Keeping Streets Ice-Free With The Raspberry Pi

April 17, 2018 by Tom Nardi 33 Comments

[Revanth Kailashnath] writes in to tell us about an interesting project he and his team have been working on for their “Real Time Embedded Programming” class at the University of Glasgow. Intended to combat the harsh and dangerous winters in Glasgow, their system uses a Raspberry Pi and a suite of sensors to automatically deploy a brine solution to streets and sidewalks. While the project is still only a proof of concept and hasn’t been deployed, the work the team has done so far runs the gamut from developing their own PCBs to creating a web-based user interface.

The core idea is simple. If the conditions are right for ice to form, spray salt water. Using salt water is a cheap and safe way of clearing and preventing ice as it simply drops the temperature at which water freezes. The end result is that the ice won’t form until it gets down to 10F (-12C) or so. Not a perfect solution, but it can definitely help. Of course, you don’t want to spray people with salt water as they pass by, so there’s a bit more to it than that.

Using the venerable DHT22 sensor the team can get the current temperature and humidity, which allows them to determine when it’s time to start spraying. But to prevent any wet and angry pedestrians, a HC-SR501 PIR motion sensor is used. If the system sees motion it will stop for a while to let the activity quiet down.

Monitoring the sensors and controlling the pump is done by a daemon written in C++, which also logs data to an SQL database, which in turn feeds their PHP web interface. In the video after the break, [Revanth] demonstrates how the system is constantly making decisions based on the input of the various sensors. Environmental data and motion is analysed every few seconds to provide a real-time solution.

We’ve covered a few projects aimed at melting ice and snow by heating concrete, but it’s interesting to see a “smart” approach to this common winter annoyance.

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Self-Driven: Uber And Tesla

April 2, 2018 by Elliot Williams 164 Comments

Self-driving cars have been in the news a lot in the past two weeks. Uber’s self-driving taxi hit and killed a pedestrian on March 18, and just a few days later a Tesla running in “autopilot” mode slammed into a road barrier at full speed, killing the driver. In both cases, there was a human driver who was supposed to be watching over the shoulder of the machine, but in the Uber case the driver appears to have been distracted and in the Tesla case, the driver had hands off the steering wheel for six seconds prior to the crash. How safe are self-driving cars?

Trick question! Neither of these cars were “self-driving” in at least one sense: both had a person behind the wheel who was ultimately responsible for piloting the vehicle. The Uber and Tesla driving systems aren’t even comparable. The Uber taxi does routing and planning, knows the speed limit, and should be able to see red traffic lights and stop at them (more on this below!). The Tesla “Autopilot” system is really just the combination of adaptive cruise control and lane-holding subsystems, which isn’t even enough to get it classified as autonomous in the state of California. Indeed, it’s a failure of the people behind the wheels, and the failure to properly train those people, that make the pilot-and-self-driving-car combination more dangerous than a human driver alone would be.

A self-driving Uber Volvo XC90, San Francisco.

You could still imagine wanting to dig into the numbers for self-driving cars’ safety records, even though they’re heterogeneous and have people playing the mechanical turk. If you did, you’d be sorely disappointed. None of the manufacturers publish any of their data publicly when they don’t have to. Indeed, our glimpses into data on autonomous vehicles from these companies come from two sources: internal documents that get leaked to the press and carefully selected statistics from the firms’ PR departments. The state of California, which requires the most rigorous documentation of autonomous vehicles anywhere, is another source, but because Tesla’s car isn’t autonomous, and because Uber refused to admit that its car is autonomous to the California DMV, we have no extra insight into these two vehicle platforms.

Nonetheless, Tesla’s Autopilot has three fatalities now, and all have one thing in common — all three drivers trusted the lane-holding feature well enough to not take control of the wheel in the last few seconds of their lives. With Uber, there’s very little autonomous vehicle performance history, but there are leaked documents and a pattern that makes Uber look like a risk-taking scofflaw with sub-par technology that has a vested interest to make it look better than it is. That these vehicles are being let loose on public roads, without extra oversight and with other traffic participants as safety guinea pigs, is giving the self-driving car industry and ideal a black eye.

