Testing Brushless Motors with a Scope (or a Meter)

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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, …read more

Control System Fundamentals by Video

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If you’ve had the classic engineering education, you probably have a hazy recollection of someone talking about control theory. If you haven’t, you’ve probably at least heard of PID controllers and open loop vs closed loop control. If you don’t know about control theory or even if you just want a refresher, [Brian Douglas] has an excellent set of nearly 50 video lectures that will give you a great introduction to the topic. You can watch the first lecture, below.

You might think that control systems are only useful in electronics when you are trying to control a process like …read more

Sacrificial Bridge Avoids 3D Printed Supports

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[Tommy] shares a simple 3D printing design tip that will be self-evident to some, but a bit of a revelation to others: the concept of a sacrificial bridge to avoid awkward support structures. In the picture shown, the black 3D print has small bridges and each bridge has a hole. The purpose of these bits is to hold a hex nut captive in the area under the bridge; a bolt goes in through the round hole in the top.

Readers familiar with 3D printing will see right away that printing the bridges might be a problem. When a printer gets …read more

Click Your Heels Thrice, Hail a Cab Home

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If Dorothy from The Wizard of Oz were to wake up in 2017, with her magic Ruby Slippers on her feet, she’d probably believe she had woken up in a magical world. But modern folks will need a little more magic to impress them. Like Clicking your heels thrice to get home with these Uber ruby slippers. [Hannah Joshua] was tasked by her employer to build a quirky maker project. She got an idea when a friend complained about having trouble hailing a cab at the end of a hard day at work.

[Hannah] started with ruby colored slippers with …read more

Spare RPi? You Have a Currency Trading Platform

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While Bitcoin and other altcoins are all the rage these days, there is still a lot of activity in the traditional currency exchanges. Believe it or not, there’s money to be made there as well, although it rarely makes fanciful news stories like cryptocurrency has been. Traditional currency trading can be done similar to picking stocks, but if you’d rather automate your particular trading algorithm you can set up a Raspberry Pi to make money by trading money.

This particular project by [dmitry] trades currency on the Forex exchange using an already-existing currency trading software package called MetaTrader. This isn’t …read more

Hackaday Prize Entry: Playing With USB Power Delivery

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USB Power Delivery is the technology that’s able to pump 100 Watts down a USB cable. It’s been around for half a decade now, but only in the last few years have devices and power supplies supporting USB PD shown up on the market. This is a really interesting technology, and we can’t wait to see the outcome of people messing around with five amps flowing through a cable they picked up at the dollar store, but where are the DIY solutions to futz around with USB PD?

For his Hackaday Prize entry, [Clayton] is doing just that. He’s built …read more

Stripping 3D Printed Gears for Science

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While 3D printing is now well on its way to becoming “boring” in the same way that a table saw or lathe is, there was a time when the media and even some early adopters would have told you that the average desktop 3D printer was perhaps only a few decades behind the kind of replicator technology we saw on the Enterprise. But as the availability of these machines increased and more people got to see one up close, reality sunk in pretty quickly.

Many have dismissed the technology as little more than a novelty, and even within the 3D …read more

TeensyStep – Fast Stepper Library for Teensy

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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 …read more

Snazzy Balun Lets Ham Use Off-The-Shelf Coax

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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 ?, whereas the ham world is geared to 50 ?. Not willing to waste a bounty of free coax, one ham built a custom 1:1 current balun for a 75 ? 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 …read more

Dubai Police Test Quadcopter Motorcycle

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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 …read more

Hackaday Prize Entry: Giving Phones Their Tactile Buttons Back

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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, …read more

Active Discussion About Passive Components

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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?

Resistors, Capacitors, Inductors, Transformers, Diodes*, and Memristors

That’s the list. Those are your passive components. Well, it’s not that easy. Also add in a bunch of types of …read more

The Fine Art of Heating And Cooling Your Beans

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They say that if something is worth doing, it’s worth doing right. Those are good words to live by, but here at Hackaday we occasionally like to adhere to a slight variation of that saying: “If it’s worth doing, it’s worth overdoing”. So when we saw the incredible amount of work and careful research [Rob Linnaeus] was doing just to roast coffee beans, we knew he was onto something.

