Transportation Hacks

1545 Articles

Choosing The Right Battery For Your Electric Vehicle Build

January 7, 2020 by 43 Comments

Many a hacker has looked at their scooter, bike, or skateboard, and decided that it would be even better if only it had a motor on it. Setting out to electrify one’s personal transport can be an exciting and productive journey, and one that promises to teach many lessons about mechanical and electronic engineering. Fundamentally, the key to any build is the battery, which has the utmost say in terms of your vehicle’s performance and range. To help out, we’ve prepared a useful guide on selecting the right battery for your needs.

One Chemistry To Rule Them All

Batteries come in all shapes and sizes, and a variety of different chemistries that all have their own unique properties and applications. When it comes to small electric vehicles, it’s desirable to have a battery with a low weight, compact size, plenty of current delivery for quick acceleration, and high capacity for long range.

30 years ago, options were limited to lead acid, nickel cadmium, and nickel metal hydride batteries. These were heavy, with low current output, poor capacity, and incredibly slow charge times. Thankfully, lithium polymer batteries have come along in the meantime and are more capable across the board. Offering huge discharge rates, fast charging, light weight and high capacity, they’re undeniably the ultimate choice for a high performance electric vehicle. They’re also wildly popular, and thus cheap, too!

There are some hangups, however. It’s important to keep all the cells in a pack at the same voltage in order to avoid cells back-charging each other. This can cause damage to the pack, or even explosions or fire. Maintaining the battery voltages to avoid this is called “balancing”. It can be handled in various ways, depending on the exact style of battery you’re using, as we’ll cover later.

Additionally, lithium batteries do not like being over-discharged. As a rule of thumb, it’s a good idea not to let your batteries drop below 3.0 V per cell. Failure to keep this in check can lead to ruining a pack, hurting its maximum capacity and ability to deliver current.

There are thankfully ways around these issues, and which ones you use depends on the battery you choose for your application. Continue reading “Choosing The Right Battery For Your Electric Vehicle Build” →

DMCA-Locked Tractors Make Decades-Old Machines The New Hotness

January 7, 2020 by 125 Comments

It’s fair to say that the hearts and minds of Hackaday readers lie closer to the technology centres of Shenzhen or Silicon Valley than they do to the soybean fields of Minnesota. The common link is the desire to actually own the hardware we buy. Among those working the soil there has been a surge in demand (and consequently a huge price rise) in 40-year-old tractors.

Second-hand farm machinery prices have made their way to the pages of Hackaday due to an ongoing battle between farmers and agricultural machinery manufacturers over who has the right to repair and maintain their tractors. The industry giant John Deere in particular uses the DMCA and end-user licensing agreements to keep all maintenance in the hands of their very expensive agents. It’s a battle we’ve reported on before, and continues to play out across the farmland of America, this time on the secondary market. Older models continue to deliver the freedom for owners to make repairs themselves, and the relative simplicity of the machines tends to make those repairs less costly overall.

Tractors built in the 1970s and 80s continue to be reliable and have the added perk of predating the digital shackles of the modern era. Aged-but-maintainable machinery is now the sweetheart of farm sales. It confirms a trend I’ve heard of anecdotally for a few years now, that relatively new tractors can be worth less than their older DMCA-free stablemates, and it’s something that I hope will also be noticed in the boardrooms. Perhaps this consumer rebellion can succeed against the DMCA where decades of activism and lobbying have evidently failed.

They just don’t build ’em like they used to.

[Image Source: John Deere 2850 by Raf24 CC-BY-SA 3.0]

[Via Hacker News]

Steampunk Motorcycle Runs On Compressed Air, Is Pure Hacking Art

January 6, 2020 by 27 Comments

Sometimes it’s ok to sacrifice some practicality for aesthetics, especially for passion projects. Falling solidly in this category is [Peter Forsberg]’s beautiful, barely functional steam punk motorcycle. If this isn’t hacker art, then we don’t know what is.

The most eye-catching part of the motorcycle is the engine and drive train, with most of the mechanical components visible. The cylinders are clear glass tubes with custom pistons, seals, valves and push rods. The crank mechanism is from an old Harley and is mounted inside a piece of stainless steel pipe. Because it runs on compressed air it cools down instead of heating up, so an oil system is not needed.

