Once you have a track and a kart to race on it, what’s missing? A lap counter that can give your lap times in hardcopy, obviously! That’s what led [the_anykey] to create the Arduino-based Lap Timer to help him and his kids trim those precious seconds off their runs, complete with thermal printer for the results.
The hardware uses an infrared break-beam sensor module (a Velleman PEM10D) to detect when a kart passes by. This module is similar to a scaled-up IR reflective object sensor; it combines an IR emitter and receiver on one end, and is pointed at a reflector placed across the track, up to 10 meters away. When a kart breaks the beam, the module reports the event to the rest of the hardware. Only needing electronics on one side allows the unit to be self-contained.
An obvious shortcoming of this system is the inability to differentiate between multiple karts, but for timing a single driver’s performance it does the trick. What’s great about this project is it showcases how accessible hardware is today; a device like this is possible to put together with what are essentially off-the-shelf components available to any hobbyist, using an Arduino as the glue to hold it together. We’d only comment that a red-tinted piece of plastic as an overlay for the red display (and a grey-tinted one for the green) would make the LED displays much easier to read. Still, this is a very clean and well-documented build. See it in action in the video embedded below.
“DroneClash” is a competition to be held on December 4th (save the date!) in a hangar at Valkenburg airfield in the Netherlands. The game? Teams try to destroy each others’ quadcopters, navigate through a “Hallway of Doom, Death, and Destruction”, and finally enter a final phase of the game where they try to defend their “queen” drone while taking out those of their opponents.
This sounds like crazy and reckless fun. Surprisingly, it’s being sponsored by the Technical University of Delft’s Micro Air Vehicle (MAV) lab. The goal is to enable a future of responsible drone use by having the ability “to take them out if necessary”.
Drone development has grown hugely in recent years, and you can see the anti-drone industry growing too. Ideally, these developments keep each other in check and result in a safe and responsible incorporation of drones in our daily lives. We are organising DroneClash to generate new ideas in order to encourage this process.
We do have to ask ourselves why anyone would want to use another quadcopter to take out illegally operated quadcopters — there must be a million more effective means from a policing standpoint. On the other hand, if we were re-shooting “Hackers” right now, and looking for a futuristic sport, we would swap out rollerblading for drone combat. Registration opens this week. Gentlebots, start your engines.
The typical boards you order from OSH Park and the like usually come with 1-ounce copper – that’s one ounce of copper cladding per square foot of board. For those averse to Imperial units, that’s a copper layer 34 micrometers thick. [limpkin]’s Formula E control board needs to carry a lot of current, so he specified 700-micrometer thick cladding, or 20-oz per square foot. The board pictured cost $2250, so you’d figure soldering on the components would be an exotic process, but aside from preheating the board, [limpkin] took it in stride. Check out the image gallery of the session and you’ll see nothing but a couple of regular high-wattage soldering irons, with dirty tips to boot.
It’s pretty neat comparing what’s needed for power electronics versus the normal small signal stuff we usually see. We’d recommend looking at [Brian Benchoff]’s “Creating a PCB in Everything” series for design tips, but we’re not sure traditional tools will work for boards like these. And just for fun, check out the Formula E highlights video below the break to see what this build is part of.
It wasn’t the first time his group had worked together on something a little different, such as a robot that can deploy an antenna by climbing poles. However, this one had a time limit and they ended up trying to fit it all in the week before the race.
They had a pretty good design. [ITMAN496] had modeled the entire frame in SketchUp and even did physics simulations to get the steering just right. However, the best laid plans of mice and men often don’t fully take into account just how hard it is to get the motor drivers they bought working.
In the end, what they really needed was time to test. The setscrews couldn’t hold the motor on the shaft, the electronics needed debugging, and one of the belts was too long. The design was solid, but without time to percussively maintain the last bugs out of the system, it just wasn’t going to run.
[ITMAN496] is taking this lesson properly; he’s already planning for next year’s run, but this time he’ll have time to test. We must commend him — the build under these time constraints was still impressive. Even more so that he took the time to document everything while it was happening, and to share the story of shortfall after the fact. We’re always on the hunt for documented fails (the best way to really learn something).
In the drag racing world, a Christmas tree is the post at the start line that sequentially lights up a set of yellow lights followed shortly after by a green light to tell the drivers to go, the lights obviously giving it its seasonal name. Included at the base of the tree are lasers to detect the presence of the cars.
[Mike] not only made his own Christmas tree for his RC cars, but he even made an end-of-track circuit with LED displays telling the cars how long they took. Both start and finish hardware are controlled by Pololu Wixel boards which has TI CC2511F32 microcontrollers with built-in 2.4 GHz radios for wireless communications.
In addition to the LEDs, the Christmas tree has a laser beam using a 650nm red laser diode for each car at the start line that’s aimed at a TEPT5600 phototransistor. If a car crosses its beam before the green light then a red light signals the car’s disqualification.
