Month: January 2018

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Hackaday Links: January 7, 2018

January 7, 2018 by 23 Comments

Whelp, Spectre and Meltdown are the tech news du jour right now, and everyone is wondering: what is the effect of this problem on real hardware in real server rooms? Epic Games patched their machines and found something shocking. The CPU utilization for one of their online services increased about 100%. We don’t know what this server is doing, or what this process is, but the Spectre and Meltdown patches will increase CPU load depending on the actual code running. This is bad for Epic — they now have to buy an entirely new server farm. This is doubly bad for Intel, and there is speculation of a class action suit floating around the darker corners of the Interwebs.

It is with a heavy heart that I must report the passing of John Young, the only person to have commanded four different classes of spacecraft (five if you include the lunar rover), including the first launch of the Space Shuttle. He was, simply, the most badass astronaut to ever live. Need proof of that? His heart rate during the launch of a Saturn V was seventy.

By the time this post is published, you’ll have less than twenty-four hours to submit your project to the Coin Cell Challenge. Get to it!

A short reminder that Shmoocon is a mere two weeks away. What is Shmoocon? A totally chill cyber/sec/hacker con at the Washington D.C. Hilton (yes, where Reagan was shot). We’ll be there, and we’re looking for some like-minded Hackaday peeps to chill out with. Want a meetup? Reply in the comments.

A few years ago, the ESP8266 appeared out of the blue in a few Chinese reseller’s web shops, and everything has been gravy since. Now there’s a new magic do-everything chip appearing on AliExpress and Taobao. It’s the RDA5981, a chip with an ARM Cortex M4 core, 32Mbit of Flash, 192k or user RAM, b/g/n WiFi, I2S, and enough peripherals to be useful. Given the support for a MIC, line in, MP3, WAV, WMA and AAC, it appears this is an all-in-one chip designed for Bluetooth speakers or some other audio application. You can find modules on Alibaba and a few breakout boards on Taobao.

According to my sources (the press releases that somehow slipped through the ‘CES’ filter on my email), the world’s fastest, smallest, biggest, least expensive, and newest drone is set to be unveiled at CES in Vegas this week.

Robotic Drive Train Is Nearly All 3D Printed

January 7, 2018 by 2 Comments

There are lots of ways to move a robot ranging from wheels, treads, legs, and even propellers through air or water. Once you decide on locomotion, you also have to decide on the configuration. One possible way to use wheels is with a swerve drive — a drive with independent motors and steering on each wheel. Prolific designer [LoboCNC] has a new version of his swerve drive on Thingiverse. The interesting thing is that it’s nearly all 3D printed.

You do need a few metal parts, a belt, two motors, and — no kidding — airsoft BBs, used as bearings. There are 3 parts you have to fabricate, which could take some work on a lathe, so it isn’t completely 3D printed.

[LoboCNC] points out that the assembly is lightweight and is not made for heavy robots. Apparently, though, his idea of lightweight is no more than 20 pounds per wheel, so that’s still pretty large in our book. The two motors allow for one motor to provide drive rotation while the other one — which includes an encoder — to steer. Of course, the software has to account for the effect of steering each wheel separately, but that’s another problem.

This robotic drivetrain is just thing for a car-like robot. If you are a little lonesome you could always print out ASPIR, instead. Or if you want an exotic 3D printed way to move things, you might get some inspiration from Zizzy. If you want a swerve drive that doesn’t require any machining or 3D printing, you might enjoy the video from another FIRST team, below.

Continue reading “Robotic Drive Train Is Nearly All 3D Printed” →

Afroman Teaches Intro To Servos, Builds Laser Turret

January 7, 2018 by 10 Comments

After a longish hiatus, we were pleased to see a new video from [Afroman], one of the most accessible and well-spoken teachers the internet has to offer. If you’re new to electronics, see the previous sentence and resolve to check out his excellent videos. The new one is all about servos, and it culminates in a simple build that provides a foundation for exploring robotics.

[Afroman] leaves no gear unturned in his tour de servo, which is embedded after the break. He explains the differences between open vs. closed loop motor systems, discusses the different sizes and types of servos available, and walks through the horns and pigtails of using them in projects. Finally, he puts this knowledge to use by building a laser turret based on a pan-tilt platform.

The Arduino-driven turret uses two micro servos controlled with pots to move by degrees in X/Y space. Interestingly, [Afroman] doesn’t program the board in the Arduino IDE using wiring. Instead, he uses an open-source microcontroller language/IDE called XOD that lets you code by building a smart sort of schematic from drag-and-drop components and logic nodes. Draw the connections, assign your I/O pin numbers, and XOD will compile the code and upload it directly to the board.

