Yet Another DIY Handheld Pi Gaming Console

The Raspberry Pi is a great platform for running retro video games, and with the addition of some buttons, a TFT screen and some speakers it’s relatively inexpensive and easy to get a working console up and running. If you have access to even a cheap 3D printer, a good-looking DIY console is well within reach for not a lot of money. YouTube user [DIY Engineering] has a bunch of consumer-grade fabrication tools and has designed and built a high-end but still DIY RetroPi gaming console, the RKDR II.

Among the tools that [DIY Engineering] has are both a FDM and DLP 3D printer, a reflow oven, a couple of different CNC machines and a laser cutter. They are all consumer grade, but not necessarily cheap – especially combined! [DIY Engineering] uses Fusion3D to model the case, bezel and circuit board, the latter of which is a 4 layer board designed in Eagle and sent off to be fabbed. The buttons, D-pad, screen and battery are bought off the shelf, but everything else is DIY. Check out the video for the details – the tools used, and the design files, are linked in the information section under the video on YouTube.

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Quantum Computing With QISKit

We all know that quantum computing is coming, but it is hard to know how to get started with it. [Mtreinish] suggests Qiskit — an Apache Licensed SDK for developing quantum applications. He has a presentation he gave in Singapore that you can see below, and a notebook you can go through on GitHub. If you are impatient, you can even run the notebook online through Google.

The tools can work against several backends including a simulator or the real hardware available from IBM. The official site has a different notebook you can use as a tutorial. Interestingly, the foundation of all Qiskit programs is “Terra” (the Earth) and permeating all Qiskit elements is Aer or air. There are also fire and water elements. At the bottom of the official notebook, you’ll find a lot of community notebooks that go deeper into specific topics.

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Custom Inflatables Are Only A Laser Beam Away

Carl Sagan one said “If you wish to make an apple pie from scratch, you must first invent the universe.” It might not be a very accurate description of the relative difficulty level of baking, but the logic is sound enough: there’s often a lot of ground work that needs to be to covered before you hit your ultimate goal. A perfect example of this principle is the inflatable raft that [ralph124c] hopes to eventually create; before he can set sail he has to perfect making balloon animals with his laser cutter.

In the long run, the raft will be constructed from sheets of TPU coated fabric that are fused together with a hot iron. But before he spends the time and money on building the real thing, he wants to do some scaled down tests to make sure his design works as expected. He makes a cryptic remark about learning the hard way that inflatables are prone to bouts of strange behavior, and out of an overabundance of caution we’ll just take his word for it.

He hoped to test his designs with the much cheaper LDPE film, but he found that the hot iron didn’t fuse it together in the way he was hoping. His mind turned to his 60 watt laser cutter, and wondered if the desired effect could be achieved by turning the power down as low as possible and quickly moving across the material.

His first attempts either blew right through the film or did absolutely nothing, but eventually he had the bright idea to move the laser farther from the LDPE. This put the beam out of focus, which not only expanded the area it would cover, but reduced the energy being delivered to the surface. With a bit more experimentation, he found he was able to neatly weld the pieces of material together. He even found that he could increase the power slightly to cut through the film without having to adjust the laser focus. With the ability to create complex inflatable shapes, perhaps [ralph124c] will create balloon version of Carl Sagan or an apple pie to celebrate.

Of course, this technology isn’t limited to birthday balloons and model rafts. The ability to quickly and easily produce custom inflatable shapes could be a huge boon to anyone working in soft robotics, and we’ve even seen similar concepts applied to haptic feedback systems.

[Thanks to Arthur for the tip.]

A Word Clock, The Hard Way

We’ve all seen word clocks, and they’re great, but there are only so many ways to show the time in words. This word clock with 114 servos is the hard way to do it.

