The Music Of The Sea

December 22, 2025 by Bryan Cockfield 8 Comments

For how crucial whales have been for humanity, from their harvest for meat and oil to their future use of saving the world from a space probe, humans knew very little about them until surprisingly recently. Most people, even in Herman Melville’s time, considered whales to be fish, and it wasn’t until humans went looking for submarines in the mid-1900s that we started to understand the complexities of their songs. And you don’t have to be a submarine pilot to listen now, either; all you need is something like these homemade hydraphones.

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A Heavily Modified Rivian Attempts The Cannonball Run

December 21, 2025 by Bryan Cockfield 59 Comments

There are few things more American than driving a car really fast in a straight line. Occasionally, the cars will make a few left turns, but otherwise, this is the pinnacle of American motorsport. And there’s no longer, straighter line than that from New York to Los Angeles, a time trial of sorts called the Cannonball Run, where drivers compete (in an extra-legal fashion) to see who can drive the fastest between these two cities. Generally, the cars are heavily modified with huge fuel tanks and a large amount of electronics to alert the drivers to the presence of law enforcement, but until now, no one has tried this race with an EV specifically modified for this task.

The vehicle used for this trial was a Rivian electric truck, chosen for a number of reasons. Primarily, [Ryan], the project’s mastermind, needed something that could hold a significant amount of extra batteries. The truck also runs software that makes it much more accepting of and capable of using an extra battery pack than other models. The extra batteries are also from Rivians that were scrapped after crash tests. The team disassembled two of these packs to cobble together a custom pack that fits in the bed of the truck (with the tonneau closed), which more than doubles the energy-carrying capacity of the truck.

Of course, for a time trial like this, an EV’s main weakness is going to come from charging times. [Ryan] and his team figured out a way to charge the truck’s main battery at one charging stall while charging the battery in the bed at a second stall, which combines for about a half megawatt of power consumption when it’s all working properly and minimizes charging time while maximizing energy intake. The other major factor for fast charging the battery in the bed was cooling, and rather than try to tie this system in with the truck’s, the team realized that using an ice water bath during the charge cycle would work well enough as long as there was a lead support vehicle ready to go at each charging stop with bags of ice on hand.

Although the weather and a few issues with the double-charging system stopped the team from completing this run, they hope to make a second attempt and finish it very soon. They should be able to smash the EV record, currently held by an unmodified Porsche, thanks to these modifications. In the meantime, though, there are plenty of other uses for EV batteries from wrecked vehicles that go beyond simple transportation.

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Need For Speed Map IRL

December 14, 2025 by Bryan Cockfield 18 Comments

When driving around in video games, whether racing games like Mario Kart or open-world games like GTA, the game often displays a mini map in the corner of the screen that shows where the vehicle is in relation to the rest of the playable area. This idea goes back well before the first in-vehicle GPS systems, and although these real-world mini maps are commonplace now, they don’t have the same feel as the mini maps from retro video games. [Garage Tinkering] set out to solve this problem, and do it on minimal hardware.

Before getting to the hardware, though, the map itself needed to be created. [Garage Tinkering] is modeling his mini map on Need For Speed: Underground 2, including layers and waypoints. Through a combination of various open information sources he was able to put together an entire map of the UK and code it for main roads, side roads, waterways, and woodlands, as well as adding in waypoints like car parks, gas/petrol stations, and train stations, and coding their colors and gradients to match that of his favorite retro racing game.

To get this huge and detailed map onto small hardware isn’t an easy task, though. He’s using an ESP32 with a built-in circular screen, which means it can’t store the whole map at once. Instead, the map is split into a grid, each associated with a latitude and longitude, and only the grids that are needed are loaded at any one time. The major concession made for the sake of the hardware was to forgo rotating the grid squares to keep the car icon pointed “up”. Rotating the grids took too much processing power and made the map updates jittery, so instead, the map stays pointed north, and the car icon rotates. This isn’t completely faithful to the game, but it looks much better on this hardware.

The last step was to actually wire it all up, get real GPS data from a receiver, and fit it into the car for real-world use. [Garage Tinkering] has a 350Z that this is going into, which is also period-correct to recreate the aesthetics of this video game. Everything works as expected and loads smoothly, which probably shouldn’t be a surprise given how much time he spent working on the programming. If you’d rather take real-world data into a video game instead of video game data into the real world, we have also seen builds that do things like take Open Street Map data into Minecraft.

Thanks to [Keith] for the tip!

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Extremely Rare Electric Piano Restoration

December 11, 2025 by Bryan Cockfield 13 Comments

Not only are pianos beautiful musical instruments that have stood the test of many centuries of time, they’re also incredible machines. Unfortunately, all machines wear out over time, which means it’s often not feasible to restore every old piano we might come across. But a few are worth the trouble, and [Emma] had just such a unique machine roll into her shop recently.

What makes this instrument so unique is that it’s among the first electric pianos to be created, and one of only three known of this particular model that survive to the present day. This is a Vivi-Tone Clavier piano which dates to the early 1930s. In an earlier video she discusses more details of its inner workings, but essentially it uses electromagnetic pickups like a guitar to detect vibrations in plucked metal reeds.

