TeensyStep – Fast Stepper Library For Teensy

October 17, 2017 by 27 Comments

The Teensy platform is very popular with hackers — and rightly so. Teensys are available in 8-bit and 32-bit versions, the hardware has a bread-board friendly footprint, there are a ton of Teensy libraries available, and they can also run standard Arduino libraries. Want to blink a lot of LED’s? At very fast update rates? How about MIDI? Or USB-HID devices? The Teensy can handle just about anything you throw at it. Driving motors is easy using the standard Arduino libraries such as Stepper, AccelStepper or Arduino Stepper Library.

But if you want to move multiple motors at high micro-stepping speeds, either independently or synchronously and without step loss, these standard libraries become bottlenecks. [Lutz Niggl]’s new TeensyStep fast stepper control library offers a great improvement in performance when driving steppers at high speed. It works with all of the Teensy 3.x boards, and is able to handle accelerated synchronous and independent moves of multiple motors at the high pulse rates required for micro-stepping drivers.

The library can be used to turn motors at up to 300,000 steps/sec which works out to an incredible 5625 rpm at 1/16 th micro-stepping. In the demo video below, you can see him push two motors at 160,000 steps/sec — that’s 3000 rpm — without the two arms colliding. Motors can be moved either independently or synchronously. Synchronous movement uses Bresenham’s line algorithm to plan motor movements based on start and end positions. While doing a synchronous move, it can also run other motors independently. The TeensyStep library uses two class objects. The Stepper class does not require any system resources other than 56 bytes of memory. The StepControl class requires one IntervallTimer and two channels of a FTM  (FlexTimer Module) timer. Since all supported Teensys implement four PIT timers and a FTM0 module with eight timer channels, the usage is limited to four StepControl objects existing at the same time. Check out [Lutz]’s project page for some performance figures.

As a comparison, check out Better Stepping with 8-bit Micros — this approach uses DMA channels as high-speed counters, with each count sending a pulse to the motor.

Thanks to [Paul Stoffregen] for tipping us off about this new library. Continue reading “TeensyStep – Fast Stepper Library For Teensy” →

Snazzy Balun Lets Ham Use Off-The-Shelf Coax

October 16, 2017 by 42 Comments

It’s a dilemma many hams face: it’s easy to find yourself with a big spool of RG-11 coax cable, usually after a big cable TV wiring project. It can be tempting to use it in antenna projects, but the characteristic impedance of RG-11 is 75 Ω, whereas the ham world is geared to 50 Ω. Not willing to waste a bounty of free coax, one ham built a custom 1:1 current balun for a 75 Ω dipole.

Converting between balanced and unbalanced signals is the job of a balun, and it’s where the device derives its name. For hams, baluns are particularly useful to connect a dipole antenna, which is naturally balanced, to an unbalanced coax feedline. The balun [NV2K] built is a bifilar 1:1 design, with two parallel wires wound onto a ferrite core. To tweak the characteristic impedance to the 75 Ω needed for his antenna and feedline, [NV2K] added short lengths of Teflon insulation to one of the conductors, which is as fussy a bit of work as we’ve seen in a while. We appreciate the careful winding of the choke and the care taken to make this both mechanically and electrically sound, and not letting that RG-11 go to waste is a plus.

With as much effort as hams put into antenna design, there’s a surprising dearth of Hackaday articles on the subject. We’ve talked a bit about the Yagi-Uda antenna, and we’ve showcased a cool magnetic loop antenna, but there’s precious little about the humble dipole.

[via r/amateurradio]

Dubai Police Test Quadcopter Motorcycle

October 16, 2017 by 69 Comments

If you ever wish you could be on your quadcopter when you fly it, you will really want to see the video showing the Dubai police department testing the Hoverbike. The Russian company Hoversurf that markets the device doesn’t provide a lot of technical details, but it looks fairly simple. It is basically a motorcycle seat along with a big quadcopter. From the videos about the device, you can deduce that the pilot can control it or you can fly it remotely. You can see one of the videos, below.

There are a few things that worry us here. Of course, the huge spinning propellers as the pilot’s knee level should give you sweaty palms. In the demo, they even show the removal of the propeller guards before the test flight but let’s be honest, those don’t look like they would keep a falling pilot out of the rotors at all anyway. When looking beyond the hype we find it curious that the demo doesn’t show many (if any) shots of the pilot making a turn. The benefit of a vehicle like this to police should be maneuverability and from what we saw the Hoversurf is still limited.

So is it real? Hard to say. The short videos mostly show vertical or horizontal flight with no maneuvering. Is it hard to turn? Is the battery life really short? One other oddity: When we first saw a letter from the US Patent Office on their site, we thought they might have some new technology. However, that letter is simply showing they registered a trademark and doesn’t reference a patent. If there is a patent we want to know what is new and novel here.

Of course, we know it’s possible to build such a machine since we saw [Colin Furze] do it with two rotors instead of four. The US Department of Defense is working on something with a company called Malloy and there are other practical examples. There are also some less practical examples. What we’re really on the lookout for is a product that works so well it will actually be used. You know, like those Segways that airport police use, right?

We hope Hoversurf can bring this to market because we definitely want one. There’s no reason to think they can’t, but we do wish there were more details forthcoming.

