Author: Bryan Cockfield

1708 Articles

Tiny Trackpad Fits On Ergonomic Keyboard

August 6, 2024 by 5 Comments

Cats are notorious for interrupting workflow. Whether it’s in the kitchen, the garden, or the computer, any feline companion around has a way of getting into mischief in an oftentimes disruptive way. [Robin] has two cats, and while they like to sit on his desk, they have a tendency to interrupt his mouse movements while he’s using his Apple trackpad. Rather than solve the impossible problem of preventing cats from accessing areas they shouldn’t, he set about building a customized tiny trackpad that integrates with his keyboard and minimizes the chance of cat interaction.

The keyboard [Robin] uses is a split ergonomic keyboard. While some keyboards like this might use a standard USB connection to join the two halves, the ZSA Voyager uses I2C instead and even breaks the I2C bus out with a pogo pin-compatible connector. [Robin] originally designed a 3D-printed integrated prototype based on a Cirque trackpad that would clip onto the right side of the keyboard and connect at this point using pogo pins, but after realizing that the pogo pin design would be too difficult for other DIYers to recreate eventually settled on tapping into the I2C bus on the keyboard’s connecting cable. This particular keyboard uses a TRRS connector to join the two halves, so getting access to I2C at this point was as simple as adding a splitter and plugging in the trackpad.

With this prototype finished, [Robin] has a small trackpad that seamlessly attaches to his ergonomic keyboard, communicates over a standard protocol, and avoids any unwanted cat-mouse action. There’s also a build guide if you have the same keyboard and want to try out this build. He does note that using a trackpad this small involves a bit of a learning curve and a larger-than-average amount of configuration, but after he got over those two speed bumps he hasn’t had any problems. If trackpads aren’t your style, though, with some effort you can put a TrackPoint style mouse in your custom mechanical keyboard instead.

RC Car Gets Force Feedback Steering

August 6, 2024 by 8 Comments

Remote-controlled cars can get incredibly fast and complex (and expensive) the farther into the hobby you get. So much so that a lot of things that are missing from the experience of driving a real car start to make a meaningful impact. [Indeterminate Design] has a few cars like this which are so fast that it becomes difficult to react to their behavior fast enough through sight alone. To help solve this problem and bridge the gap between the experience of driving a real car and an RC one, he’s added force feedback steering to the car’s remote control.

The first thing to tackle is the data throughput required to get a system like this working wirelessly. Relying heavily on the two cores in each of a pair of ESP32s, along with a long-range, high-speed wireless communications protocol called ESP-NOW, enough data from the car can be sent to make this possible but it does rely on precise timing to avoid jitter in the steering wheel. Some filtering is required as well, but with the small size of everything in this build it’s also a challenge not to filter out all of the important high-frequency forces. With the code written, [Indeterminate Design] turned to the 3D printer to build the prototype controller with built-in motors to provide the haptic feedback.

The other half of the project involves sensing the forces in the RC car which will then get sent back to the remote. After experimenting with a mathematical model to avoid having to source expensive parts and finding himself at a deadend with that method, eventually a bi-directional load cell was placed inside the steering mechanism which solved this problem. With all of these pieces working together, [Indeterminate Design] has a working force feedback steering mechanism which allows him to feel bumps, understeer, and other sensations, especially while doing things like drifting or driving through grass, that would be otherwise unavailable to drivers of RC cars. The only thing we could think of to bring this even more into realistic simulation territory would be to add something like a first-person view like high-speed drones often have.

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Asteroids: Kessler Syndrome Edition

August 5, 2024 by 6 Comments

Asteroids, the late-70s arcade hit, was an immensely popular game. Often those with the simplest premise, while maintaining a fun, lighthearted gameplay have the most cultural impact and longest legacy. But, although it was popular, it doesn’t really meet the high bar of scientific fidelity that some gamers are looking for. That’s why [Attoparsec] built the Kessler Syndrome Edition of this classic arcade game.

The Kessler Syndrome is a condition where so much man-made debris piles up in low-Earth orbit that nothing can occupy this orbit without getting damaged or destroyed by the debris, and thus turning into more debris itself in a terrible positive feedback loop. [Attoparsec] brings this idea to Asteroids by reprogramming the game so that asteroids can be shot into smaller and smaller pieces but which never disappear, quickly turning the game into a runaway Kessler Syndrome where the chance of survival is extremely limited, and even a destroyed player’s ship turns into space junk as well.

To further the scientific accuracy and improve playability, though, he’s added a repulsor beam mechanism which can push the debris a bit and prolong the player’s life, and also added mass effect reactions so that even shooting bullets repels the player’s ship a bit. The build doesn’t stop with software, either. He also built a custom 70s-style arcade cabinet from the ground to host the game.

Asteroids is still a popular platform for unique builds like this. Take a look at a light-vector game using lasers to create the graphics, or this tiny version of the game that uses a real CRT.

Thanks to [smellsofbikes] for the tip!