Continue reading “Afroman Teaches Intro To Servos, Builds Laser Turret” →

Scrap A Hard Drive, Build A Rotary Encoder

January 7, 2018 by 26 Comments

There’s something to be said for the feel of controls. Whether it’s the satisfying snap of a high-quality switch or the buttery touch of the pots on an expensive amplifier, the tactile experience of the controls you interact with says a lot about a device.

[GreatScott!] knows this, and rather than put up with the bump and grind of a cheap rotary encoder, he decided to find an alternative. He ended up exploring hard drive motors as encoders, and while the results aren’t exactly high resolution, he may be onto something. Starting with a teardown of some old HDDs — save those magnets! — [Scott!] found that the motors fell into either the four-lead or three-lead categories. Knowing that HDD motors are brushless DC motors, he reasoned that the four-lead motors had their three windings in Wye configuration with the neutral point brought out to an external connection. A little oscilloscope work showed the expected three-phase output when the motor hub was turned, with the leading and lagging phases changing as the direction of rotation was switched. Hooked to an Arduino, the motor made a workable encoder, later improved by sending each phase through a comparator and using digital inputs rather than using the Nano’s ADCs.

It looks like [GreatScott!]’s current setup only responds to a full rotation of the makeshift encoder, but we’d bet resolution could be improved. Perhaps this previous post on turning BLDC motors into encoders will help.

Continue reading “Scrap A Hard Drive, Build A Rotary Encoder” →

A Mini Stacker Arcade Cabinet

January 7, 2018 by 10 Comments

For [LumoW], what started as a school project turned into a passion project. He and his team made a hardware implementation of an arcade game called Stacker. Never heard of it? It’s pretty fun, kind of like an inverse Tetris. You can play the flash version here and see their mini arcade version after the break.

The game is based around the Mojo FPGA which the class required, and it’s programmed entirely in bitwise operators. It uses WS2812 RGB LEDs to represent the individual tower building blocks, and these are mounted on plywood in a matrix and separated into cells by a grid of foam board. After some trial and error, the team found the perfect shade of acrylic to diffuse the bright dots into glowing squares.

Since the game only needs one input, we don’t think [LumoW] should apologize at all for using the biggest, baddest button they could find. Besides, the game has that edge-of-your-seat action that can turn panic into heavy-handedness and cool DIY arcade games into shards of sadness.

Looking for something more advanced to do with an FPGA? Try your hand at vector games.

Continue reading “A Mini Stacker Arcade Cabinet” →

The Secret Of Twinkling Christmas Lights

January 7, 2018 by 26 Comments

With the holidays over, many of us are braving the elements to take down all those holiday lights. LED lights have largely taken over the market, but in some places, you can still get classic incandescent bulbs. There are some effects that LEDs can’t quite mimic yet. One of those is the magic of “twinkling” light sets, which [Alec Watson] explains in a Technology Connections video. Everyone has seen bulbs that flash, and strings that dim. But the twinkle effect until recently has been hard to describe.

Typical flashing bulbs use a bimetallic strip. As the filament of the bulb heats up, the strip bends, opening the circuit. Then the strip cools and closes the circuit again. Twinkling lights do exactly the opposite. The bimetallic strip shorts the bulb out rather than open the circuit. Twinkling sets also use a lot of bimetallic strip bulbs – typically every fifth bulb has a strip. The result of the bulbs being shorted out is that all be the bulbs in set see a higher voltage. This makes the entire strip shimmer in time with the flashing. That’s where the twinkling magic comes from.

It occurs to us that the voltage on the strip would be a great source of random seeds. Sure, you’d have to replace bulbs now and again, but how many people can say they get their random numbers from a set of Christmas lights?

If you’re curious how incandescent Christmas lights can blow and not take out the whole strip, check out this article about anti-fuses.

Continue reading “The Secret Of Twinkling Christmas Lights” →

3D Printed Propellers Take To The Skies

January 6, 2018 by 10 Comments

In the world of drones, propeller choice is key to performance. Selecting the right props can have a major effect on things like flight time, vibration, and a whole host of other factors. Thinking it might be fun to experiment, [RCLifeOn] decided to 3D print some props and head out for a flight.

The props are a fairly simple 3-bladed design, which were printed in both PETG and PLA. No major difference is noted between the two materials, and the quadcopter under test is able to fly with either. It was noted that the props perform particularly poorly in a crash, with all props failing even in the softest of crashes. We would recommend some eye (and body) protection when spinning these props up for the first time.

If you’re keen to try them out yourself, the STL file can be had here. The video notes that when printing 4 props, 2 must be reversed in the Y-axis to print a counter-rotating set of 4. The instructions used for creating propellers in Fusion3D are available here.

It’s a worthy experiment, and something we’d like to see more of. With a 3D printer, it’s possible to experiment with all manner of propeller designs, and we’d love to see the best and worst designs that are still capable of flight. We’ve also seen 3D printed props before, like this effort from [Anton].