If Tesla’s and Uber’s car technologies are very dissimilar, the companies have something in common. They are both “disruptive” companies with mavericks at the helm that see their fates hinging on getting to a widespread deployment of self-driving technology. But what differentiates Uber and Tesla from Google and GM most is, ironically, their use of essentially untrained test pilots in their vehicles: Tesla’s in the form of consumers, and Uber’s in the form of taxi drivers with very little specific autonomous-vehicle training. What caused the Tesla and Uber accidents may have a lot more to do with human factors than self-driving technology per se.

You can see we’ve got a lot of ground to cover. Read on!

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Pavement Projection Provides Better Bicycle Visibility At Night

April 2, 2018 by Dan Maloney 67 Comments

Few would question the health benefits of ditching the car in favor of a bicycle ride to work — it’s good for the body, and it can be a refreshing relief from rat race commuting. But it’s not without its perils, especially when one works late and returns after dark. Most car versus bicycle accidents occur in the early evening, and most are attributed to drivers just not seeing cyclists in the waning light of day.

To decrease his odds of becoming a statistics and increase his time on two wheels, [Dave Schneider] decided to build a better bike light. Concerned mainly with getting clipped from the rear, and having discounted the commercially available rear-mounted blinkenlights and wheel-mounted persistence of vision displays as insufficiently visible, [Dave] looked for ways to give drivers as many cues as possible. Noticing that his POV light cast a nice ground effect, he came up with a pavement projecting display using four flashlights. The red LED lights are arranged to flash onto the roadway in sequence, using the bike’s motion to sweep out a sort of POV “bumper” to guide motorists around the bike. The flashlight batteries were replaced with wooden plugs wired to the Li-ion battery pack and DC-DC converter in the saddle bag, with an Arduino tasked with the flashing duty.

The picture above shows a long exposure of the lights in action, and it looks very effective. We can’t help but think of ways to improve this: perhaps one flashlight with a servo-controlled mirror? Or variable flashing frequency based on speed? Maybe moving the pavement projection up front for a head-down display would be a nice addition too.

Traction Control Gets More Power To The Road For Tot-Sized Lamborghini

March 18, 2018 by Dan Maloney 21 Comments

We’ve all heard the complaints from oldsters: “Cars used to be so simple that all you needed to fix them was a couple of wrenches and a rag. Now, you need a computer science degree to even pop the hood!” It’s true to some extent, but such complexity is the cost of progress in the name of safety and efficiency. And now it seems this complexity is coming way down-market, with this traction control system for a Power Wheels Lamborghini.

While not exactly an entry-level model from the Power Wheels line of toddler transportation, the pint-sized Lamborghini Aventador [Jason] bought for his son had a few issues. Straight from the factory, its 6-volt drivetrain was a little anemic, with little of the neck-snapping acceleration characteristic of an electric drive. [Jason] opted to replace the existing 6-volt drive with a 12-volt motor and battery while keeping the original 6-volt controller in place. The resulting rat’s nest of relays was unsightly but sufficient to see a four-fold increase in top speed.

With all that raw power sent to only one wheel, though, the Lambo was prone to spinouts. [Jason] countered this with a traction control system using optical encoders on each of the rear wheels. A NodeMCU senses speed differences between the wheels and controls the motor through an H-bridge to limit slipping. As a bonus, a smartphone app can connect to the Node for in-flight telemetry. Check out the build and the car being put through its paces by the young [Mr. Steal Your Girl] in the video below.

The Power Wheels platform is infinitely hackable – from repairs to restorations to enhancements of questionable sanity, it seems like there’s nothing you can’t do with these little electric vehicles.