We’re not sure what [Moritz v. Sivers] was aiming for with this projection clock, but he certainly got it right. The basic idea is to project the characters needed to compose the time messages onto a translucent PVC screen, which could certainly have been accomplished with just a simple character mask and some LEDs. But for extra effect, [Moritz] mounted each character to a letterbox mounted over a Neopixel. The letterboxes are attached to a rack and pinion driven by a micro servo. The closer they get to the screen, the sharper the focus and the smaller the size of the character. Add in a little color changing and the time appears to float out from a jumbled, unfocused background. It’s quite eye-catching, and worth the 200+ hours of printing time it took to make all the parts. Complete build instructions are available, and a demo video is after the break.

We like pretty much any word clock – big, small, or even widescreen. This one really pushes all our buttons, though.

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Farming Items With RasPi-Modified Joycons

The Pokémon games have delighted legions of Nintendo gamers over the years, and show no signs of slowing down any time soon. Despite its popularity, there are certain aspects of the games that are unarguably about simply grinding your way to success. For [Mori Bellamy], this simply wouldn’t do – yet their thirst for gold bottlecaps was insatiable. What to do? Automate it, of course.

The first step was to hack the Joycons from the Nintendo Switch. A DG333A analog switch IC was hooked up to the buttons inside, and controlled by the GPIO pins of a Raspberry PI. The joystick was then controlled with an MCP4725 DAC, allowing the system to fully emulate control inputs to the console.

With the console now under control by the Raspberry Pi, the next step was to add intelligence. Google’s Tesseract OCR platform was combined with a helping of Python code. This allows the script to read dialog boxes from the game, and use this data to determine which buttons to press to farm items.

[Mori] has provided the code on GitHub for others to use, noting that it should be generalizable to other games with a little work. Fundamentally, the underlying hardware could readily be repurposed to other controllers, too. There’s plenty of other ways to automate the drudgery of gaming, even if you have to use a touch screen. Video after the break.

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In Praise Of The App Note

When I am at a loss for an explanation in the world of electronics, I reach for my well-thumbed Horowitz & Hill. When H&H fails me which is not that often, the chances are I’ll find myself looking in an application note from a semiconductor company who is in cut-throat competition with its rivals in a bid for my attention. These companies have an extensive sales and marketing effort, part of which comes in the dissemination of knowledge.

Razor blades may be sold to young men with images of jet fighters and a subtle suggestion that a clean-shaven guy gets his girl, but semiconductor brands are sold by piquing the engineer’s interest with information. To that end, companies become publishing houses in praise of their products. They produce not only data sheets that deal with individual device, but app notes documents which cover a wider topic and tell the story of why this manufacturer’s parts are naturally the best in the world.

These app notes frequently make for fascinating reading, and if you haven’t found them yet you should head for the documentation sections of semiconductor biz websites and seek some of them out.

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Mains Power Supply for ATtiny Project is Probably a Bad Idea

When designing a mains power supply for a small load DC circuit, there are plenty of considerations. Small size, efficiency, and cost of materials all spring to mind. Potential lethality seems like it would be a bad thing to design in, but that didn’t stop [Great Scott!] from exploring capacitive drop power supplies. You know, for science.

The backstory here is that [Great Scott!] is working on a super-secret ATtiny project that needs to be powered off mains. Switching power supplies are practically de rigueur for such applications, but compared to the intended microcontroller circuit they are actually quite large, and they’ve just been so done before. So in order to learn a thing or two, [Scott!] designed a capacitive dropper supply, where the reactance of the cap acts like a dropping resistor to limit the current. His first try was just a capacitor in series with an LED; this didn’t end well for the LED.

To understand why, he reverse-engineered a few low-current mains devices and found that practical capacitive droppers need a few more components, chiefly a series resistance to prevent inrush current from getting out of hand, but also a bridge rectifier and a zener to clamp things down. Wiring up all that resulted in a working capacitive dropper supply, but a the cost of as much real estate as a small switcher, and with the extra bonus of being potentially lethal if the power supply is plugged in the wrong way. Side note: we thought German line cords were polarized to prevent this, but apparently not? (Ed Note: Nope!)

As always, even when [Great Scott!]’s projects don’t exactly work out, like a suboptimal 3D-printed BLDC or why not to bother building your own DC-AC inverter, we enjoy the learning that results.

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