Hackaday Prize Entry: Oscilloscope For The Masses

June 15, 2017 by Bryan Cockfield 38 Comments

If you head down to your local electronics supply shop (the Internet), you can pick up a quality true-RMS multimeter for about $100 that will do almost everything you will ever need. It won’t be able to view waveforms, though; this is the realm of the oscilloscope. Unlike the multimeter’s realistic price point, however, a decent oscilloscope is easily many hundreds, and often thousands, of dollars. While this is prohibitively expensive for most, the next entry into the Hackaday Prize seeks to bring an inexpensive oscilloscope to the masses.

The multiScope is built by [Vítor] and is based on the STM32-O-Scope which is built around a STM32F103C8T6 microcontroller. This particular chip was chosen because of its high clock speed and impressive analog-to-digital resolution, which are two critical specifications for any oscilloscope. This particular scope has an inductance meter built-in as well, which is another feature which your otherwise-capable multimeter probably doesn’t have.

New features continue to get added to this scope by [Vítor]. Most recently he’s added features which support negative voltages and offsets. His particular scope is built inside of a model car, too, but we believe this to be an optional feature.

Imaginary AC Circuits Aren’t Really Complex

June 15, 2017 by Al Williams 32 Comments

If you have ever read advanced textbooks or papers about electronics, you may have been surprised to see the use of complex numbers used in the analysis of AC circuits. A complex number has two parts: a real part and an imaginary part. I’ve often thought that a lot of books and classes just kind of gloss over what this really means. What part of electricity is imaginary? Why do we do this?

The short answer is phase angle: the time delay between a voltage and a current in a circuit. How can an angle be a time? That’s part of what I’ll need to explain.

First, consider a resistor. If you apply a voltage to it, a certain current will flow that you can determine by Ohm’s law. If you know the instantaneous voltage across the resistor, you can derive the current and you can find the power–how much work that electricity will do. That’s fine for DC current through resistors. But components like capacitors and inductors with an AC current don’t obey Ohm’s law. Take a capacitor. Current only flows when the capacitor is charging or discharging, so the current through it relates to the rate of change of the voltage, not the instantaneous voltage level.

That means that if you plot the sine wave voltage against the current, the peak of the voltage will be where the current is minimal, and the peak current will be where the voltage is at zero. You can see that in this image, where the yellow wave is voltage (V) and the green wave is current (I). See how the green peak is where the yellow curve crosses zero? And the yellow peak is where the green curve crosses zero?

These linked sine and cosine waves might remind you of something — the X and Y coordinates of a point being swept around a circle at a constant rate, and that’s our connection to complex numbers. By the end of the post, you’ll see it isn’t all that complicated and the “imaginary” quantity isn’t imaginary at all.

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Hacked Car Axle Yields Custom 90° Gearbox

June 15, 2017 by Dan Maloney 26 Comments

Need a sturdy angle gearbox to handle power transmission for your next big project? Why not harvest a rear axle from a car and make one yourself?

When you think about it, the axle of a rear-wheel drive vehicle is really just a couple of 90° gearboxes linked together internally, and a pretty sturdy assembly that’s readily available for free or on the cheap. [Donn DIY]’s need for a gearbox to run a mower lead him to a boneyard for the raw material. The video below shows some truly impressive work with that indispensable tool of hardware hackers, the angle grinder. Not only does he amputate one of the half axles with it, he actually creates almost perfect splines on the remaining shortened shaft. Such work is usually done on a milling machine with a dividing head and an end mill, but [DonnDIY]’s junkyard approach worked great. Just goes to show how much you can accomplish with what you’ve got when you have no choice.

We’re surprised to not see any of [DonnDIY]’s projects featured here before, as he seems to have quite a body of hacks built up. We hope to feature some more of his stuff soon, but in the meantime, you can always check out some of the perils and pitfalls of automotive differentials.

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Amazon Echo Show

June 15, 2017 by Adam Fabio 22 Comments

Back in May, Amazon announced the Echo Show, its new version of Alexa with a 7 inch touchscreen. The Echo Show is an interesting device, but will the great unwashed masses pony up $229 to buy the show? That’s $50 more than the original Echo, or $180 more than the Echo Dot. With 5.2 million units sold in 2016, Echo has been a resounding success. This has been in part due to Amazon’s open approach to the API. Anyone can build an Alexa compatible device using a Raspberry Pi. Google has (finally) followed suit with their Home device.

