This is the same creator that built a working 32-bit computer inside a Terraria world. This time it’s a bit more physical of a creation: a self-playing foosball table.

We’re not sure of the impetus for this idea, but we’re delighted to see the engineering it took to make it work. It sounds so simple. It’s just servos mounted on linear actuators, right? Oh, and some computer vision to determine where the ball actually is on the table. And the software to actually control the motors, pass the ball around, and play offense and defense. So maybe not so simple. All the code and some other resources are available under the MIT license.

As to while the claim of “best” foosball robot has an asterisk? That’s because, although we’ve seen a few potential competitors over the years, there isn’t yet a world foosball competition. We’re hoping that changes, as a tournament of robots playing foosball sounds like a sports event we’d show up for!

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Retrotechtacular: TVO

June 6, 2024 by 18 Comments

Hardware hackers come from a variety of backgrounds, but among us there remains a significant number whose taste for making things was forged through growing up in a farm environment. If that’s you then like me it’s probable that you’ll melt a little at the sight of an older tractor, and remember pretending to drive one like it at pre-school age, and then proudly driving it for real a few years later before you were smart enough to realise you’d been given the tedious job of repeatedly traversing a field at a slow speed in the blazing sun. For me those machines were Ford Majors and 5000s, Nuffields, the ubiquitous red Fergusons, and usually relegated to yard duty by the 1970s, the small grey Ferguson TE20s that are in many ways the ancestor of all modern tractors.

The Black Art Of Mixing Your Own Fuel

There was something odd about some of those grey Fergies in the 1970s, they didn’t run on diesel like their newer bretheren, nor did they run on petrol or gasoline like the family Austin. Instead they ran on an unexpected mixture of petrol and heating oil, which as far as a youthful me could figure out, was something of a black art to get right. I’d had my first encounter with Tractor Vapour Oil, or TVO, a curious interlude in the history of agricultural engineering. It brings together an obscure product of the petrochemical industry, a moment when diesel engine technology hadn’t quite caught up with the on-farm requirement, and a governmental lust for a lower-tax tractor fuel that couldn’t be illicitly used in a car.

TVO is a fuel with a low octane rating, where the octane rating is the resistance to ignition through compression alone. In chemical terms octane rating a product of how many volatile aromatic hydrocarbons are in the fuel, and to illustrate it your petrol/gasoline has an octane rating in the high 90s, diesel fuel has one close to zero, and TVO has a figure in the 50s. In practice this was achieved at the refinery by taking paraffin, or kerosene for Americans, a heavier fraction than petrol/gasoline, and adding some of those aromatic hydrocarbons to it. The result was a fuel on which a standard car engine wouldn’t run, but which would run on a specially low-compression engine with a normal spark ignition. This made it the perfect tax exempt fuel for farmers because it could only be used in tractors equipped with these engines, and thus in the years after WW2 a significant proportion of those Fergies and other tractors were equipped to run on it. Continue reading “Retrotechtacular: TVO” →

What’s The Difference Between Tang 9K And 20K (It Isn’t 11…)

June 6, 2024 by 18 Comments

[Grug Huhler] has been working with the Tang Nano 9K FPGA board. They are inexpensive, and he noticed there is a 20K version, so he picked one up. Of course, you’d expect the 20K board has a different FPGA with more gates than the 9K, but there are also a number of differences in the host board. [Grug] was kind enough to document the differences in the video below.

In addition to the differences, there’s a good demo of the boards hosting a system-on-chip design. The little DIP package is handy for breadboarding. All of the 20K pins are 3.3 V, according to the documentation. The 9K does have some 1.8 V pins. There are more external devices on the 20K board but that eats up more uncommitted pins. Depending on your design, that may or may not be a problem.

We keep meaning to pick some of these up to play with. The Verilog is easy enough, and the tools look adequate. If you need a refresher on Verilog, we have a boot camp for you that would probably port easily enough to the Tang system. We’ve been following [Grug’s] work on these chips lately, and you should, too.