The heart of his coffee roaster is a vortex chamber with an opening on the side for a standard heat gun, and an aperture in the top where an eight cup …read more

Inside Two-Factor Authentication Apps

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Passwords are in a pretty broken state of implementation for authentication. People pick horrible passwords and use the same password all over the place, firms fail to store them correctly and then their databases get leaked, and if anyone’s looking over your shoulder as you type it in (literally or metaphorically), you’re hosed. We’re told that two-factor authentication (2FA) is here to the rescue.

Well maybe. 2FA that actually implements a second factor is fantastic, but Google Authenticator, Facebook Code Generator, and any of the other app-based “second factors” are really just a second password. And worse, that second password …read more

Why Not Expose Your PCBs Through An LCD?

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Most people who have dabbled in the world of electronic construction will be familiar in some form with the process of producing a printed circuit board by exposing a UV sensitive coating through a transparent mask, before moving on to etching. Older readers will have created their masks by hand with crêpe paper tape on acetate, while perhaps younger ones started by laser-printing from their CAD package.

How about a refinement of the process, one which does away with the acetate mask entirely? [Ionel Ciobanuc] may have the answer, in the form of an exposure through an LCD screen. The …read more

LEGO Row Boat Is The Poolside Companion You Didn’t Know You Needed

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Maybe it’s the upbeat music, or the views of a placid lake at sunset, or perhaps it’s just seeing those little plastic rods pumping away with all their might. Whatever the reason may be, the video [Vimal Patel] posted of his little remote controlled LEGO row boat cruising around on the open water is sure to put a smile on the face of even the most jaded hacker.

[Vimal] tells us that his creation is made up of over 140 unmodified LEGO parts, and is controlled over Bluetooth which connects to an app on his phone. While we would like …read more

Xero Alto CRTs Needed a Tiny Lightbulb to Function

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In the real world, components don’t work like we imagine they do. Wires have resistance, resistors have inductance, and capacitors have resistance. However, some designers like to take advantage of those imperfections, something our old friend [Ken Shirriff] noted when he was restoring the CRT of a Xerox Alto.

[Ken] tried to connect a Xerox monitor to the Alto and — since it was almost as old as the Alto — he wasn’t surprised that it didn’t work. What did surprise him, though, is that when he turned the monitor off, a perfect picture appeared for just a split second …read more

Hackaday Links: October 15, 2017

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For the last few months we’ve been running The Hackaday Prize, a challenge for you to build the best bit of hardware. Right now — I mean right now — you should be finishing up your project, crossing your t’s and dotting your lowercase j’s. The last challenge in the Prize ends tomorrow. After that, we’re going to pick 20 finalists for the Anything Goes challenge, then send the finalists off to our fantastic team of judges. Time to get to work! Make sure your project meets all the requirements!

It’s been a few weeks, so it’s time to start …read more

Cheap 3D Printers Make Cheaper(er) Bioprinters

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In case you missed it, prices on 3D printers have hit an all time low. The hardware is largely standardized and the software is almost exclusively open source, so it makes sense that eventually somebody was going to start knocking these things out cheap. There are now many 3D printers available for less than $300 USD, and a few are even dipping under the $200 mark. Realistically, this is about as cheap as these machines are ever going to get.

A startup by the name of 3D Cultures has recently started capitalizing on the availability of these inexpensive high-precision three …read more

Cheap 3D Printers Make Cheaper(er) Bioprinters

See the original posting on Hackaday

In case you missed it, prices on 3D printers have hit an all time low. The hardware is largely standardized and the software is almost exclusively open source, so it makes sense that eventually somebody was going to start knocking these things out cheap. There are now many 3D printers available for less than $300 USD, and a few are even dipping under the $200 mark. Realistically, this is about as cheap as these machines are ever going to get.

A startup by the name of 3D Cultures has recently started capitalizing on the availability of these inexpensive high-precision three …read more

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