Using The Pi Pico As ‘Programmable Hardware’ For The Apple II

August 27, 2024 by 8 Comments

When we think of programmable hardware, we think of FPGAs. But they’re not the only option. [Oliver Schmidt] has been exploring how the Raspberry Pi Pico can serve in such a role for the classic Apple II. The talk was presented at the KansasFest event this year, and it’s well worth diving into!

[Oliver] has developed A2Pico. It’s a series of Apple II peripheral cards that are based around the Raspberry Pi Pico, as you might have guessed. [Oliver] has been working in the area since 2021 with one [Glenn Jones], with the duo experimenting with connecting the versatile microcontroller directly to the slot bus of the Apple II. [Ralle Palaveev] then chimed in, developing the A2Pico hardware with solely through-hole components for ease of assembly.

A number of cards have been developed based on A2Pico, including a storage device, a Z80 CP/M card, and a specialized card to play Bad Apple on the IIGS. It’s all thanks to the versatility of the programmable I/O (PIO) peripheral inside the Raspberry Pi Pico. This device enables the Pico to be reprogrammed to handle all sorts of complicated tasks at great speed. This is particularly useful when using it to bit-bang a protocol or talk with another machine, and it serves perfectly well in this role. Basically, by reprogramming the Pico and its PIO, the A2Pico design can become any one of a number of different add-on cards.

It’s well worth diving into this stuff if you’ve ever contemplated building your own peripheral cards for 8-bit and 16-bit machines. We’ve seen some other great add-on cards for vintage machines before, too.

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Nice Retro Displays Set This Watch On Edge

August 27, 2024 by 10 Comments

A common design language for watches has evolved ever since they first started popping up in the 1500s. Whether worn on the wrist or in a pocket, watches are relatively slim front to back, with the display mounted on the face. That’s understandable given the imperatives of human anatomy. Still, it’s not the only way to arrange things, as this very cool LED matrix watch with an edge-mounted display demonstrates.

True, the unique form factor of this watch wasn’t really the point of the whole project. Rather, [Vitali]’s design was driven by a couple of things. First off were the extremely cool Hewlett Packard HDSP-2000 displays, with four 5×5 5×7 LED matrices shining through the clear cover of a DIP-12 package. Also visible through the cover are the shift registers that drive the matrices, complete with gold bonding wires.

The main attraction for [Vitali], though, was the challenge of working within the limits of the ATtiny85 he chose to run the watch. The MCU’s limited IO made hardware multiplexing necessary, no mean feat given the limited resources and real estate available. He still managed to pack everything in, with the unique edge-mount display coming from the LEDs bridging the space between the two main PCBs. Everything fits into a nice wood veneer case, although we think it looks just fine without it. [Vitali] puts it through its paces in the short video below.

Hats off to [Vitali] for a great-looking project that pushed his limits. We just love these displays, too; of course, it’s not the first time we’ve seen them put to similar use.

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The Macintosh Plus Sounds Great If You Do Exactly This With It

August 26, 2024 by 3 Comments

The Macintosh Plus is not exactly known as particularly relevant in the worlds of chiptune or electronic music more broadly. That’s not to say it can’t do anything that sounds cool, however. As [Action Retro] demonstrates,  it’s got some really impressive tricks up its sleeve if you know what you’re doing.

The video centers around “Music Mouse”, a piece of software created by Laurie Spiegel for the Macintosh Plus all the way back in 1986. Spiegel saw the Macintosh Plus as a potential instrument for musical expression, with the then-innovative mouse as the key human interface.

[Action Retro] shows off the software, which is able to create rather pleasing little melodies with little more than a swish and a swash across the mousepad. The software makes smart use of scales so you’re not forever dodging around dissonant notes, so it’s quite easy to play something beautiful. He then makes things more interesting by pairing the Macintosh Plus with his favorite guitar pedal—the Old Blood Noise Endeavors Sunlight. It’s a dynamic reverb that really opens up the sonic landscape when paired with the Mac Plus. If you’re looking for a weird avant-garde setup to take on stage at your next noise show, this has to be it.

