RFID Lock Keeps Your Bike Safe

What do you do with an RFID chip implanted in your body? If you are [gmendez3], you build a bike lock that responds to your chip. The prototype uses MDF to create a rear wheel immobilizer. However, [gmendez3] plans on building a version using aluminum.

For the electronics, of course, there’s an Arduino. There’s also an RC522 RFID reader. We couldn’t help but think of the Keyduino for this application. When the system is locked, the Arduino drives a servo to engage the immobilizer. To free your rear wheel, simply read your implanted chip. The Arduino then commands the servo to disengage the immobilizer. You can see the system in operation in the video below.

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Hoverboards are here – If You’re Crazy Enough to Try

A new video has been stirring questions on the internet this week. It shows a test of the Flyboard Air, a device that is somewhere between a Back to the Future Hoverboard and Green Goblin’s glider. The video depicts pilot [Frank Zapata] taking off, flying around, and landing an a platform not much larger than a milk crate. Plenty of folks are calling the video a fake. After a few back of the napkin calculations though, we’re coming out to say we think it’s real. Details are few and far between, so much of the information in this article is educated guessing based upon the video.

Here’s our hypothesis: Flyboard Air is a jet powered platform with little or no built-in intelligence. Balance, stability and control are all handled by the pilot. A hand controller simply provides throttle to adjust altitude, take off, and land.

jetfeetLet’s start with the jet powered part. During the video, [Frank] looks down at his board and the water below. Between his sneakers we can see two round openings – which look a lot like jet intakes. At the end of the video, [Frank] flies over the camera. stopping the action shows a split second where four exhaust holes are visible on the bottom of the board. These jets look quite a bit like model aircraft jet engines.

We don’t know exactly which engines [Frank] is using, but as an example, the Jet-Cat P 400 RX-G packs 88 lbs of thrust into a shell less than 6 inches in diameter, weighing less than 8 lbs. Four of those engines would provide 352 lbs of thrust. That’s plenty to lift [Frank], the board, and a few gallons of Jet-A strapped to his back.

Why no built-in intelligence? Even the smallest quadcopters have gyros, accellerometers, and PID loops keeping them upright. The problem boils down to the physics of jet engines. Active stability in a fixed pitch rotary blade system requires very fast throttle response. Quadcopters have this with their brushless motors. Turbines however, have throttle lag on the order of seconds. You can’t beat physics. Accelerating 3 or 4 pounds metal from 78,000 RPM (~70% throttle) to 98,000 RPM (~100 % throttle) takes time.

flyboard1Standing on a column of uncontrolled thrust would take quite a bit of skill on the part of the pilot. As it turns out, [Frank] is one of the world’s most experienced thrust riders. His previous invention, the Flyboard uses a personal watercraft to create a column of thrust which the rider stands on. These boards have become tremendously popular at vacation spots in the last few years. There are plenty of videos on [Frank’s] YouTube channel showing the amount of control a skilled ride has over the board. Loops, spins, and other aerobatics look easy.

With that much skill under his belt, [Frank] would have no problem keeping balanced on four jet engines.

Such a skilled rider means that control wouldn’t really be needed on the board. We’re betting that the only electronics are the remote throttle control and the Engine Control Computers (ECU) needed to keep the jets running and synchronized. The two electric ducted fans on the sides of the Flyboard Air appear to be running all the time, only shutting down when [Frank] lands the board.

One final thought – taking off and landing a jet vertically is difficult. Ground effects destabilize the craft. Engines can suck in their own exhaust, stalling them. These are problems faced by the harrier jump jet and the joint strike fighter. [Frank’s ] solution is not never get too close to the ground. If you watch closely, he takes off and lands from a perforated metal platform mounted off the back of a van. The metal doesn’t reflect enough thrust to cause the Flyboard to become unstable or stall.

So is the video real? We think so. This is an amazing achievement for [Frank Zapata]. Is it practical or safe? Heck no! Nor is it cheap – those engines cost €8,845.00 each.  That said, we’d love a chance to ride the Flyboard Air – after a few hours of training on the original Flyboard of course.

