Hoverboard Reborn For Electric Rollerblading

October 31, 2017 by Dan Maloney 8 Comments

Rollerblading is fun, but who needs all that pesky exercise? Wouldn’t strapping on the blades be so much more tempting if you had an electric pusher motor to propel you along your way?

We have to admit that we raised a wary eyebrow as we first watched [MakerMan]’s video below. We thought it was going to be just another hoverboard hack at first, but as we watched, there were some pretty impressive fabrication skills on display. Yes, the project does start with tearing into a defunct hoverboard for parts, primarily one wheel motor and the battery pack. But after that, [MakerMan] took off on a metalworking tear. Parts of the hoverboard chassis were attached to a frame built from solid bar stock — we’ll admit never having seen curves fabricated in quite that way before. The dead 18650 in the battery pack was identified and replaced, and a controller from an e-bike was wired up. Fitted with a thumb throttle and with a bit of padding on the crossbar, it’s almost a ride-upon but not quite. It seems to move along at quite a clip, even making allowances for the time-compression on the video.

We’ve seen lots of transportation hacks before, from collapsible longboards to steam-powered bicycles, but this one is pretty unique.

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Everything Worth Knowing About Lockwire

October 20, 2017 by Brian McEvoy 29 Comments

We were tipped off to an older video by [AgentJayZ] which demonstrates the proper use of lockwire also known as ‘safety wire.’ In high vibration operations like jet engines, street racers, machine guns, and that rickety old wheelchair you want to turn into a drift trike, a loose bolt can spell disaster. Nylon fails under heat and mechanical lock washers rely on friction which has its limits. Safety wire holds up under heat and resists loosening as long as the wire is intact.

Many of our readers will already be familiar with lockwire since it is hardly a cutting-edge technology — unless you are talking about the cut ends of lockwire which [AgentJayZ] warns will slice up your fingers if you aren’t mindful. Some of us Jacks-or-Jills-of-all-trades, with knowledge an inch deep and a mile wide, may not realize all there is to lockwire. In the first eight minutes, we’ll bet that you’ve gotten at least two inches deep into this subject.

[Editor’s Note: an inch is exactly 25.4 mm, if the previous metaphors get lost in translation. A mile is something like 2,933.333 Assyrian cubits. Way bigger than an inch, anyway.]

Now, those pesky loose bolts which cost us time and sighs have a clear solution. For the old-hands, you can brush up on lockwire by watching the rest of video after the break.

Thank you [Keith Olson] for the tip, and we’ll be keeping an eye on [AgentJayZ] who, to date, has published over 450 videos about jet engines.

If safety isn’t your highest priority, consider this jet engine on a bicycle or marvel at the intricacies of a printable jet engine.

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Testing Brushless Motors With A Scope (or A Meter)

October 18, 2017 by Al Williams 18 Comments

Brushless motors have a lot of advantages over traditional brushed motors. However, testing them can be a bit of a pain. Because the resistance of the motor’s coils is usually very low, a standard resistance check isn’t likely to be useful. Some people use LC meters, but those aren’t as common as a multimeter or oscilloscope. [Nils Rohwer] put out two videos — one two years ago and one recently — showing how to test a brushless motor with a multimeter or scope. Oh, you do need one other thing: a drill.

You don’t have to drill into the motor, instead you use the drill to spin the motor’s shaft. Since a motor and a generator are about the same thing, you can read the voltages produced by the spinning motor and determine if it is good or not. The first video shows the technique and the second, more recent video shows a scope reading a bad motor. You can see both videos, below.

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TeensyStep – Fast Stepper Library For Teensy

October 17, 2017 by Anool Mahidharia 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” →

Sparky, The Electric Boat

September 15, 2017 by Bryan Cockfield 13 Comments

They say the two best days of a boat owner’s life are the day that they buy the boat and the day they sell it. If you built your boat from scratch though, you might have a few more good days than that. [Paul] at [ElkinsDIY] is no stranger to building boats, but his other creations are a little too heavy for him to easily lift, so his latest is a fully electric, handmade boat that comes in at under 30 pounds and is sure to provide him with many more great days.

While the weight of the boat itself is an improvement over his older designs, this doesn’t include the weight of the batteries and the motor. To increase buoyancy to float this extra weight he made the boat slightly longer. A tiller provides steering and a trolling motor is used for propulsion. As of this video, the boat has a slight leak, but [Paul] plans to shore this up as he hammers out the kinks.

The boat is very manageable for one person and looks like a blast for cruising around the local lakes. Since it’s built with common tools and materials virtually anyone should be able to build something similar, even if you don’t have this specific type of plastic on hand. And, while this one might not do well in heavy wind or seas, it’s possible to build a small one-person boat that can cross entire oceans.

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Open Source High Power EV Motor Controller

September 11, 2017 by Anool Mahidharia 34 Comments

For anyone with interest in electric vehicles, especially drives and control systems for EV’s, the Endless-Sphere forum is the place to frequent. It’s full of some amazing projects covering electric skateboards to cars and everything in between. [Marcos Chaparro] recently posted details of his controller project — the VESC-controller, an open source controller capable of driving motors up to 200 hp.

[Marcos]’s controller is a fork of the VESC by [Benjamin Vedder] who has an almost cult following among the forum for “creating something that all DIY electric skateboard builders have been longing for, an open source, highly programmable, high voltage, reliable speed controller to use in DIY eboard projects”. We’ve covered several VESC projects here at Hackaday.

While [Vedder]’s controller is aimed at low power applications such as skate board motors, [Marcos]’s version amps it up several notches. It uses 600 V 600 A IGBT modules and 460 A current sensors capable of powering BLDC motors up to 150 kW. Since the control logic is seperated from the gate drivers and IGBT’s, it’s possible to adapt it for high power applications. All design files are available on the Github repository. The feature list of this amazing build is so long, it’s best to head over to the forum to check out the nitty-gritty details. And [Marcos] is already thinking about removing all the analog sensing in favour of using voltage and current sensors with digital outputs for the next revision. He reckons using a FPGA plus flash memory can replace a big chunk of the analog parts from the bill of materials. This would eliminate tolerance, drift and noise issues associated with the analog parts.

[Marcos] is also working on refining a reference design for a power interface board that includes gate drivers, power mosfets, DC link and differential voltage/current sensing. Design files for this interface board are available from his GitHub repo too. According to [Marcos], with better sensors and a beefier power stage, the same control board should work for motors in excess of 500 hp. Check out the video after the break showing the VESC-controller being put through its paces for an initial trial.

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How Low-Power Can You Go?

September 1, 2017 by James Hobson 28 Comments

[lasersaber] has a passion: low-power motors. In a bid to challenge himself and inspired by betavoltaic cells, he has 3D printed and built a small nuclear powered motor!

This photovoltaic battery uses fragile glass vials of tritium extracted from keychains and a small section of a solar panel to absorb the light, generating power. After experimenting with numerous designs, [lasersaber] went with a 3D printed pyramid that houses six coils and three magnets, encapsulated in a glass cloche and accompanied by a suitably ominous green glow.

Can you guess how much power and current are coursing through this thing? Guess again. Lower. Lower.

Under 200mV and 20nA!

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