Echo Dot Finds Swanky New Home In Art Deco Speaker

October 16, 2017 by 15 Comments

The phrase “They don’t make them like they used to” is perhaps best exemplified by two types of products: cars and consumer electronics. Sure, the vehicles and gadgets we have now are so advanced that they may as well be classified as science-fiction when compared to their predecessors, but what about that style. Our modern hardware can rarely hold a candle to the kind of gear you used to be able to buy out of the “Sears, Roebuck and Company” catalog.

So when [Democracity] came into possession of a wickedly retro art deco speaker, it’s no surprise he saw it as a perfect opportunity to bring some of that old school style into the 21st century by rebuilding it with an Amazon Echo Dot at its core. The fact that the original device was a speaker and not a full radio made the conversion much easier, and will have everyone trolling yard sales for months trying to find a donor speaker to build their own.

To start the process, [Democracity] popped the panels off and ripped out what was left of the speaker’s paper cone and coil. In a stroke of luck, the opening where the driver used to go was nearly the perfect size to nestle in the Echo Dot. With a 3D printed cradle he found on Thingiverse and a liberal application of epoxy, the Dot could get snapped into the speaker like it was always meant to be there.

[Democracity] then picked up some absolutely gorgeous speaker cloth on eBay and hot glued it to the inside of the panels. What was presumably the volume knob was pulled out of the bottom and turned out to be a perfect place to run the Dot’s USB cable out of.

A lesser man would have called this project completed, but [Democracity] knows that no hack is truly complete without the addition of multicolored blinking LEDs. With the RGB LED strips installed inside, the light is diffused through the cloth panels and creates a pleasing subtle effect. You can almost imagine a couple of vacuum tubes glowing away inside there. Judging by the final product, it’s no surprise [Democracity] has a fair bit of experience dragging audio equipment kicking and screaming into the modern era.

This isn’t the first time we’ve seen an old piece of audio equipment get a high-tech transfusion, and isn’t even the first time we’ve seen the Dot used to do it. But it’s certainly the one we’d most like to see sitting on our shelf.

Aussies Propose Crackdown On Insecure IoT Devices

October 16, 2017 by 36 Comments

We’ve all seen the stories about IoT devices with laughably poor security. Both within our community as fresh vulnerabilities are exposed and ridiculed, and more recently in the wider world as stories of easily compromised baby monitors have surfaced in mass media outlets. It’s a problem with its roots in IoT device manufacturers treating their products as appliances rather than software, and in a drive to produce them at the lowest possible price.

The Australian government have announced that IoT security is now firmly in their sights, announcing a possible certification scheme with a logo that manufacturers would be able to use if their products meet a set of requirements. Such basic security features as changeable, non-guessable, and non-default passwords are being mentioned, though we’re guessing that would also include a requirement not to expose ports to the wider Internet. Most importantly it is said to include a requirement for software updates to fix known vulnerabilities. It is reported that they are also in talks with other countries to harmonize some of these standards internationally.

It is difficult to see how any government could enforce such a scheme by technical means such as disallowing Internet connection to non-compliant devices, and if that was what was being proposed it would certainly cause us some significant worry. Therefore it’s likely that this will be a consumer certification scheme similar to for example the safety standards for toys, administered as devices are imported and through enforcement of trading standards legislation. The tone in which it’s being sold to the public is one of “Think of the children” in terms of compromised baby monitors, but as long-time followers of Hackaday will know, that’s only a small part of the wider problem.

Thanks [Bill Smith] for the tip.

Baby monitor picture: Binatoneglobal [CC BY-SA 3.0].

Hackaday Prize Entry: Giving Phones Their Tactile Buttons Back

October 16, 2017 by 10 Comments

In the before-times, we could send text messages without looking at our phones. It was glorious, and something 90s Kids™ wish we could bring to our gigantic glowing rectangles stuck in our pocket. For his Hackaday Prize Entry, [Kyle] is bringing just a little bit of this sightless functionality back to the modern smartphone. He’s building a tactile remote control for smartphones. With this device, you can navigate through icons, push buttons, and even zoom in on maps with real, physical controls.

This keyboard is built around a handful of Cherry MX mechanical key switches for a great tactile feel, and a single capacitive touch strip for zooming in and out on the screen. This is pretty much exactly what you want for real, mechanical buttons for a smartphone — a satisfying click and a zoomy strip. The microcontroller used in this device is the BGM111 Bluetooth LE module from Silicon Labs. It’s an extremely low-power module that is able to read a cap touch strip and a few button inputs. Power is provided by a 2032 coin cell, giving the entire device a low profile form factor (except for the MX switches, but whatever), and more than enough run time.

It should be noted that [Kyle] is building this as a solution to distracted driving. True, looking down to send a quick text while driving is the cause of thousands of deaths. However, while typing out a quick note with a T9 keyboard on your Nokia seems like it’s less dangerous, it’s really not. Doing anything while driving is distracted driving, and there are volumes of studies to back this up. Outside the intended use case, this is a fantastic project that uses a neat little Bluetooth module we don’t see much of, and there are some pretty cool applications of a tiny wireless mechanical keyboard with cap touch we can think of.

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Active Discussion About Passive Components

October 16, 2017 by 35 Comments

People talk about active and passive components like they are two distinct classes of electronic parts. When sourcing components on a BOM, you have the passives, which are the little things that are cheaper than a dime a dozen, and then the rest that make up the bulk of the cost. Diodes and transistors definitely fall into the cheap little things category, but aren’t necessarily passive components, so what IS the difference?

Continue reading “Active Discussion About Passive Components” →