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Better Battery Design Through Science

August 2, 2024 by 6 Comments

Before the age of lithium batteries, any project needing to carry its own power had to rely on batteries that were much less energy-dense and affordable. In many ways, we take modern lithium technology for granted, and can easily put massive batteries in our projects by the standards of just a few decades ago. While the affordability of lithium batteries has certainly decreased the amount of energy we need to put in to our projects to properly size batteries, there’s still a lot of work to be done if you’re working on a bigger project or just want to get the maximize the efficiency and effectiveness of your DIY battery pack.

The main problem with choosing a battery, as [ionworks] explains, is that batteries can’t be built for both high energy and high power, at least not without making major concessions for weight or cost. After diving in to all of the possible ways of customizing a battery, the battery guide jumps in to using PyBaMM to perform computational modeling of potential battery designs to hopefully avoid the cumbersome task of testing all of the possible ways of building a battery. With this tool virtually all of a battery’s characteristics can be simulated and potential problems with your setup can be uncovered before you chose (or start production of) a specific battery system.

While customizing a battery pack to this extent might not be a consideration for most of us unless the project is going to be big enough to run something like an electric car or a whole-house generator, it’s a worthwhile tool to know about as even smaller projects like ebikes can benefit from choosing the right cell for the application. Some of the nuances of battery pack design can be found in this guide to building packs from the standard 18650 cells.

Header: Lead holder, CC BY-SA 3.0 .

Getting An Old HVAC System Online

August 1, 2024 by 14 Comments

Standardization might sound boring, but it’s really a great underlying strength of modern society. Everyone agreeing on a way that a certain task should be done saves a lot of time, energy, and money. But it does take a certain amount of consensus-building, and at the time [JC]’s HVAC system was built the manufacturers still hadn’t agreed on a standard control scheme for these machines yet. But with a little ingenuity and an Arduino, the old HVAC system can be given a bit of automatic control.

The original plan for this antiquated system, once off-the-shelf solutions were found to be incompatible, was to build an interface for the remote control. But this was going to be overly invasive and complex. Although the unit doesn’t have a standard remote control system, it does have extensive documentation so [JC] was able to build a relay module for it fairly easily with an Arduino Nano Matter to control everything and provide WiFi functionality. It also reports the current status of the unit and interfaces with the home automation system.

While some sleuthing was still needed to trace down some of the circuitry of the board to make sure everything was wired up properly, this was a much more effective and straightforward (not to mention inexpensive) way of bringing his aging HVAC system into the modern connected world even through its non-standardized protocols. And, although agreeing on standards can sometimes be difficult, they can also be powerful tools once we all agree on them.

Reverse Engineering A Soundsystem’s API

July 31, 2024 by 12 Comments

We’ve all been stymied by a smart thermostat, coffee maker, or other device which would work fine on its own but ultimately seems to be worse off for having an Internet connection —  so when something actually pulls off this feat it’s quite noteworthy. [James] has a powerful set of connected speakers and while they don’t have all of the functionality he needed built-in, an included web API at least allowed him to build in the features he wanted.

The major problem with these speakers isn’t that they’re incredibly loud (although they are), but rather that the wide range of available volumes for such a loud soundsystem doesn’t leave a lot of fine adjustment in the range where [James] typically uses these speakers. To tackle the problem, he first found the web interface the speakers present and then discovered a somewhat hidden application programming interface (API) within that allows for some manual control. He built a second website which serves as a volume slider within the range he wants, and the web server sends this volume to the speakers via this API which allows much finer control than the built-in user interface.

Having a usable API included with Internet-connected devices is not always the case, although it’s a great model for any company wanting to allow their customers better control of the products they buy. If you need to roll out your own API for connected devices that don’t have one already, take a look at [Sean Boyce]’s guide from 2019.

The Last Instrument To Get Auto-Tuned

July 30, 2024 by 14 Comments

Various decades have their musical signature, like the excessive use of synthesizers and hairspray in the 1980s pop music scene. Likewise, the early 2010s was marked by a fairly extreme use of autotune, a technology that allows sounds, especially vocals, to be shifted to precise pitches regardless of the pitch of the original source. In this dark era, a wide swath of instruments and voices on the charts were auto-tuned at some point, although we don’t remember this iconic instrument ever being featured among the annals of pitch-shifted pop music.

The auto-tuned kazoo created by [Guy Dupont] does its pitch corrections on-the-fly thanks to a built-in ESP-32-S3 microcontroller which, through a microphone inside the kazoo, listens for note of the musician’s hum and corrects it to the closest correctly pitched note. Once it identifies the note it outputs a kazoo-like pitch-corrected note from a small speaker, also hidden inside the instrument. It does this fast enough for live performances using the YIN fundamental frequency estimation algorithm. Not only can the kazoo be played directly, but thanks to the implementation of MIDI it can be used to control other synthesizers or be played through other means as a stand-alone synthesizer.

Much like the 80s, where the use of synthesizers relaxed from excessive use on nearly every instrument on every track throughout the decade to a more restrained use as the decade faded, so has autotune been toned down in most music to be more subtly applied. But like our enjoyment of heavily synthesized tunes outside the 80s like those by Daft Punk or The Weeknd, we can also appreciate something heavily auto-tuned outside of the 2010s like a stylized kazoo or a T-Pain-style guitar effects pedal.

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