To begin the restoration, [Emma] removes the action and then lifts out all of the keys from the key bed. This instrument is almost a century old so it was quite dirty and needed to be cleaned. The key pins are lubricated, then the keys are adjusted so that they all return after being pressed. From there the keys are all adjusted so that they are square and even with each other. With the keys mostly in order, her attention turns to the action where all of the plucking mechanisms can be filed, and other adjustments made. The last step was perhaps the most tedious, which is “tuning” the piano by adjusting the pluckers so that all of the keys produce a similar amount or volume of sound, and then adding some solder to the reeds that were slightly out of tune.

With all of those steps completed, the piano is back in working order, although [Emma] notes that since these machines were so rare and produced so long ago there’s no real way to know if the restoration sounds like what it would have when it was new. This is actually a similar problem we’ve seen before on this build that hoped to model the sound of another electric instrument from this era called the Luminaphone.

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Off-Grid, Small-Scale Payment System

December 5, 2025 by Bryan Cockfield 27 Comments

An effective currency needs to be widely accepted, easy to use, and stable in value. By now most of us have recognized that cryptocurrencies fail at all three things, despite lofty ideals revolving around decentralization, transparency, and trust. But that doesn’t mean that all digital currencies or payment systems are doomed to failure. [Roni] has been working on an off-grid digital payment node called Meshtbank, which works on a much smaller scale and could be a way to let a much smaller community set up a basic banking system.

The node uses Meshtastic as its backbone, letting the payment system use the same long-range low-power system that has gotten popular in recent years for enabling simple but reliable off-grid communications for a local area. With Meshtbank running on one of the nodes in the network, accounts can be created, balances reported, and digital currency exchanged using the Meshtastic messaging protocols. The ledger is also recorded, allowing transaction histories to be viewed as well.

A system like this could have great value anywhere barter-style systems exist, or could be used for community credits, festival credits, or any place that needs to track off-grid local transactions. As a thought experiment or proof of concept it shows that this is at least possible. It does have a few weaknesses though — Meshtastic isn’t as secure as modern banking might require, and the system also requires trust in an administrator. But it is one of the more unique uses we’ve seen for this communications protocol, right up there with a Meshtastic-enabled possum trap.

An Introduction To Analog Filtering

December 4, 2025 by Bryan Cockfield 8 Comments

One of the major difficulties in studying electricity, especially when compared to many other physical phenomena, is that it cannot be observed directly by human senses. We can manipulate it to perform various tasks and see its effects indirectly, like the ionized channels formed during lightning strikes or the resistive heating of objects, but its underlying behavior is largely hidden from view. Even mathematical descriptions can quickly become complex and counter-intuitive, obscured behind layers of math and theory. Still, [lcamtuf] has made some strides in demystifying aspects of electricity in this introduction to analog filters.

The discussion on analog filters looks at a few straightforward examples first. Starting with an resistor-capacitor (RC) filter, [lcamtuf] explains it by breaking its behavior down into steps of how the circuit behaves over time. Starting with a DC source and no load, and then removing the resistor to show just the behavior of a capacitor, shows the basics of this circuit from various perspectives. From there it moves into how it behaves when exposed to a sine wave instead of a DC source, which is key to understanding its behavior in arbitrary analog environments such as those involved in audio applications.

There’s some math underlying all of these explanations, of course, but it’s not overwhelming like a third-year electrical engineering course might be. For anyone looking to get into signal processing or even just building a really nice set of speakers for their home theater, this is an excellent primer. We’ve seen some other demonstrations of filtering data as well, like this one which demonstrates basic filtering using a microcontroller.

Ride On With FOSS And GoldenCheetah

December 3, 2025 by Bryan Cockfield 4 Comments

If you exclude certain companies like Peloton, the world of cycling technology is surprisingly open. It’s not perfect by any means, but there are enough open or open-ish standards for many different pieces of technology from different brands to interoperate with each other, from sensors and bike computers and even indoor trainers to some extent. This has also made it possible for open source software to exist in this realm as well, and the GoldenCheetah project has jumped in for all of us who value FOSS and also like to ride various bicycles from time to time.

GoldenCheetah focuses on gathering data from power meters, allowing cyclists to record their rides and save them in order to keep track of their training performance over time. It works well with sensors that use the ANT+ protocol, and once it has that data it can provide advanced analytics such as power curves, critical power modeling, and detailed charts for power, heart rate, and cadence. It can display and record live indoor-training data, and in some situations it can even run interval workouts, although not every indoor trainer is supported. There are no social features, subscriptions, or cloud requirements which can be refreshing in the modern world, but is a bit of a downside if you’re used to riding with your friends in something like Zwift.

All in all, though, it’s an impressive bit of software that encourages at least one realm of consumer electronics to stay more open, especially if those using bike sensors, computers, and trainers pick ones that are more open and avoid those that are proprietary, even if they don’t plan to use GoldenCheetah exclusively. And if you were wondering about the ANT+ protocol mentioned earlier, it’s actually used for many more things that just intra-bike wireless communications.