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After the Prize: What’s Next for the Light Electric Utility Vehicle

Winner of the third place in last year’s Hackaday Prize was [Chris Low]’s Light Electric Utility Vehicle. In case you think that once a Hackaday Prize is in the bag then that’s it and the project creator packs up and goes home, [Chris] dispels that idea, he’s invested his winnings straight back into his project and posted his latest progress on an improved Mk3 model.

Light Electric Utility Vehicle, 2015-style
Light Electric Utility Vehicle, 2015-style

We first covered the Light Electric Utility Vehicle back in June 2015 when it was first entered for the 2015 Hackaday Prize. The aim was to produce a rugged and simple small electric vehicle that could be powered by solar energy and that was suitable for the conditions found in South Sudan, where [Chris] works. The vehicle as we saw it then was an articulated design, with chain drive to bicycle-style wheels. The Mk3 version by comparison has lost the articulation in favour of rack-and-pinion steering, has in-hub motors instead of chain drive, and now features coil-spring suspension. You might comment that it has lost some of its original simplicity and become something more like a conventional electric UTV, but along the way it has also become more of a practical proposition as an everyday vehicle.

You can follow the entire build log on the Light Electric Utility Vehicle’s project page on hackaday.io, and below the break have a look at [Chris]’s video showing it in action. Continue reading “After the Prize: What’s Next for the Light Electric Utility Vehicle”

Autonomous Tractor Brings In The Harvest

[Matt Reimer] is a farmer in Southwestern Manitoba, Canada. It’s grain country, and at harvest time he has a problem. An essential task when harvesting is that of the grain cart driver, piloting a tractor and grain trailer that has to constantly do the round between unloading the combine harvester and depositing the grain in a truck. It’s a thankless, unrelenting, and repetitive task, and [Matt]’s problem is that labour is difficult to find when every other farmer in the region is also hiring.

His solution was to replace the driver with a set of Arduinos and a Pixhawk autopilot controlling the tractor’s cab actuators, and running ArduPilot, DroneKit, and his own Autonomous Grain Cart software. Since a modern tractor is effectively a fly-by-wire device this is not as annoying a task as it would have been with a tractor from several decades ago, or with a car. The resulting autonomous tractor picks up the grain from his combine, but he reminds us that for now it still deposits the harvest in the truck under human control. It is still a work-in-progress with only one harvest behind it, so this project is definitely one to watch over the next few months.

Writing from the point of view of someone who grew up on a farm and has done her share of harvest-time tractor driving it’s possible to see both the strengths and weaknesses of an autonomous grain cart. His fields on the Canadian prairie are very large and flat, there is plenty of space and the grain makes its way from the field to the elevator in a truck. To perform the same task in the smaller and irregular fields of southern England for example with a mile round trip down country lanes to the grain store would be a much greater challenge. Aside from that it’s worth noting that his John Deere is a 220hp 4WD workhorse that is capable of going over almost any terrain on a farm with very few obstacles able to stop it. This thing can do serious damage to life and property simply by running it over or driving straight through it, so safety has a dimension with an autonomous tractor in a way that it never will with for example a vacuum cleaner or even a lawnmower.

Those observations aside, this kind of technology undeniably represents a step change in farming practice on a par with the move from horse power to tractors in the first half of the last century. However the technological barriers that remain end up being solved, it’s likely that you’ll see plenty more machines like this in the fields of the future.

The video below the break shows the autonomous grain cart in action. Plenty of big-sky tractoring action, and for those of you unfamiliar with farming it should provide some understanding of the task of getting grain from combine to store.

We’ve talked about robotic farming more than once here at Hackaday. The gantry-based Farmbot, the six-legged Prospero robot farmer, or another hexapod confusingly also called Farmbot, for example. But these have all been hacker’s solutions to the problem using the concepts with which they are familiar. What makes [Matt]’s project different is that it is a farmer’s solution to a real farming problem by automating the machinery he already uses to do the job. Farmers have been doing what we would now call hacking at the hardware of their craft since time immemorial, [Matt]’s work is just the latest manifestation of a rich heritage.

