Testing rocket motors is a dangerous business, as they have an annoying habit of releasing all of that energy a little quicker than you might like. [Jeff Hopkins] knows this, so he made his own wireless rocket motor analyzer that allows him to trigger, test and monitor rocket motors from a safe distance. This involves more than just pushing a button and watching them go whoosh: his platform measures the thrust of the prototype over 90 times a second and transmits this data to him remotely for logging and later analysis. His current prototype can measure engines with up to 400 lbs of thrust. That is a lot, so it is a good thing that his rig can also remotely arm, fire or safe the motors, all over a 70cm wireless radio link that keeps him safely out of the way. It is also built of cheap parts, so if a RUD (Rapid Unplanned Disassembly) does occur, it won’t cost him much to rebuild and start again.
This project is part of a bigger plan: [Jeff] is looking to build a high-power launch platform that can launch an electronics platform high above the earth. Could this be the beginning of the race to be the first hacker in space? We shall see…
For electric and remote control vehicles – from quadcopters to electric longboards – the brains of the outfit is the Electronic Speed Controller (ESC). The ESC is just a device that drives a brushless motor in response to a servo signal, but in that simplicity is a lot of technology. For the last few months, [Ben] has been working on a completely open source ESC, and now he’s riding around on an electric longboard that’s powered by drivers created with his own hands.
The ESC [Ben] made is built around the STM32F4, a powerful ARM microcontroller that’s able to do a lot of computation in a small package. The firmware is based on ChibiOS, and there’s a USB port for connection to a sensible desktop-bound UI for adjusting parameters.
While most hobby ESCs are essentially black boxes shipped from China, there is a significant number of high performance RC pilots that modify the firmware on these devices. While these new firmwares do increase the performance and response of off-the-shelf ESCs, building a new ESC from scratch opens up a lot of doors. [Ben]’s ESC can be controlled through I2C, a UART, or even a CAN bus, greatly opening up the potential for interesting electronic flying machines. Even for ground-based vehicles, this ESC supports regenerative braking, sensor-driven operation, and on-board odometry.
While this isn’t an ESC for tiny racing quadcopters (it’s complete overkill for that task) this is a very nice ESC for bigger ground-based electric vehicles and larger aerial camera platforms. It’s something that could even be used to drive a small CNC mill, and certainly one of the most interesting pieces of open source hardware we’ve seen in a long time.
Continue reading “Open Source ESC Developed for Longboard Commute”
Concrete – it’s all around you. You probably walk on it, drive on it, and maybe even sit on it! From a civil engineering standpoint, concrete really is a miracle material. But, it does have its downsides, especially in heavily developed urban areas. One of the most glaring of those downsides is the tendency for water to pool and flood on concrete. However, a new concrete formula could dramatically improve that by allowing water to drain quickly through the concrete itself.
While all unsealed concrete technically absorbs water, it does so very inefficiently and quickly becomes saturated. Once that happens, water will pool on the surface. This causes obvious problems for cars, as they become susceptible to hydroplaning. It also creates the potential for flooding in heavily paved areas.
This new concrete formula, called Topmix Permeable, is designed to reduce pooling by letting the water flow through at the rate of 600 liters per minute per square meter! It does this by using larger gravel pieces in the mix, which leaves bigger gaps for the water to drain down into. From there, it can be absorbed by the underlying soil, or routed safely away from roadways and parking lots.
Of course, this formula isn’t perfect. Its ability to pass through water also makes it likely to crack and quickly deteriorate in cold climates, as the water freezing and thawing inside the concrete will easily damage it. But, in warmer climates that receive a lot of rainfall in bursts, it could significantly improve safety.
Continue reading “Concrete With a Drinking Problem Could Reduce Flooding”
Want to learn why ducted propellers improve both thrust and efficiency? Well, we’ve got both the lesson and the teacher for you. [Bruce Simpson] isn’t exactly a household name, but we bet most of you already know who he is. He’s the guy from New Zealand that in 2003 set out to make a $5000 DIY Cruise Missile – and he claims that he would have succeeded if the NZ Government hadn’t got in the way. Now-a-days [Bruce] focuses most of his energy on his two YouTube channels, RC Model Reviews and XJet.
Back to the lesson at hand: In the video after the break, he does a wonderful job explaining how the walls of a duct work to stop the high pressure area of the propeller from moving to the low pressure area. You’ll see something similar on the wings of jets aircraft. There will be a small vertical fin on the end of the wing, and much like a duct, it’s job is to physically separate the two areas and prevent tip vortex effects. That in turn increases efficiency. [Bruce] has some other great RC/model type videos, so if you like what you see, you might want to subscribe. Or you can learn more about the DIY Cruise Missile saga.
Continue reading “A Guy Named Bernoulli and Ducted Propeller Designs”
I came across an interesting question this weekend: how do you establish your East/West location on the globe without modern technology? The answer depends on what you mean by “modern”, it turns out you only have to go back about three centuries to find there was no reliable way. The technology that changed that was a clock; a very special one that kept accurate time despite changing atmospheric conditions and motion. The invention of the Harrison H1 revolutionized maritime travel.
We can thank Andy Weir for getting me onto this topic. I just finished his amazing novel The Martian and I can confirm that George Graves’ opinion of the high quality of that novel is spot on. For the most part, Andy lines up challenges that Mark Watney faces and then engineers a solution around them. But when it came to plotting location on the surface of Mars he made just a passing reference to the need to have accurate clocks to determine longitude. I had always assumed that a sextant was all you needed. But unless you have a known landmark to sight from this will only establish your latitude (North/South position).
Continue reading “Navigating the Oceans is Deadly Without a Clock”
Every so often – and usually not under the best of circumstance – the field of engineering as a whole is presented with a teaching moment. Volkswagen is currently embroiled in a huge scandal involving emissions testing of 11 Million diesel cars sold in recent years. It’s a problem that could cost VW dearly, to the tune of eighteen Billion dollars in the US alone, and will, without a doubt, end the careers of more than a few Volkswagen employees. In terms of automotive scandals, this is bigger than Unsafe at Any Speed. This is a bigger scandal than the Ford Pinto’s proclivity to explode. This is engineering history in the making, and an enormously teachable moment for ethics in engineering.
Continue reading “Ethics in Engineering: Volkswagen’s Diesel Fiasco”
Talk about an awesome project. [Lucas Evanochko] was commissioned to build this totally rad Delorean style golf Cart for Red Deer College’s 30th annual Golf Tournament.
According to him, it’s been about 600 hours in the making – and they only started building it in July. This past week was its big unveiling, and it has had an overwhelmingly positive response so far!
They started with one of the club’s golf carts and modified it heavily, relying on the automotive expertise of [David Keykants] and [John Perrin] to turn it into the aw-worthy time machine it is today. It has a 7” tablet built right into the dash to play music and use the Fluxy88 Time Circuits app. A big array of arcade buttons hooked up to an Adafruit Audio FX board play various sound bites from the movie, including the theme music!
All the accessories are powered off of a separate 12V system from the main 48V drive line. Oh and the Flux Capacitor? It’s controlled by a Trinket Pro. Check it out after the break. We love the detail that went into this!
Continue reading “Quick Marty! We Have To Go Back, With the Golf Cart!”