A black, rectangular box is shown, with a number of waterproof screw connectors on the front.

A Ruggedized Raspberry Pi For Sailors

September 20, 2025 by Aaron Beckendorf 6 Comments

Nautical navigation has a long history of innovation, from the compass and chronometer to today’s computer-driven autopilot systems. That said, the poor compatibility of electronics with saltwater has consequently created a need for rugged, waterproof computers, a category to which [Matti Airas] of Hat Labs has contributed with the open-source HALPI2.

Powered by the Raspberry Pi Compute Module 5, the electronics are housed in a heavy duty enclosure made of aluminium, which also serves as a heat sink, and closes with a waterproof seal. It has a wide variety of external connectors, all likewise waterproofed: power, HDMI, NMEA 2000 and NMEA 0183, Ethernet, two USB 3.0 ports, and an external WiFi or Bluetooth antenna. The external ports are plugged into the carrier board by short extension cables, and there are even more ports on the carrier board, including two HDMI connectors, two MIPI connectors, four USB ports, and a full GPIO header. The case has plugs to install additional PG7 or SP13 waterproof connectors, so if the existing external connectors aren’t enough, you can add your own.

Besides physical ruggedness, the design is also resistant to electrical damage. It can run on power in the 10-32 volt range, and is protected by a fuse. A supercapacitor bank preserves operation during a power glitch, and if the outage lasts for more than five seconds, can keep the system powered for 30-60 seconds while the operating system shuts down safely. The HALPI2 can also accept power over NMEA 2000, in which case it has the option to limit current draw to 0.9 amps.

The design was originally created to handle navigation, data logging, and other boating tasks, so it’s been configured for and tested with OpenPlotter. Its potential uses are broader than that, however, and it’s also been tested with Raspberry Pi OS for more general projects. Reading through its website, the most striking thing is how thoroughly this is documented: the site describes everything from the LED status indicators to the screws that close the housing – even a template for drilling mounting holes.

Given the quality of this project, it probably won’t surprise you to hear this isn’t [Matti]’s first piece of nautical electronics, having previously made Sailor HATs for the ESP32 and the Raspberry Pi.

This Rail Speeder Needs A Little Work

September 16, 2025 by Jenny List 28 Comments

If you take the wheels off a FIAT Punto, you might just notice that those rims fit nicely on a rail. [AT Lab] did, and the resulting build makes for a very watchable video.

Some of us have been known to spend a little too much time chasing trains, and there’s little on rails that won’t catch a railfan’s eye. That goes for rail speeders too, home constructed railcarts for exploring abandoned lines, and there are some great builds out there. We like the one in the video below the break, but we can’t help noticing a flaw which might just curtail its career.

It’s a simple enough build, a wooden chassis, a single motor and chain drive to one axle. All the wheel fittings are 3D printed, which might be a case of using the one tool you have to do everything, but seems to work. It rides well on the test track which appears to be an abandoned industrial siding, but it’s in those wheels we can see the problem and we guess that perhaps the builder is not familiar with rails. The Punto wheels have an inner rim and an outer rim, while a true rail wheel only has an inner one. There’s a good reason for this; real railways have points and other trackwork, not to mention recessed rails at road crossings or the like. We love the cart, but we’d cut those inner rims off to avoid painful derailments.

If you’re up for the ultimate railway build, take care not to go near a live line, and make sure you follow this video series.

Continue reading “This Rail Speeder Needs A Little Work” →

Making An Ultralight Helicopter

September 8, 2025 by Fenix Guthrie 38 Comments

Ultralight aviation provides an excellent pathway for those who want to fly, but don’t want to get licensed. These quite often cheap and cheerful DIY aircraft often hide some excellent engineering underneath. This is no more true than in [ultralight helicopter’s] four-year-long helicopter build saga!

While most ultralight builds are fixed-wing, a rotocraft can meet all the legal definitions of ultralight aviation. This helicopter is an excellent example of what’s possible with a lot of time and patience. The construction is largely aluminium with some stainless steel on the skids. A 64-horsepower Rotax 582UL engine powers the two-bladed main rotor and tail rotor. The drivetrain features a multi-belt engine coupler and three gearboxes to ensure correct power output to the two rotors.

Continue reading “Making An Ultralight Helicopter” →

Making The World’s Smallest E-Bike Battery

September 1, 2025 by Fenix Guthrie 25 Comments

Often times, e-bikes seek to build the biggest battery with the most range. But what if you want to take a couple lunch loops on your bike and only need 20 minutes of charge? That’s [Seth] from Berm Peak set out to find out with his minuscule Bermacell battery.