We’re usually used to seeing Nintendo and Commodore products in the retro computer music space. The Mac makes a nice change. Video after the break.

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Robots Collaborate To Localize Themselves Precisely

August 26, 2024 by 3 Comments

Here’s the thing about robots. It’s hard for them to figure out where to go or what they should be doing if they don’t know where they are. Giving them some method of localization is key to their usefulness in almost any task you can imagine. To that end, [Guy Elmakis], [Matan Coronel] and [David Zarrouk] have been working on methods for pairs of robots to help each other in this regard.

As per the research paper, the idea is to perform real-time 3D localization between two robots in a given location. The basic idea is that the robots take turns moving. While one robot moves, the other effectively acts as a landmark. The robots are equipped with inertial measurement units and cameras in a turret, which they use to track each other and their own movements. Each robot is equipped with a Raspberry Pi 4 for processing image data and computing positions, and the two robots communicate via Bluetooth to coordinate their efforts.

It’s an interesting technique that could have some real applications in swarm robotics, and in operations in areas where satellite navigation and other typical localization techniques are not practical. If you’re looking for more information, you can find the paper here. We’ve seen some other neat localization techniques for small robots before, too. Video after the break.

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Fast 3D Printing With A Polar, Four Quadrant Custom Machine

August 26, 2024 by 14 Comments

3D printing is all well and good for making low numbers of units, so long as they’re small enough to print in a reasonable time, but what if you want to go really big? Does a 35-hour print time sound like a fun time? Would it even make it that long? [Nathan] from Nathan Build Robots didn’t fancy the wait, so they embarked on a project to build a huge parallel 3D printer with four independent print heads. Well, kind of. Continue reading “Fast 3D Printing With A Polar, Four Quadrant Custom Machine” →

It Turns Out, A PCB Makes A Nice Watch Dial

August 26, 2024 by 19 Comments

Printed circuit boards are typically only something you’d find in a digital watch. However, as [IndoorGeek] demonstrates, you can put them to wonderful use in a classical analog watch, too. They can make the perfect watch dial!

Here’s the thing. A printed circuit board is fundamentally some fiberglass coated in soldermask, some copper, maybe a layer of gold plating, and with some silk screen on top of that. As we’ve seen a million times, it’s possible to do all kinds of artistic things with PCBs; a watch dial seems almost obvious in retrospect!

[IndoorGeek] steps through using Altium Designer and AutoCAD to layout the watch face. The guide also covers the assembly of the watch face into an actual wrist watch, including the delicate placement of the movement and hands. They note that there are also opportunities to go further—such as introducing LEDs into the watch face given that it is a PCB, after all!

It’s a creative way to make a hardy and accurate watch face, and we’re surprised we haven’t seen more of this sort of thing before. That’s not to say we haven’t seen other kinds of watch hacks, though; for those, there have been many. Video after the break.

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Setup of a small lightbulb passing light through a thin film

Experimenting With Interference On Thin Layers

August 26, 2024 by No comments

[Stoppi] has taken on a fascinating project involving the interference of thin layers, a phenomenon often observed in everyday life but rarely explored in such depth. This project delves into the principles of interference, particularly focusing on how light waves interact with very thin films, like those seen in soap bubbles or oil slicks. The post is in German, but you can easily translate it using online tools.

Interference occurs when waves overlap, either reinforcing each other (constructive interference) or canceling each other out (destructive interference). In this project, [Stoppi] specifically examines how light behaves when passing through thin layers of air trapped between semi-transparent mirrors. When light waves reflect off these mirrors, the difference in path length leads to interference patterns that depend on the layer’s thickness and the wavelength of the light.

To visualize this, [Stoppi] used an interferometer made from semi-transparent mirrors and illuminated it with a bulb to ensure a continuous spectrum of light. By analyzing the transmitted light spectrum with a homemade spectrometer, he observed clear peaks corresponding to specific wavelengths that could pass through the interferometer. These experimental results align well with theoretical predictions, confirming the effectiveness of the setup.

If you like pretty patterns, soap bubbles are definitely good for several experiments. Don’t forget: pictures or it didn’t happen.

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