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Automating RC Motor Efficiency Testing

Small brushless motors and LiPo batteries are one of the most impressive bits of technology popularized in recent years. Just a few years ago, RC aircraft were powered by either anemic brushed motors or gas. Quadcopters were rare. Now, with brushless motors, flying has never been easier, building electric longboards is simple, and electric bicycles are common.

Of course, if you’re going to make anything fly with a brushless motor, you’ll probably want to know the efficiency of your motor and prop setup. That’s the idea behind [Michal]’s Automated RC Motor Efficiency Tester, his entry to the 2016 Hackaday Prize.

[Michal]’s project is not a dynamometer, the device you should use if you’re measuring the torque or power of a motor. That’s not really what you want if you’re testing brushless motors and prop configurations, anyway; similarly sized props can have very different thrust profiles. Instead of building a dyno for a brushless motor, [Michal] is simply testing the thrust of a motor and prop combination.

The device is very similar to a device sold at Hobby King, and includes a motor mount, microcontroller and display, and a force sensor to graph the thrust generated by a motor and prop. Data can be saved to an SD card, and the device can be connected to a computer for automatic generation of pretty graphs.

Brushless motors are finding a lot of uses in everything from RC planes and quadcopters, to robotics and personal transportation devices. You usually don’t get much of a data sheet with these motors, so any device that can test these motors will be very useful.

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Bike Power Meter with Crank-mounted WiFi Strain Gauges

In any motorsport, the more you know about how the engine is performing, the better a driver is likely to do in a race. That holds for bicycles, too, where the driver just happens to also be the engine. There are plenty of cheap bike computers on the market, but the high-end meters that measure power output are a bit pricey. [chiprobot] is looking to change that with a home-brew, low-cost bike power meter.

The project still appears to be in the proof-of-concept phase, but it’s an interesting concept for sure. The stock crank arms are carefully fitted with two pairs of tiny strain gauges. The gauges are wired in a Wheatstone bridge arrangement, with one gauge in each pair mounted perpendicular to the force on the crank to serve as a static reference. Output from the bridge is fed to an HX711 instrumentation amplifier. The demo video below shows how sensitive the bridge and 24-bit amp are.

The goal is to send crank data to a handlebar-mounted UI via WiFi with a pair of ESP8266 modules. We like the idea of a bicycle area network, but [chiprobot] has his work cut out for him in terms of ruggedizing and weatherproofing all this gear. We’ll be sure to keep an eye on this project. In the meantime, there’s plenty to learn from this bike power meter project we covered last year.

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TrainLight: Transit Info At A Glance

In a world of sensory overload, sometimes it’s nice to get the information you need without a bunch of clutter. [Savage] has created an attractive and minimalist system to display the current wait times for specific trains in his San Francisco neighborhood.

trainlight-legendIt’s basically a Spark Core and a 60 LED-per-meter strip of WS2812Bs. A 1000µF cap filters the power coming in from a switching adapter and a resistor limits the level-shifted logic going to the LEDs. Eight barriers made from card stock keep the light zones from bleeding together. The sides of the square canvas panel indicate cardinal directions and are oriented to [Savage]’s southern-facing house.

The server gets prediction data every 30 seconds using the RESTbus JSON API. [Savage] added in a bit of time for walking down the stairs, putting shoes on, and walking to each stop. TrainLight receives these times over WiFi and lights the LEDs accordingly. If a section isn’t lit at all, the wait time for that line is greater than 10 minutes. Dark green means you have 5-10 minutes to get there, and pale green means 2-5 minutes. If the LEDs are yellow, you’d better put on your running shoes.

This is a fairly simple build with a focus on subtlety. Even before guests in his house understand what they’re looking at, [Savage]’s TrainLight makes for an interesting conversational piece of blinkenlights and doubles as illumination for the stairs. There’s a slightly sped-up demo after the break.

Want to make your own? [Savage] has a tutorial page and his code is up on the gits. Blinky lights are also good for telling you whether the trains are running at all.

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