For steering, the entire front of the bike swings side to side on hinges in the middle of the frame, which is quite tricky to ride with a top speed that’s just above walking speed. It can run for about 3-5 minutes on a tank, so the [Peter] mounted a big three-minute hour glass in the frame. The engine is fed from an external air tank, which he wears on his back; he admits it’s borderline torture to carry the thing for any length of time. He plans to build a side-car to house a much larger tank to extend range and improve riding comfort.

[Peter] admits that it isn’t very good as a motorcycle, but the amount of creativity and resourcefulness required to make it functional at all is the mark of a true mechanical hacker. We look forward to seeing it in its final form.

Continue reading “Steampunk Motorcycle Runs On Compressed Air, Is Pure Hacking Art” →

Reducing The Risk Of Flying With Hydrogen Fuels

January 1, 2020 by 91 Comments

Flight shaming is the hot new thing where people who take more than a handful of trips on an airplane per year are ridiculed for the environmental impact of their travels. It’s one strategy for making flying more sustainable, but it’s simply not viable for ultimately reducing the carbon impact that the airline industries have on the environment.

Electric planes are an interesting place to look for answers. Though carbon-free long haul travel is possible, it’s not a reality for most situations in which people travel today. Current battery technology can’t get anywhere near the energy density of fossil fuels and larger batteries aren’t an option since every pound matters when designing aircraft.

Even with land travel and electric grids improving in their use of renewables and electric power, aviation tends to be difficult to power with anything other than hydrocarbons. Student engineers in the AeroDelft program in the Netherlands have created Project Phoenix to develop an aircraft powered by a liquid hydrogen fuel cell, producing a primary emission of water vapor. So it is an electric plane, but leverages the energy density of hydrocarbons to get around the battery weight problem.

While the project may seem like an enormous reach peppered with potential safety hazards, redundant safety features are used such as sensors and vents in case of a hydrogen leakage, as well as an electric battery in case of failure. Hydrogen produced three times more energy per unit than kerosene, but is six times the volume in gas form and requires cumbersome compression tanks.

Even though hydrogen fuel only produces water vapor as a byproduct, it can still cause greenhouse effects if it is released too high and creates clouds. The team is exploring storage tanks for slow release of the water vapor at more optimal altitudes. On top of that, most hydrogen is produced using steam methane reforming (SMR), creating up to 150g of greenhouse gases per kWh, and electrolysis tends to be more costly and rarely carbon neutral. Alternatives such as solar power, biofuels, and electric power are looking to make headwind as well, but the technology is still far from perfected.

While it’s difficult to predict the success of the project so early on, the idea of reducing risk in hydrogen fuels may not be limited to a handful of companies for very long.

Continue reading “Reducing The Risk Of Flying With Hydrogen Fuels” →

At Three Grand A Tail Light, There’s An Opportunity For A Hacker

December 29, 2019 by 65 Comments

It can be amusing sometimes, to read an incredulous reaction from outside our community to something that would be bread-and-butter in most hackerspaces. Take the sorry saga of the Cadillac XLR tail light, as reported by Jalopnik. This car was a more-expensive Corvette with a bit of lard around its midriff, and could appear a tempting pick for a bit of inexpensive luxury rubber-burning were it not for the revelation that a replacement second-hand tail light for one of these roadsters can set you back as much as three grand. The trusty auto on the drive outside where this is being written cost around a tenth that sum, so what on earth is up? Is it because a Caddy carries some cachet, or is something else at play?

It appears that the problem lies in the light’s design. It’s an LED unit, with surface mount parts and a set of fragile internal PCBs that are coated in something that makes reworking them a challenge. On top of that, the unit is bonded together, and instead of being a traditional on-off tail light it’s a microprocessor-controlled device that gets its orders digitally. This is all too much for XLR owners and for the Jalopnik hacks, who castigate General Motors for woefully inadequate design and bemoan the lack of alternatives to the crazy-expensive lights, but can’t offer an alternative.

