The Parallax Propeller is an exceptionally interesting chip that doesn’t get the love it deserves. It’s a 32-bit microcontroller with eight independent cores that are each powerful enough to do some real computation. Around this time last year, the source for the Propeller was opened up and released under GPL 3.0, along with the mask ROM and an interpreter for the Propeller-specific language, Spin. This release is not only a great educational opportunity, but a marvelous occasion to build some really cool hardware as [antti.lukats] is doing with the Soft Propeller.
[antti]’s Soft Propeller is based on the Xilinx ZYNQ-7000, a System on Chip that combines a dual core ARM Cortex A9 with an FPGA with enough logic gates to become a Propeller. The board also has 16MB of Flash used for configuration and everything fits on a Propeller-compatible DIP 40 pinout. If you’ve ever wanted to play around with FPGAs and high-power ARM devices, this is the project for you.
[antti] already has the Propeller Verilog running on his board, and with just a bit more than 50% of the LUTs used, it might even be possible to fit the upcoming Propeller 2 on this chip. This build is just one small part of a much larger and more ambitious project: [antti] is working on a similar device with HDMI, USB, a MicroSD, and 32MB of DDR2 RAM. This will also be stuffed into a DIP40 format, making it an incredibly powerful system that’s just a bit larger than a stick of gum.
[Andrey Nechypurenko] has posted the second part of his robotics ground vehicle design guide. In his first post [Andrey] detailed the mechanical design decisions he faced. [Andrey] now begins covering the electrical components, starting with manual control using a standard radio control system. To accomplish this an RC system was used with an MD22 h-bridge driver and a picoUPS.
The MD22 is a neat motor control board which can take the PWM signals from the radio controller and use this to drive the DC motors. Optionally it can also use an I2C interface, giving a nice migration path to integrate with a microcontroller. Until that happens this can’t really be called a robot — its more of an RC vehicle. But the iterative design and build process he’s using is a good one!
The picoUPS provides on-board battery charging. Due to its UPS heritage it also allows the vehicle to be powered from an external supply, which has proved useful during development. Finally, a 5v regulator was required to supply the on-board digital logic. [Andrey] wanted a quick drop in solution with a budget large enough to allow for future expansion and went with the Pololu D15V35F5S3 which can supply 3.5 amps in a small and easy to use module.
After breadboarding the system [Andrey] fabricated a PCB to integrate all the components. The next step is to add sensors and and embedded computer to the platform.
Continue reading “Robot Control Ties RC Receiver To Motor Controller” →
For almost exactly 200 years, the Guinness brewery in Dublin, Ireland employed extremely skilled craftsmen to shape and construct wooden casks by hand. These men were called coopers, and plying their trade required several years of apprenticeship. The cooperage was a kind of closed society as many of the positions were passed down through generations of families. With the rise of aluminium and then stainless steel barrels in the late 1950s, the master coopers of Guinness became a dying breed.
Almost every step of the coopering process shown in this film is done without any kind of precise measurement. A master cooper like [Dick Flanagan] here needs only his eyes and his practiced judgment. His barrels start out as oak planks called ‘staves’ that have been drying in racks for at least two years. A cooper selects the staves that strike his fancy and he saws off the ends. This seems to be the only part of the process where a power tool is used.
The cooper shapes each stave by hand with axe and adze so that its ends are tapered just so. Once he has shaped enough of them to make a barrel, he arranges them in a cylinder around the inside of a metal band known as a hoop. The bound staves are steamed for half an hour to make them pliable enough for shaping.
After steaming, the splayed end of the staves are bound with wire rope to pull them close enough together that a hoop can be fitted over them. The inside of the cask is then charred with burning oak shavings, a process that seals the wood and removes its acidity. After this, the ends are sanded and the bunghole is drilled.
For each barrel, the cooper crafts a custom set of hoops. These are installed after the outside of the barrel has been shaved smooth. Finally, the heads that cap each end of the cask are made from more oak staves held together with dowel rods. This is the only time the cooper uses a tool to measure anything, and he does so to achieve the proper circumference on the heads. He bevels the edges so the heads will fit into bored-out grooves in the cask walls. Once they’re seated, the keg is ready for dark, rich stout.
Continue reading “Retrotechtacular: Coopering Guinness Barrels By Hand” →
We’re not giving away a prize. We’re making it your priority to share hard-earned knowledge. On August 17th we’ll start testing the Best Products. Ten will be recognized as finalists, one will be awarded $100,000 but everyone will benefit.
We want to highlight a set of amazing products. These are well-built designs that deserve recognition for doing the extra 90% of work involved in designing for production. This has not traditionally been the fun or sexy part of product development, but that will change.
What does it mean to be a product? Engineering something to be manufactured and sold is a different ball game compared to going from a concept to a working prototype. This is often the downfall of the crowd funding campaign. You were prepared to hammer out 100 units with your friends in someone’s basement. Oops, you now have 1400 backers and have overshot the point at which your plans could work. If properly engineered, a product can be scaled without completely redesigning it.
