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A grey car sits in the background out of focus, its front facing the camera. It sits over an asphalt roadway with a metal rail extending from the foreground to behind the car in the distance. The rail has a two parallel slots and screws surrounding the slots running down the rail.

What Happened To Sweden’s Slot Car EV Road?

March 1, 2023 by 60 Comments

Many EVs can charge 80% of their battery in a matter of minutes, but for some applications range anxiety and charge time are still a concern. One possible solution is an embedded electrical rail in the road like the [eRoadArlanda] that Sweden unveiled in 2016.

Overhead electrical wires like those used in trolleys have been around since the 1800s, and there have been some tests with inductive coils in the roadway, but the 2 km [eRoadArlanda] takes the concept of the slot car to the next level. The top of the rail is grounded while the live conductor is kept well underground beneath the two parallel slots. Power is only delivered when a vehicle passes over the rail with a retractable contactor, reducing danger for pedestrians, animals, and other vehicles.

One of the big advantages of this technology being in the road bed is that both passenger and commercial vehicles could use it unlike an overhead wire system that would require some seriously tall pantographs for your family car. Testing over several Swedish winters shows that the system can shed snow and ice as well as rain and other road debris.

Unfortunately, the project’s website has gone dark, and the project manager didn’t respond when we reached out for comment. If there are any readers in Sweden with an update, let us know in the comments!

We’ve covered both overhead wire and embedded inductive coil power systems here before if you’re interested in EV driving with (virtually) unlimited range.

Continue reading “What Happened To Sweden’s Slot Car EV Road?” →

Repurposing Old Smartphones: When Reusing Makes More Sense Than Recycling

February 28, 2023 by 89 Comments

When looking at the specifications of smartphones that have been released over the past years, it’s remarkable to see how aspects like CPU cores, clockspeeds and GPU performance have improved during this time, with even new budget smartphones offering a lot of computing power, as well as a smattering of sensors. Perhaps even more remarkable is that of the approximately 1.5 billion smartphones sold each year, many will be discarded again after a mere two years of use. This seems rather wasteful, and a recent paper by Jennifer Switzer and colleagues proposes that a so-called Computational Carbon Intensity (CCI) metric should be used to determine when it makes more sense to recycle a device than to keep using it.

What complicates the decision of when it makes more sense to reuse than recycle is that there are many ways to define when a device is no longer ‘fit for purpose’. It could be argued that the average smartphone is still more than good enough after two years to be continued as a smartphone for another few years at least, or at least until the manufacturer stops supplying updates. Beyond the use as a smartphone, they’re still devices with a screen, WiFi connection and a capable processor, which should make it suitable for a myriad of roles.

Unfortunately, as we have seen with the disaster that was Samsung’s ‘upcycling’ concept a few years ago, or Google’s defunct Project Ara, as promising as the whole idea of ‘reuse, upcycle, recycle’ sounds, establishing an industry standard here is frustratingly complicated. Worse, over the years smartphones have become ever more sealed-up, glued-together devices that complicate the ‘reuse’ narrative.

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Low Power Challenge: Keep Plants Green And Clean With E-Paper Smart Tags

February 25, 2023 by 7 Comments

There are plenty of reasons to devote oneself to the care of houseplants — after all, a room full of bright, glossy-leaved plants can be a joy to behold, and that’s not even one of the more tangible benefits they bring. But as any green thumb knows, there’s a fine line between a healthy, vibrant plant and one that’s soon to give up the ghost.

If your thumb tends less toward green and more toward the brown and crusty side of things, something like [Jon]’s Smart Plant system might be just the thing for you. These low-power plant tags are built around increasingly ubiquitous e-Paper displays, like the kind you might find in a retail shelf price tag system. The current version of [Jon]’s tags uses a Waveshare 2.9″ tricolor display and a PCB with capacitive probes that stick into the plant’s soil. An ESP32-S lives on the top section of the PCB, along with a 1,000 mAh LiPo pack that’s charged off USB-C. The design includes an optional solar panel for keeping the battery topped off, which may or may not help depending on the plant’s place in your personal jungle.

