analog

167 Articles

Alpakka: A Creative Commons Game Controller

December 22, 2022 by 21 Comments

Input Labs’ mission is to produce open-source Creative Commons hardware and software for creating gaming controllers that can be adapted to anyone. Alpakka is their current take on a generic controller, looking similar to a modern Xbox or PlayStation controller but with quite a few differences. The 3D printed casing has a low-poly count, angular feel to it, but if you don’t like that you can tweak that in blender to just how you want it. Alpakka emulates a standard USB-attached keyboard, mouse, and Xinput gamepad in parallel so should just work out of the box for both Linux and Windows PC platforms. The firmware includes some built-in game profiles, which can be selected on the controller.

No special parts here, just 3D prints, a PCB and some nuts and bolts

The dual D-pads, augmented with an analog stick, is not an unusual arrangement, but what is a bit special is the inventive dual-gyro sensor arrangement –which when used in conjunction with a touch-sensitive pad — emulates a mouse input. Rest your thumb on the right-hand directional pad and the mouse moves, or else it stays fixed, kind of like lifting a mouse off the pad to re-center it.

The wired-only controller is based around a Raspberry Pi Pico, which has plenty of resources for this type of application giving a fast 250 Hz update rate. But to handle no fewer than nineteen button inputs, as well as a scroll wheel, directional switch, and that analog stick, the Pico doesn’t have enough I/O, needing a pair of NXP PCAL6416A I2C IO expanders to deal with it.

The PCB design is done with KiCAD, using a simple 3D printed stand to hold the PCB flat and the through-hole components in place while soldering. Other than a few QFN packages which might be a problem for some people, there is nothing tricky about hand-soldering this design.

We’ve been seeing custom game controllers as long as we’ve been hacking, here’s an interesting take on the mouse-integration theme. If you’re comfortable rolling the hardware side of things, but the firmware is a sticking point, then perhaps look no further than this neat RP2040 firmware project.

Continue reading “Alpakka: A Creative Commons Game Controller” →

Faceless Clock Makes You Think Twice About How It Works

November 18, 2022 by 23 Comments

We love projects that make you do a double-take when you first see them. It’s always fun to think you see one thing, but then slowly realize everything is not quite what you expected. And this faceless analog clock is very much one of those projects.

When we first saw [Shinsaku Hiura]’s “Hollow Clock 4,” we assumed the trick to making it look like the hands were floating in space would rely on the judicious use of clear acrylic. But no, this clock is truly faceless — you could easily stick a finger from front to back. The illusion is achieved by connecting the minute hand to the rim of the clock, and rotating the whole outer circumference through a compact 3D printed gear train. It’s a very clever mechanism, and it’s clear that it took a lot of work to optimize everything so that the whole look of the clock is sleek and modern.

But what about the hour hand? That’s just connected to the end of the minute hand at the center of the clock’s virtual face, so how does that work? As it is with most things that appear to be magical, the answer is magnets. The outer rim of the clock actually has another ring, this one containing a pair of neodymium magnets. They attract another magnet located in the very end of the hour hand, dragging it along as the hour ring rotates. The video below shows off the secrets, and it gives you some idea of how much work went into this clock.

We’re used to seeing unique and fun timepieces and other gadgets from [Shinsaku Hiura] — this up-flipping clock comes to mind, as does this custom RPN calculator — but this project is clearly a step beyond.

Continue reading “Faceless Clock Makes You Think Twice About How It Works” →

Seven Segments, But Not As We Know Them

October 6, 2022 by 11 Comments

We’ve seen a lot of clever re-imagining of the classic 7-segment display, and proving there is still room for something new is [Jack]’s 7-segment “DigiTag” display.

This 3D printable device has a frame into which is slotted three sliders. These sliders can be adjusted individually, mixing and matching the visibility of colored and uncolored areas, to create digits 0-9. We’ve seen some unusual 7-segment-inspired displays before, using from one motor for the whole digit to ones that need one motor per segment, but nothing quite like this approach.

While this particular design relies on the user to manually “dial in” each digit, the resulting key-like assembly (and unique shape for each digit) seems like it could have some interesting applications — a puzzle box design comes to mind.

If you have any ideas of your own on how this could be used, don’t keep them to yourself! Let us know in the comments, below.

Mouse Finds New Home In Pinball Machine

October 3, 2022 by 14 Comments

Restoring pinball machines is an excellent hobby, and can even be more than that as we see businesses like bars and museums focusing on them as a main attraction. There’s all kinds of intrigue to be found, from esoteric mechanical systems to classic electronics and unique artwork. For those building new pinball machines, though, one way to bypass a lot of the hassle of finding antiquated parts is to build a digital machine with an analog feel, like this machine which repurposes a computer mouse in an interesting way.

One of the important design considerations with a more modern system like this is to preserve the mechanical components that the player interacts with, in this case the plunger. This pinball machine is really just a large screen driven by a computer, but the plunger is a spring-loaded one from an old analog machine. Attached to the end of the plunger inside the cabinet is a cloth strap which passes underneath an old optical mouse. When the plunger is pulled and released, the mouse registers the position of the plunger and sends that information to the computer controlling the pinball display.