This is where we are right now. The barriers for having a professionally fabbed PCB made are completely non-existant. But the barriers for making that small-run PCB proof-of-concept into a product are still formidable. We’re changing that and you’re the key to it all. It starts by sharing great examples of how these problems are being overcome. Start-ups should be leading the way, pollinating this information by talking about your experience, your ideas, and your vision.
Write about your successes, failures, and solutions. Show us what happened during the evolution of your product and secure the title of Best Product.
[Photo Credit: Hilmers Studios Technical Illustrations]
Submit your entry for Best Product before 8/17/15. Don’t forget to opt-in for best product by using the “Submit-to Best Product” option on the left sidebar of your project page. Qualifying entries which have sent in three working beta-test units by the entry deadline will be considered for the Best Product prizes. See the entries so far and drop into our live chat at 6:00 PDT Today.
[Carlos] needed an ADC with a 50 nanosecond sample period for his laser lab, that’s 20Msps! (20 million samples a second). While in recent years, commodity ADCs reaching into the low GSPS have become available, integrated acquisition systems are still somewhat expensive. So [Carlos] decided to do what every good hacker does, and built his own solution. His project post pretty much just links to a whitepaper he wrote (PDF) so we’ll try and boil it down for you:
In order to simplify development [Carlos] borrowed a technique commonly used in the first era of digital oscilloscopes, Equivalent Sampling Time.
The figure to the right is from the TDS460 manual. While it may seem counter intuitive to those only familiar with modern scopes, the TDS460 achieved a 400MHz bandwidth using a 100MSPS ADC. In order to achieve this the scope acquires a single trace in multiple cycles, each time offsetting the acquisitions as shown and combining the result.
In this way, early digital scope developers could sidestep the limitations of the available ADCs to achieve a higher effective bandwidth. However there is of course one catch: the technique only works for periodic signals.
This was fine for [Carlos] who implemented a technique on a Cypress PSoC 4, which provides analog FPGA-like functionality. By offsetting the ADC trigger he has able to achieve an EST of 48MHz using a ADC sampling at 1MHz. If you want a little help getting into PSOC 4 yourself, check out the guide that [Bil Herd] made.
Neat hack [Carlos] and we hope to hear more about your laser lab in the future.
There is no denying that personal drones are in the public eye these days. Unfortunately they tend to receive more negative press than positive. This past weekend, there were news reports of a wildfire in California. Efforts to fight the fire were hampered when no less than five drones were spotted flying in the area. Some reports even stated that two of the drones followed the firefighting aircraft as they returned to local airports. This is the fourth time this month firefighting planes have been grounded due to unmanned aircraft in the area. It’s not a new problem either, I’ve subscribed to a google alert on the word “Drone” for over a year now, and it is rare for a week to go by without a hobby drone flying somewhere they shouldn’t.
The waters are muddied by the fact that mass media loves a good drone story. Any pilotless vehicle is now a drone, much to the chagrin of radio control enthusiasts who were flying before the Wright brothers. In this case there were two fields relatively close to the action – Victor Valley R/C Park, about 10 miles away, and the Cajun Pass slope flying field, which overlooks the section of I-15 that burned. There are claims on the various R/C forums and subreddits that it may have been members from either of those groups who were mistaken as drones in the flight path. Realistically though, Victor Valley is too far away. Furthermore, anyone at the Cajun pass flying site would have been fearing for their own safety. Access requires a drive through 3 miles of dirt road just to reach the site. Not a place you’d want to be trapped by a wildfire for sure. Who or whatever was flying that day is apparently lying low for the moment – but the problem persists.
Rules and Regulations
In the USA, the FAA rules are (finally) relatively clear for recreational drone operations. The layman version can be found on the knowbeforeyoufly.org website, which was put together by the Academy of Model Aeronautics (AMA), The Association for Unmanned Vehicle Systems International (AUVSI), and other groups in partnership with the FAA.
Continue reading ““Drones” Endanger Airborne Wildfire Fighting” →
Any NYC hackers may have noticed something a bit odd this summer while taking a walk… Giant tanks of the Liquid Nitrogen have been popping up around the city.
There are hoses that go from the tanks to manholes. They’re releasing the liquid nitrogen somewhere… Are they freezing sewer alligators? Fighting the Teenage Mutant Ninja Turtles? Or perhaps, cooling our phone lines??
Luckily, we now have an answer. Popular Science writer [Rebecca Harrington] got to investigate it as part of her job. As it turns out, the liquid nitrogen is being used to pressurize the cables carrying our precious phone and internet service in NYC. The cables have a protective sheath covering them, but during construction and repairs, the steam build up in some of the sewers can be too much for them — so they use liquid nitrogen expanding into gas to supplement the pressurized cables in order to keep the them dry. As the liquid nitrogen boils away, it expands 175 times which helps keep moisture out of the cables.
Continue reading “Why Is There Liquid Nitrogen On The Street Corner?” →