It’s not just the hardware that is accessible. Skills Kit, the programmer interface for extending Echo’s functionality, is also open. At CES this year, Alexa was the belle of the ball. Third party devices are being introduced from all corners, all of them connecting to Amazon’s cloud and responding to the “Alexa” keyword.

The Echo Show takes the family in a new direction. Adding a touch screen gives the user a window on the the world not available with voice interactions. Echo Show also includes a camera, which opens up a whole new set of privacy and security questions. Amazon touts it as a device for viewing security cameras, watching YouTube videos, and making video calls. This puts Echo Show dangerously close to the internet appliance category, essentially a barren wasteland littered with the corpses of previous devices. Does anyone remember when Palm tried this with the 3Com Ergo Audrey? How about the i-Opener? Will Alexa persevere and succeed where others have failed? A lot of it will depend on the third party developers, and how Amazon treats them.

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New Take On The Binary Clock

June 15, 2017 by Bryan Cockfield 10 Comments

By now it might seem like there’s no new way to build a binary clock. It’s one of the first projects many build to try out their first soldering irons, so it’s a well-traveled path. Every now and then, however, there’s a binary clock that takes a different approach, much like [Stephen]’s latest project which he calls the byte clock.

The clock works by dividing the 24-hour day into half and using an LED to represent this division, which coincidentally works out to representing AM or PM. The day is divided in half over and over again, with each division getting its own LED. In order to use this method to get one-second resolution it would need 16 LEDs, but since that much resolution isn’t too important for a general-use clock, [Stephen] reduced this to eight.

Additionally, since we’re in the Internet age, the clock has built-in WiFi courtesy of a small version of Python called WiPy which runs on its own microcontroller. A real-time clock rounds out the build and makes sure the clock is as accurate as possible. Of course an RTC might not have the accuracy as some other clocks, but for this application it certainly gets the job done.

Need To Hold Something? Build A Custom Vise

June 15, 2017 by John Baichtal 15 Comments

The only thing better than making a cool project is making a cool project that helps make more projects! Case in point, [Greg Stephens] and [Alex] wanted to colorize steel bearings for use in a Newton’s Cradle desk toy. After trying out a torch and not liking it, [Greg] and [Alex] decided to build custom aluminum vise to hold the sphere while it sits in the magnetic induction forge.

Their vise–they call it the Maker’s Vise0–isn’t just a one-off project to help make the cradle. [Alex] and [Greg] aspire to create a tool useable for a wide variety of projects. They wanted it to be oil-less and it had to be customizable. Ideally it would also have an acceptable grip strength, be easy to use, and look good on the bench.

[Greg] and [Alex] have set up a Hackaday.io project, and their logs show a lot of progress with two finished iterations of the vise and a variety of 3D-printed and cast parts to go with. Recently they brought in a 2,000-lb. load test and tested it on their vise collection, including the two prototypes. Version one rated at 500 lbs. reasonable clamping pressure–meaning they didn’t exert themselves to max out the pressure. Version two sits at 800 lbs., still nothing like a desk vise but far stronger than a Panavise, for instance.

Their magnetic induction forge project was also a success, with the team able to quickly change the color of a steel ball. Check out a video after the break…

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You Are Go For FPGA!

June 14, 2017 by Al Williams 39 Comments

Reconfigure.io is accepting beta applications for its environment to configure FPGAs using Go. Yes, Go is a programming language, but the software converts code into FPGA constructs, so you don’t need Verilog or VHDL. Since Go supports concurrent routines and channels for synchronization and communications, the parallel nature of the FPGA should fit well.

According to the project’s website, the tool also allows you to reconfigure the FPGA on the fly using a cloud-based build and deploy system. There isn’t much detail yet, unless you get accepted for the alpha. They claim they’ll give priority to the most interesting use cases, so pitching your blinking LED project probably isn’t going to cut it. There is a bit more detail, however, on their GitHub site.

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