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.

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3D Printed Light Pipe Turns Overly-Bright LED Into Design Harmony

December 22, 2022 by 14 Comments

There are a number of ways to efficiently and elegantly limit an LED’s brightness, but [Tommy] found that using a light pipe or diffuser can integrate better with a device, especially when the device itself is mostly 3D printed in the first place.

Infill has an effect on appearance. 20% infill on the left, 100% infill on the right.

For some problems the Goldilocks approach is the way to go. [Tommy] designed a small array of different LED cover options, and tested each to see what yielded the best results for his printed kit. Some of the biggest takeaways include:

  • 100% infill is best for even results (although interesting shadows happen at less than 100% infill.)
  • Interesting things happen with 7 to 11 mm of top layers of clear PLA, when illuminated from below with a 5 mm high-brightness LED. An even diffusion of light starts to give way to a circular gradient as the upper layer gets thicker.
  • LEDs emit their light mainly upward in a round pattern. Corners will always be darker, even more so if the guide is not round. This effect becomes noticeably more pronounced as the light guide grows in size, putting a practical upper limit on its effective dimensions.

[Tommy] explores these kinds of issues because he designs and builds electronic synth instruments, and they are mostly 3D printed. He explores efficiency and is always happy to share his findings about what works and doesn’t work.

Of course, the usual ways to deal with an overly-bright LED are to limit its current or control its brightness by driving it with a PWM signal. The right approach depends on the application and the scale of the design, and there are actually quite a few ways to crack this nut. Luckily, our own [Inderpreet Singh] is here to tell you all about how best to control LED brightness.

A Modern Tribute To The Classic HP-16C Calculator

December 21, 2022 by 19 Comments

The HP-16C Computer Scientist is much beloved as the only dedicated programmer’s calculator that Hewlett-Packard ever made. Most surviving examples in the world are well-used, and you haven’t been able to order one from HP since 1989. Thus, [K Johansen] set about building a tribute to the HP-16C using modern hardware.

The build relies on a Raspberry Pi Pico as the brains of the operation. As with so many classic HP calculators, it operates in Reverse Polish Notation, and includes the customary stack operations. To serve a programmer well, it’s set up to accept entry in hexadecimal, octal, decimal, and binary formats, and can readily convert between them. Beyond that, it’s equipped with the usual arithmetic operators, as well as bitwise operations like NOT, AND, and so on.

Perhaps what we love most, though, is the keypad. It was all put together with a combination of cheap AliExpress keypads, a label maker, and a laser printer. It’s a wholly DIY job, and a little rough around the edges, but it makes the calculator far easier to use.

It’s not an exact replica of the HP-16C, but the differences in operation are minor.Those wishing to build their own can grab the required files from the project’s Github page. We’ve seen replicas of other classic HP calculators before, too. If you’ve got your own mathematical projects brewing up in the lab, don’t hesitate to send them in to the tipsline!

 

Chumby Gets New Kernel… Soon

December 21, 2022 by 18 Comments

If you missed the Chumby, we’re sorry.  They were relatively inexpensive Linux appliances that acted as a clock, Internet radio, and feed reader. The company went belly up, although there was some functionality remaining thanks to one of the founders and now, for a subscription fee, you can still keep your Chumby operating. However, [Doug Brown] bought one with the goal of using it for his own applications. But the 2.6.28 kernel is showing its age. So he decided to push a new kernel on the device.

If you are a Chumby enthusiast, don’t get too excited. The goal isn’t to provide the existing Chumby apps with a new kernel, [Doug] says that’s probably impossible. Instead, he wants a modern booting infrastructure and kernel on the device for his own software.

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Sliding Wrench Leaves A Little To Be Desired

December 21, 2022 by 29 Comments

[Ben Conrad] received an interesting tool as a gift that purported to be a better mousetrap. It was a crescent wrench (made by the Crescent company, even) that didn’t have a tiny adjusting wheel like a traditional wrench. Instead, it had a slide running down the length of the handle. The idea is that you would push the slide to snug the wrench jaws against the bolt or nut, and that would be fast and easy compared to a conventional wrench. As [Ben] notes, though, it doesn’t work very well. Most of us would have just dumped it in the back of the tool chest or regifted it. [Ben] tore his apart to find out what was wrong with it.

A typical adjustable wrench has four parts. This one has 19 parts and looks like a conventional wrench with an extra slide and screw running down the length of the handle. [Ben] found the parts were poorly made, but that wasn’t the main problem.

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LED Christmas Lights Optimized For Max Twinkleage

December 21, 2022 by 12 Comments

Old-school filament-based Christmas lights used to be available in twinkling form. LEDs, with their hard-on and hard-off nature, aren’t naturally predisposed to such behavior. To rectify this, some time ago, [Mark Kriegsman] built an Arduino program that makes LEDs twinkle beautifully.

The program is known as TwinkleFOX, and relies on the popular FastLED library for addressable LEDs. [Mark’s] demo setup is built around using WS2811 LEDs, put together in a string with plastic diffusers on each bulb. The Arduino is programmed to vary the brightness of each LED according to a triangle wave function. To create the twinkling effect, each LED has its own unique clock signal, so they vary in brightness at different times and at different rates.

Using an Arduino Uno or Leonardo, [Mark] reports its possible to twinkle 300 individual LEDs at a rate of over 50 updates a second. Using a faster microcontroller should net reliable performance with longer strings. Meanwhile, if you’re wondering how the older-style lights used to twinkle, we’ve covered that before too. Video after the break.

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2022 FPV Contest: The LOTP Robot Dog

December 21, 2022 by 7 Comments

When you think of first person view (FPV) vehicles, aircraft might be what first comes to mind. However, [Limenitis Reducta] has brought a robot dog into the world, and plans to equip it for some FPV adventures.

LOTP pictured with various equippable modules.

The robot dog itself goes by the name of LOTP, for unspecified reasons, and was designed from the ground up in Fusion 360. A Teensy 3.5 is charged with running the show, managing control inputs and outputting the requisite instructions to the motor controllers to manage the walk cycle. Movement are issued via a custom RC controller. Thanks to an onboard IMU, the robotic platform is able to walk effectively and maintain its balance even on a sloping or moving platform.

[Limenitis] has built the robot with a modular platform to support different duties. Equitable modules include a sensor for detecting dangerous gases, a drone launching platform, and a lidar module. There’s also a provision for a camera which sends live video to the remote controller. [Limenitis] has that implemented with what appears to be a regular drone FPV camera, a straightforward way to get the job done.

It’s a fun build that looks ready to scamper around on adventures outside. Doing so with an FPV camera certainly looks fun, and we’ve seen similar gear equipped on other robot dogs, too.

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