We really appreciate a KISS-style design like this in general. Mice are a proven, reliable technology and the metal components of the plunger are unlikely to ever wear out, which means that at least this part of the new pinball machine is unlikely to need much maintenance over the lifespan of the cabinet itself. For other ways of preserving the original feel of old machines, take a look at this build which incorporates all kinds of tricks within a MAME cabinet.

A Solar-Powered Point-and-Shoot, Circa 1961

September 27, 2022 by 23 Comments

Try to put yourself in the place of an engineer tasked with building a camera in 1961. Your specs include making it easy to operate, giving it automatic exposure control, and, oh yeah — you can’t use batteries. How on Earth do you accomplish that? With a very clever mechanism powered by light, as it turns out.

This one comes to us from [Alec Watson] over at Technology Connections on YouTube, which is a channel you really need to check out if you enjoy diving into the minutiae of the mundane. The camera in question is an Olympus Pen EES-2, which was the Japanese company’s attempt at making a mass-market 35-mm camera. To say that the camera is “solar-powered” is a bit of a stretch, as [Alec] admits — the film advance and shutter mechanism are strictly mechanical, relying on springs and things to power them. It’s all pretty standard camera stuff.

But the exposure controls are where this camera gets interesting. The lens is surrounded by a ring-shaped selenium photocell, the voltage output of which depends on the amount of light in the scene you’re photographing. That voltage drives a moving-coil meter, which waggles a needle back and forth. A series of levers and cams reads the position of the needle, which determines how far the lens aperture is allowed to open. A clever two-step cam allows the camera to use two different shutter speeds, and there’s even a mechanism to prevent exposure if there’s just not enough light. And what about that cool split-frame exposure system?

For a camera with no electronics per se, it does an impressive job of automating nearly everything. And [Alec] does a great job of making it interesting, too, as he has in the past with a deep-dive into toasters, copy protection circa 1980, and his take on jukebox heroics.

Continue reading “A Solar-Powered Point-and-Shoot, Circa 1961” →

Reverse Engineering An Apollo-Era Module With X-Ray

June 29, 2022 by 9 Comments

The gear that helped us walk on the Moon nearly 60 years ago is still giving up its mysteries today, with some equipment from the Apollo era taking a little bit more effort to reverse engineer than others. A case in point is this radiographic reverse engineering of some Apollo test gear, pulled off by [Ken Shirriff] with help from his usual merry band of Apollo aficionados.

The item in question is a test set used for ground testing of the Up-Data Link, which received digital commands from mission controllers. Contrary to the highly integrated construction used in Apollo flight hardware, the test set, which was saved from a scrapyard, used more ad hoc construction, including cards populated by mysterious modules. The pluggable modules bear Motorola branding, and while they bear some resemblance to ICs, they’re clearly not.

[Ken] was able to do some preliminary reverse-engineering using methods we’ve seen him employ before, but ran into a dead end with his scope and meter without documentation. So the modules went under [John McMaster]’s X-ray beam for a peek inside. They discovered that the 13-pin modules are miniature analog circuits using cordwood construction, with common discrete passives stacked vertically between parallel PCBs. The module they imaged showed clear shadows of carbon composition resistors, metal-film capacitors, and some glass-body diodes. Different angles let [Ken] figure out the circuit, which appears to be part of a square wave to sine wave converter.

The bigger mystery here is why the original designer chose this method of construction. There must still be engineers out there who worked on stuff like this, so here’s hoping they chime in on this innovative method.

Digital To Analog In The Darkroom

April 27, 2022 by 7 Comments

As the world becomes more and more digital, there are still a few holdouts from the analog world we’ve left behind. Vinyl records are making quite the comeback, and film photography is still hanging on as well. While records and a turntable have a low barrier for entry, photography is a little more involved, especially when developing the film. But with the right kind of equipment you can bridge the gap from digital to analog with a darkroom setup that takes digital photographs and converts them to analog prints.

The project’s creator, [Muth], has been working on this project since he found a 4K monochrome display. These displays are often used in resin 3D printers, but he thought he could put them to use developing photographs. This is much different from traditional darkroom methods, though. The monochrome display is put into contact with photo-sensitive paper, and then exposed to light. Black pixels will block the light while white pixels allow it through, creating a digital-to-analog negative of sorts. With some calibration done to know exactly how long to expose each “pixel” of the paper, the device can create black-and-white analog images from a digital photograph.

[Muth] notes that this method isn’t quite as good as professional print, but we wouldn’t expect it to be. It creates excellent black-and-white prints with a unique method that we think generates striking results. The 4K displays needed to reproduce this method aren’t too hard to find, either, so it’s fairly accessible to those willing to build a small darkroom to experiment. For those willing to go further, take a look at some other darkroom builds we’ve seen in the past.

Continue reading “Digital To Analog In The Darkroom” →