In addition to the soil moisture sensor, the Smart Tag has an ambient temperature and humidity sensor and a light sensor — everything to keep your plant happy. The power-hungry sensors are only powered on when the Smart Tag pops out of deep sleep; this gives and estimated five to six weeks runtime between charges, without solar charging of course. The e-Paper display shows custom graphics of the plant’s current environmental state, and the same data is also available via Home Assistant thanks to the ESPHome firmware.

These are nice-looking plant tags that can really pull a lot of weight in keeping plants healthy. Check out the other offerings in our Low Power Challenge Contest, and maybe get an entry together yourself.

2023 Hackaday.io Low-Power Challenge

Methane Pyrolysis: Producing Green Hydrogen Without Carbon Emissions

February 13, 2023 by 52 Comments

Generally, when we talk about the production of hydrogen, the discussion is about either electrolysis of water into oxygen and hydrogen, or steam methane reforming (SMR). Although electrolysis is often mentioned – as it can create hydrogen using nothing but water and electricity – SMR is by far the most common source of hydrogen. Much of this is due to the low cost and high efficiency of SMR, but a major disadvantage of SMR is that :slider

large amounts of carbon dioxide are released, which offsets some of the benefits of using hydrogen as a fuel in the first place.

Although capturing this CO2 can be considered as a potential solution here, methane pyrolysis is a newer method that promises to offer the same benefits as SMR while also producing hydrogen and carbon, rather than CO2. With the many uses for hydrogen in industrial applications and other fields, such as the manufacturing of fertilizer, a direct replacement for SMR that produces green hydrogen would seem almost too good to be true.

What precisely is this methane pyrolysis, and what can be expect from it the coming years?

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A white longtail cargo bike sits on grass with fenced-in planters behind it. The bike has a basket made of black metal tubes on the front and a passenger compartment behind the rider seat for children made of similar black metal tubes. A white canopy is above the passenger compartment and a solar panel sits atop the canopy.

Solar Powered E-bike Replaces Car Trips

February 7, 2023 by 20 Comments

E-bikes can replace car trips for some people, and adding a solar panel can make the fun last longer. [Luke] did some heavy modifications to his RadWagon to make it better, stronger, and faster than it was before.

The first step was replacing the stock 750 W controller with a 1500 W model to give the motor twice the power. [Luke] plans to replace the motor if it gets fried pushing too much juice, but is planning on just being careful for now. To stop this super-powered ride, he swapped the stock mechanical discs out for a hydraulic set which should be more reliable, especially when loading down this cargo bike.

On top of these performance enhancements, he also added a 50 W solar panel and maximum power point tracking (MPPT) charge controller to give the bike a potential 50% charge every day. Along with the OEM kid carrier and roof, this bike can haul kids and groceries while laughing at any hills that might come its way.

Checkout this other solar e-bike or this one making a trip around the world for more fun in the sun.

China’s New 100 MPH Train Runs On Hydrogen And Supercaps

February 2, 2023 by 83 Comments

Electric cars are very much en vogue right now, as the world tries to clean up on emissions and transition to a more sustainable future. However, these vehicles require huge batteries as it is. For heavier-duty applications like trucks and trains, batteries simply won’t cut the mustard.

Normally, the solution for electrifying railways is to simply string up some wires and call it a day. China is trying an alternative solution, though, in the form of a hydrogen-powered train full of supercapacitors.

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Comparing Cheap Capacitative Soil Moisture Sensors With Commercial Sensors

February 1, 2023 by 40 Comments

When your residence has soil moisture sensors embedded that were dictated by your friendly neighborhood HoA, you may start asking questions about the system used. That’s what [Modest Maker] did and the resulting findings along with an attempt to beat the commercial system with some cheap capacitive sensors, are covered  in a recent video that’s also embedded below. Part of the motivation here was that the commercial system in the community was not clearly installed properly.

To make a long story short, the commercial system by Hunter (Soil-Clik) appears to be a tensiometer-based system that uses the pressure produced by moisture intrusion into the measurement column. This translates to how easy it is for plant roots to extract water, depending on the soil type. [Modest Maker] had to first dodge the broken-by-design capacitive sensors that are available everywhere, but after that was able to cobble together a measurement system that he hopes will allow him to validate the commercial system’s installation.

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