Reading about the problem from a hardware hacker perspective they are right to censure the motor manufacturer for an appalling product, but is there really nothing that can be done? Making off-the-shelf microcontroller boards light up LEDs is an elementary introduction project for our community, and having the same boards talk to a car’s computer via CAN is something of a done deal. Add in LED strips and 3D printing to create a new backing for the tail light lens, and instead of something impossibly futuristic, you’re doing nothing that couldn’t be found in hackerspaces five years ago.

So what’s to be learned from the Cadillac XLR tail light? First of all, there’s scope for an enterprising hacker to make a killing on a repair kit for owners faced with a three grand bill. Then, there’s another opportunity for us to be acquainted with the reality that the rest of the world hasn’t quite caught up with repair culture as we might imagine. And finally there’s the hope that a badly designed automotive component might just be the hook by which the issue of designed-in obsolescence moves up the agenda in the public consciousness. After all, there will be other similar stories to come, and only bad publicity is likely to produce a change in behavior.

Of course, to get it really right you need a car that’s hackable in the first place. Or better still, one designed by and for hackers.

Thanks [str-alorman] for the tip.

Cadillac XLR header image:Rudolf Stricker [CC BY-SA 3.0].

Eight Motors Speed This Boat Along

December 21, 2019 by 16 Comments

Messing about in boats has always held a curious appeal for the hardware hacker. Perhaps that’s because it remains an approachable way to make something that moves under its own power with a bit of speed, and barring calamities, the worst that can happen to the unwary boater is a soaking. [NASAT Channel] is a Vietnamese hacker who is a serial producer of small motorised boats, and one of his latest is a particularly impressive example.

The boat itself is a relatively conventional expanded polystyrene hull covered with fiberglass, but the motive power is something a little special. He’s taken eight of the ubiquitous 775 DC brushed motors and used them in a star configuration with beveled gears, which in turn drives a flexible shaft which goes straight to a propeller under the craft. Each motor shares a water cooling pipe serviced by a small pump, and the drive comes from a pair of cheap PWM motor controllers. We see him zipping up and down a stretch of river next to some moored boats, and if we’re honest, we wouldn’t mind a go ourselves.

We’re not entirely convinced such a rough-and-ready eight-way gearbox will be reliable for long-term use, and we’d be interested to know just how equally so many motors are actually sharing the load. But we like it for its sheer audacity, and we think you will too. Take a look at the video below the break, and if you’re inspired then grab a hammock, some friends, and have a go.

Continue reading “Eight Motors Speed This Boat Along” →

Dashboard Dongle Teardown Reveals Hardware Needed To Bust Miles

December 16, 2019 by 43 Comments

Progress and the proliferation of computers in automotive applications have almost made the shade tree mechanic a relic of the past. Few people brave the engine compartment of any car made after 1999 or so, and fewer still dive into the space behind the dashboard. More’s the pity, because someone may be trying to turn back the odometer with one of these nefarious controller area network (CAN bus) dongles.

Sold through the usual outlets and marketed as “CAN bus filters,” [Big Clive] got a hold of one removed from a 2015 Mercedes E-Class sedan, where a mechanic had found it installed between the instrument cluster and the OEM wiring harness. When the dongle was removed, the odometer instantly added 40,000 kilometers to its total, betraying someone’s dishonesty.

[Big Clive]’s subsequent teardown of the unit showed that remarkably little is needed to spoof a CAN bus odometer. The board has little more than an STM32F microcontroller, a pair of CAN bus transceiver chips, and some support circuitry like voltage regulators. Attached to a wiring harness that passes through most of the lines from the instrument cluster unmolested while picking off the CAN bus lines, the device can trick the dashboard display into showing whatever number it wants. The really interesting bit would be the code, into which [Clive] does not delve. That’s a pity, but as he points out, it’s likely the designers set the lock bit on the microcontroller to cover their tracks. There’s no honor among thieves.

We found this plunge into the dark recesses of the automotive world fascinating, and [Big Clive]’s tutelage top-notch as always. If you need to get up to speed on CAN bus basics, check out [Eric Evenchick]’s series on automotive network hacking.

Continue reading “Dashboard Dongle Teardown Reveals Hardware Needed To Bust Miles” →