The battery is made from only 14 18650s, this tiny 52V batty is nearly as small an e-bike battery as can be made. Each cell is 3000 mAh making a total battery capacity of 156 Wh. All the cells were welded in series with an off the shelf BMS and everything was neatly packaged in an over-sized 3D printed 9V battery case. [Seth] plans to make another smaller battery with less then 100 Wh of capacity so he can take it on a plane, so stay tuned for more coverage!

Continue reading “Making The World’s Smallest E-Bike Battery” →

JuiceBox Rescue: Freeing Tethered EV Chargers From Corporate Overlords

August 27, 2025 by Maya Posch 32 Comments

The JuiceBox charger in its natural environment. (Credit: Nathan Matias)

Having a charger installed at home for your electric car is very convenient, not only for the obvious home charging, but also for having scheduling and other features built-in. Sadly, like with so many devices today, these tend to be tethered to a remote service managed by the manufacturer. In the case of the JuiceBox charger that [Nathan Matias] and many of his neighbors bought into years ago, back then it and the associated JuiceNet service was still part of a quirky startup. After the startup got snapped up by a large company, things got so bad that [Nathan] and others saw themselves required to find a way to untether their EV chargers.

The drama began back in October of last year, when the North American branch of the parent company – Enel X Way – announced that it’d shutdown operations. After backlash, the online functionality was kept alive while a buyer was sought. That’s when [Nathan] and other JuiceBox owners got an email informing them that the online service would be shutdown, severely crippling their EV chargers.

Ultimately both a software and hardware solution was developed, the former being the JuicePass Proxy project which keeps the original hardware and associated app working. The other solution is a complete brain transplant, created by the folk over at OpenEVSE, which enables interoperability with e.g. Home Assistant through standard protocols like MQTT.

Stories like these make one wonder how much of this online functionality is actually required, and how much of it just a way for manufacturers to get consumers to install a terminal in their homes for online subscription services.

Volkswagen Joins The Car-As-A-Service Movement With Its ID.3 BEV

August 19, 2025 by Maya Posch 113 Comments

More and more car manufacturers these days are becoming interested in the recurring revenue model, with Volkswagen’s ID.3 BEV being the latest to have an optional ‘motor power upgrade’ that you can pay for either monthly or with a ‘lifetime’ payment.

As the BBC reports, this option is now available in the UK, with customers offered the option to pay £16.50 per month or £165 annually, or opt to shell out £649 for what is reportedly a ‘car lifetime’ subscription.

It appears that this subscription service has been in the works for a while already, with it being offered first last year in countries like Denmark, following which it appears to be rolled out in other countries too. The software unlock changes the maximum motor output from 150 kW to 170 kW, which some users report as being noticeable.

Regardless of whether you find this to be a good deal, the concept of Car-As-A-Service (CAAS) has becoming increasingly prevalent, with the BBC article referencing BMW’s heated seats subscription and Mercedes’ acceleration subscription. Considering that all the hardware is already in the car that you purportedly purchased, this is sure to rub people the wrong way, not to mention that from a car tuning perspective this seems to suggest that third-party tuners don’t need to apply.

Thanks to [Robert Piston] for the tip.

Practical Guide To Pedal-Powered Electrical Generators

August 17, 2025 by Maya Posch 51 Comments

An adult human can produce about 100 Wh of mechanical power whilst cycling, which is a not inconsiderable amount if you can convert that to electricity with reasonable efficiency. In a recent article on EDN [T. K. Hareendran] goes over a few ways that you can turn the rotary motion of pedaling into usable electrical power.

Suggested voltage regulator for pedal-powered generator. (Credit: T. K. Hareendran, EDN)

A basic form of this is already widely deployed, in the form of a bicycle dynamo that is used to supply power to the front and rear lights. These typically put out something like 3 watts at 6 VAC, so with a simple bridge rectifier and some smoothing this can power a pretty bright LED or two. To get more out of it, you need to use a more capable generator, which can also be a brushed or brushless DC motor in a pinch, with ideally a flywheel in the whole contraption to balance out variations in the human power input.

As for the potential here, a commercial solution like the K-Tor Power Box 50 is specified for ‘greater than’ 50 Watt, with a nominal 12 VDC output. Its target market is emergency generators, with enough capability to keep phones, radios and flashlights charged. Considering the $435 asking price, there is probably quite a lot of DIY potential well within that price bracket, especially if you already have many of the requisite parts lying around.

Fortunately this is not a new idea, with us having covered using bicycles as well as gym equipment to generate electricity in the past.