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The Pontoon Bridge Being Floated As An NYC Transit Fix

March 8, 2018 by Alex Weinberg 96 Comments

New York City’s L train carries about 400,000 passengers a day, linking Manhattan and Brooklyn and bringing passengers along 14th Street, under the East River, and through the neighborhoods of Williamsburg, Bushwick, Ridgewood, Brownsville, and Canarsie. About 225,000 of these passengers pass through the Canarsie Tunnel, a two-tube cast iron rail tunnel built below the East River between Manhattan and Brooklyn in 1924. Like many other New York City road and subway tunnels, the Canarsie Tunnel was badly damaged when Hurricane Sandy’s storm surge inundated the tubes with million of gallons of salt water. Six years later, the impending closure of the tunnel is motivating New Yorkers to develop their own ambitious infrastructure ideas.

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Retrotechtacular: A Very British MagLev

March 6, 2018 by Jenny List 54 Comments

When we look back to the 1970s it is often in a light of somehow a time before technology, a time when analogue was still king, motor vehicles had carburettors, and telephones still had rotary dials.

In fact the decade had a keen sense of being on the threshold of an exciting future, one of supersonic air travel, and holidays in space. Some of the ideas that were mainstream in those heady days didn’t make it as far as the 1980s, but wouldn’t look out of place in 2018.

The unlikely setting for todays Retrotechtacular piece is the Bedford Levels, part of the huge area of reclaimed farmland in the east of England known collectively as the Fens. The Old Bedford River and the New Bedford River are two straight parallel artificial waterways that bisect the lower half of the Fens for over 20 miles, and carry the flood waters of the River Ouse towards the sea. They are several hundred years old, but next to the Old Bedford River at their southern end are a few concrete remains of a much newer structure from 1970. They are all that is left of a bold experiment to create Britain’s first full-sized magnetic levitating train, an experiment which succeeded in its aim and demonstrated its train at 170 miles per hour, but was eventually canceled as part of Government budget cuts.

A track consisting of several miles of concrete beams was constructed during 1970 alongside the Old Bedford River, and on it was placed a single prototype train. There was a hangar with a crane and gantry for removing the vehicle from the track, and a selection of support and maintenance vehicles. There was an electrical pick-up alongside the track from which the train could draw its power, and the track had a low level for the hangar before rising to a higher level for most of its length.

After cancellation the track was fairly swiftly demolished, but the train itself survived. It was first moved to Cranfield University as a technology exhibit, before in more recent years being moved to the Railworld exhibit at Peterborough where it can be viewed by the general public. The dream of a British MagLev wasn’t over, but the 1980s Birmingham Airport shuttle was hardly in the same class even if it does hold the honour of being the world’s first commercial MagLev.

We have two videos for you below the break, the first is a Cambridge Archaeology documentary on the system while the second is a contemporary account of its design and construction from Imperial College. We don’t take high-speed MagLevs on our travels in 2018, but they provide a fascinating glimpse of one possible future in which we might have.

It does make one wonder: will the test tracks for Hyperloop transportation break the mold and find mainstream use or will we find ourselves 50 years from now running a Retrotechtacular on abandoned, vacuum tubes?

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SpaceX Joins In The Long History Of Catching Stuff From Space

February 26, 2018 by Tom Nardi 39 Comments

On February 22nd, a Falcon 9 rocket lifted off from Vandenberg Air Force Base in California and successfully delivered into orbit an Earth-observation satellite operated by the Spanish company Hisdesat. Compared to the media coverage received by the launch of the Tesla-laden Falcon Heavy earlier in the month, this mission got very little attention. But that’s hardly surprising. With respect to Hisdesat, the payload this time around was not terribly exciting, and even the normally dramatic landing of the Falcon 9’s first stage was skipped in favor of simply allowing the booster to crash into the ocean.

As far as SpaceX launches go, this one was about as low-key as they come. It wouldn’t be a surprise if this is the first time some readers are even hearing about it. But while it didn’t invoke the same media circus as the images of a spacesuit-wearing mannequin traveling into deep space, there was still a historic “first” performed during this mission.

In an effort to increase the re-usability of the Falcon 9 booster, SpaceX attempted to catch the payload fairing (essentially a large protective nose cone) with a huge net as it fell from space. The most interesting thing about this new chapter in the quest for a fully reusable rocket system is that while SpaceX is generally considered to be pioneers in the world of bringing hardware back from space, this particular trick dates all the way back to the 1960’s.

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