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Hands On: Inkplate 6 MOTION

June 6, 2024 by 11 Comments

Over the last several years, DIY projects utilizing e-paper displays have become more common. While saying the technology is now cheap might be overstating the situation a bit, the prices on at least small e-paper panels have certainly become far more reasonable for the hobbyist. Pair one of them with a modern microcontroller such as the RP2040 or ESP32, sprinkle in a few open source libraries, and you’re well on the way to creating an energy-efficient smart display for your home or office.

But therein lies the problem. There’s still a decent amount of leg work involved in getting the hardware wired up and talking to each other. Putting the e-paper display and MCU together is often only half the battle — depending on your plans, you’ll probably want to add a few sensors to the mix, or perhaps some RGB status LEDs. An onboard battery charger and real-time clock would be nice as well. Pretty soon, your homebrew e-paper gadget is starting to look remarkably like the bottom of your junk bin.

For those after a more integrated solution, the folks at Soldered Electronics have offered up a line of premium open source hardware development boards that combine various styles of e-paper panels (touch, color, lighted, etc) with a microcontroller, an array of sensors, and pretty much every other feature they could think of. To top it off, they put in the effort to produce fantastic documentation, easy to use libraries, and free support software such as an online GUI builder and image converter.

We’ve reviewed a number of previous Inkplate boards, and always came away very impressed by the attention to detail from Soldered Electronics. When they asked if we’d be interested in taking a look at a prototype for their new 6 MOTION board, we were eager to see what this new variant brings to the table. Since both the software and hardware are still pre-production, we won’t call this a review, but it should give you a good idea of what to expect when the final units start shipping out in October.

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Tarzan, Lost Since 1983, Swings Back Onto The Atari 2600

June 6, 2024 by 12 Comments

Computer gaming history is littered with tales of fabled lost hardware and software. Some of them are very famous such as the E.T. cartridges buried in a desert landfill or the few prototype SNES/CD-ROM hybrid that Nintendo was developing with Sony before the introduction of the PlayStation, but others have faded somewhat into obscurity. Among these is Tarzan for the Atari 2600, a game which was never released due to the 1983 console crash, and which the [Video Game History Foundation] have a report on its rediscovery and preservation.

The game was to be published by Coleco for their ColecoVision console as well as the 2600. The ColecoVision version was released and was apparently even fairly well reviewed, but the Atari port was canceled and its very existence eventually faded into obscurity.

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Is That A Triboelectric Generator In Your Shoe?

June 6, 2024 by 20 Comments

The triboelectric effect is familiar to anyone who has rubbed wool on a PVC pipe, or a balloon on a childs’ hair and then stuck it on the wall. Rubbing transfers some electrons from one material to the other, and they become oppositely charged. We usually think of this as “static” electricity because we don’t connect the two sides up with electrodes and wires. But what if you did? You’d have a triboelectric generator.

In this video, [Cayrex] demonstrates just how easy making a triboelectric generator can be. He takes pieces of aluminum tape, sticks them to paper, and covers them in either Kapton or what looks like normal polypropylene packing tape. And that’s it. You just have to push the two sheets together and apart, transferring a few electrons with each cycle, and you’ve got a tiny generator.

As [Cayrex] demonstrates, you can get spikes in the 4 V – 6 V range with two credit-card sized electrodes and fairly vigorous poking. But bear in mind that current is in the microamps. Given that, we were suprised to see that he was actually able to blink an LED, even if super faintly. We’re not sure if this is a testament to the generator or the incredible efficiency of the LED, but we’re nonetheless impressed.

Since around 2012, research into triboelectric nanogenerators has heated up, as our devices use less and less power and the structures to harvest these tiny amounts of power get more and more sophisticated. One of the coolest such electron harvesters is 3D printable, but in terms of simplicity, it’s absolutely hard to beat some pieces of metal and plastic tape shoved into your shoe.

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