The end-of-track circuit has 7-segment displays for each car’s time. [Mike] designed the system so that the Christmas tree’s microcontroller tells the end-of-track circuit’s microcontroller when to reset the times, start the times, and clear the times should there be a disqualification. The finish line controller has lasers and phototransistors just like the starting line to stop the timers.
Oh, and did we mention that he also included 1980’s car racing game sounds? To see and hear it all in action check out the video after the break. If the cars seem a little drunk it’s because pushing left or right on the controller turns the wheel’s fully left or right.
One problem with engineering education today is a lack of experimental teaching. Oh sure you may have a project or two, but it’s not the focus of the program because it’s hard to standardize a test around. Typically sections of the field are taught in a highly focused theoretical course by a professor or graduate student with a specialization in that section. Because classes treat individual subject areas, it’s entirely possible to get a really good understanding of two pieces of the same puzzle, but never realize that they fit together to make a picture. It’s only when a freshly minted engineer gets out into the real world that they start to make the connections between seemingly disparate fields of knowledge.
This is why Carroll Smith’s book “Engineer to Win” is so good. He spent a lifetime as a practicing engineer in a field where a small failure could mean the death of a friend. So when he set out to write a book, he wrote a book that related everything needed to properly conceptualize and solve the mechanical engineering problems in his field.
One warning though; the book is not for the faint of heart. If you want to learn something difficult well, then this is book for you. Carroll skips the comforting analogies and gives the information exactly. It can get a little dense, but he makes the assumption that the reader is there to learn and, most importantly, understand. This takes work.
For example, you can’t really understand why a rolled bolt is stronger than a bolt cut on a screw machine until you understand how metal works on a crystalline level. The same goes for metal fatigue, brittle fractures, ductile failures, and all the maladies that metal can suffer. The difference between an engineer and a technician is this deep understanding. Otherwise the equations learned are just parts in a toolbox and not paint on an artist’s palette.
This is why the first half of the book is dominated by all things metallurgical. The book starts with the simple abstractions of the crystalline structures of metal. Unlike my materials class in university, it maintains a practical bend to the presentation of the information throughout the whole process. For example, it moves on to what all this practically means for metals undergoing stresses and failures before it launches into a (short) digression on how metals are made and their history.
This first half of the book touches on non-ferrous metals and their proper use as well. After that comes some of the best explanations of metal fatigue, fasteners, and metal bonding I’ve ever read. When the failure of a joint causes a mechanism to fail in a toaster that’s one thing, but when it fails in a racecar people get hurt. Carroll is very exacting in what constitutes a forgivable oversight in engineering, and what does not.
Once the book has finished conveying a working understanding of metals and fasteners it seems to fracture into a pot-luck of different racecar-related topics. During my first reading of the book I resisted this strange turn of events. For example, I didn’t really want to read about racecar plumbing in the eighties, or what kind of springs and aerofoils Carroll likes. However, when I reread those sections in a more focused manner, I realized that many of them were teaching the practical application of the knowledge learned in the previous chapters. How does the metal make a good spring? Why is one kind of plumbing better than another?
Importantly, the anecdotes at the end of the book impart an understanding of the importance of professionalism in engineering. What is the true responsibility of an engineer? He teaches not to take the trust others place in your skills for granted. He teaches to trust in the skills of others. The book teaches humility as an engineer. He shows the kind of person one can become after a lifetime of earnest study in their craft.
Thanks to reader, [Dielectric], for recommending the book to me. Also, from the bit of research I’ve done, the older motorworks edition is generally considered to have better quality reproductions of the diagrams than the newer printings of the book.
We weren’t certain if this Star Wars fan film was out kind of thing until we saw the making of video afterwards. They wanted to film a traditional scene in a new way. The idea was to take some really good quadcopter pilots, give them some custom quadcopters, have them re-enact a battle in a scenic location, and then use some movie magic to bring it all together.
The quadcopters themselves are some of those high performance racing quadcopters with 4K video cameras attached. The kind of thing that has the power to weight ratio of a rocket ship. Despite what the video implies, they are unfortunately not TIE Fighter shaped. After a day of flying and a few long hikes to retrieve the expensive devices after inevitable crashes (which, fortunately, provided some nice footage), the next step was compositing.
However, how to trick the viewer into believing they were in a X-Wing quadcopter? A cheap way to do it would be to spend endless hours motion tracking and rendering a cockpit in place. It won’t look quite real. The solution they came up with is kind of dumb and kind-of brilliant. Mount a 3D printed cockpit on a 2×4 with a GoPro. Play the flight footage on a smartphone while holding the contraption. Try to move the cockpit in the same direction as the flight. We’re not certain if it was a requirement to also make whooshing and pew pew laser noises while doing so, but it couldn’t hurt.
In the end it all came together to make a goofy, yet convincingly good fan film. Nice work! Videos after the break.