The BeagleBone Blue – Perfect For Robots

March 15, 2017 by Brian Benchoff 45 Comments

There’s a new BeagleBone on the block, and it’s Blue. The BeagleBone Blue is built for robots, and it’s available right now.

If a cerulean BeagleBone sounds familiar, you’re not wrong. About a year ago, the BeagleBone Blue was introduced in partnership with UCSD. This board was meant for robotics, and had the peripherals to match. Support for battery charging was included, as well as motor drivers, sensor inputs, and wireless. If you want to put Linux on a moving thingy, there are worse choices.

The newly introduced BeagleBone Blue is more or less the same. A 9-axis IMU, barometer, motor driver, quad encoder sensor, servo driver, and a balancing LiPo charger are all included. The difference in this revision is the processor. That big square of epoxy in the middle of the board is the Octavo Systems OSD3358, better known as a BeagleBone on a chip. This is the first actual product we’ve seen using this neat chip, but assuredly not the last – a few people are working on stuffing this chip onto a board that fits in mini Altoids tins.

How An Oscilloscope Probe Works, And Other Stories

March 15, 2017 by Jenny List 29 Comments

The oscilloscope is probably the most versatile piece of test equipment you can have on your electronics bench, offering a multitude of possibilities for measuring timing, frequency and voltage as well as subtleties in your circuits revealed by the shape of the waveforms they produce.

On the front of a modern ‘scope is a BNC socket, into which you can feed your signal to be investigated. If however you simply hook up a co-axial BNC lead between source and ‘scope, you’ll immediately notice some problems. Your waveforms will be distorted. In the simplest terms your square waves will no longer be square.

Why is this? Crucial to the operation of an oscilloscope is a very high input impedance, to minimise current draw on the circuit it is investigating. Thus the first thing that you will find behind that BNC socket is a 1 megohm resistor to ground, or at least if not a physical resistor then other circuitry that presents its equivalent. This high resistance does its job of presenting a high impedance to the outside world, but comes with a penalty. Because of its high value, the effects of even a small external capacitance can be enough to create a surprisingly effective low or high pass filter, which in turn can distort the waveform you expect on the screen.

The answer to this problem is to be found in your oscilloscope probe. It might seem that the probe is simply a plug with a bit of wire to a rigid point with an earth clip, but in reality it contains a simple yet clever mitigation of the capacitance problem.

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This WAV File Can Confuse Your Fitbit

March 15, 2017 by Jenny List 30 Comments

As the devices with which we surround ourselves become ever more connected to the rest of the world, a lot more thought is being given to their security with respect to the internet. It’s important to remember though that this is not the only possible attack vector through which they could be compromised. All devices that incorporate sensors or indicators have the potential to be exploited in some way, whether that is as simple as sniffing the data stream expressed through a flashing LED, or a more complex attack.

Researchers at the University of Michigan and the University of South Carolina have demonstrated a successful attack against MEMS accelerometers such as you might find in a smartphone. They are using carefully crafted sound waves, and can replicate at will any output the device should be capable of returning.

MEMS accelerometers have a microscopic sprung weight with protruding plates that form part of a set of capacitors. The displacement of the weight due to acceleration is measured by looking at the difference between the capacitance on either side of the plates.

The team describe their work in the video we’ve put below the break, though frustratingly they don’t go into quite enough detail other than mentioning anti-aliasing. We suspect that they vibrate the weight such that it matches the sampling frequency of the sensor, and constantly registers a reading at a point on its travel they can dial in through the phase of their applied sound. They demonstrate interference with a model car controlled by a smartphone, and spurious steps added to a Fitbit. The whole thing is enough for the New York Times to worry about hacking a phone with sound waves, which is rather a predictable overreaction that is not shared by the researchers themselves.

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Arpeggio – The Piano SuperDroid

March 14, 2017 by Adil Malik 43 Comments

I never had the musical talent in me. Every now and then I would try to pick up a guitar or try and learn the piano, romanticising a glamorous career out of it at some point. Arpeggio – the Piano SuperDroid (YouTube, embedded below) sure makes me glad I chose a different career path. This remarkable machine is the brain child of [Nick Morris], who spent two years building it.

Although there are no detailed technical descriptions yet, at its heart this handsome robot consists of a set of machined ‘fingers’ connected to a set of actuators — most likely solenoids . The solenoids are controlled by proprietary software that combines traditional musical data with additional parameters to accurately mimic performances by your favourite pianists, right in your living room. Professional pianists, who were otherwise assuming excellent job security under Skynet, clearly have to reconsider now.

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Hands-On Nvidia Jetson TX2: Fast Processing For Embedded Devices

March 14, 2017 by Brian Benchoff 74 Comments

The review embargo is finally over and we can share what we found in the Nvidia Jetson TX2. It’s fast. It’s very fast. While the intended use for the TX2 may be a bit niche for someone building one-off prototypes, there’s a lot of promise here for some very interesting applications.

Last week, Nvidia announced the Jetson TX2, a high-performance single board computer designed to be the brains of self-driving cars, selfie-snapping drones, Alexa-like bots for the privacy-minded, and other applications that require a lot of processing on a significant power budget.

This is the follow-up to the Nvidia Jetson TX1. Since the release of the TX1, Nvidia has made some great strides. Now we have Pascal GPUs, and there’s never been a better time to buy a graphics card. Deep learning is a hot topic that every new CS grad wants to get into, and that means racks filled with GPUs and CUDA cores. The Jetson TX1 and TX2 are Nvidia’s strike at embedded deep learning, or devices that need a lot of processing power without sucking batteries dry.

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Tea Making The Mechanical Way

March 13, 2017 by Jenny List 34 Comments

For some of those who are aficionados of the drink, tea making can be serious business. For them, strong, black, leaf tea left for ages to stew in a stained teapot that would strip the hairs off your chest (like it should be made) just won’t do. These beverage anarchists demand a preparation process of careful temperature regulation and timing, and for some reason repeatedly dunking a teabag in the water.

For them, [Dorian Damon] has an automated solution to getting the crucial dunking process right. He’s made an automatic tea bag dunker. The teabag is mounted on a slide operated by a crank, and the crank is driven through a pair of bicycle hubs. Motive power comes from a mains shaded-pole motor, an unusual bi-directional one of which he only uses one side. He measured his personal dunking rate at about 50 per minute, so he only needed a 4:1 reduction to match the motor at 200 RPM.

The resulting machine will happily dunk his tea bag at that rate for as long as it’s left switched on. He’s put a few videos up, of which we’ve posted one below the break.

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The God Particle

March 13, 2017 by Will Sweatman 56 Comments

The Greek philosopher Plato is well known for his allegories and metaphors. Of particular interest is his Allegory of the Cave, which appeared in The Republic, written around 380BCE. In it, Plato describes a group of prisoners which are chained to a wall within a cave, and have been all of their lives. They have no direct interaction with the world outside of the cave. They only know of the world via shadows that are cast on the wall opposite of them. For the prisoners, the shadows are their reality. Though you and I know the shadows are only a very low-resolution representation of that reality.

standard_01 — Plato’s “Allegory of the Cave”, drawing by Markus Maurer

Theoretical physicist Steven Weinberg, a Nobel Prize winner who works out of the University of Texas at Austin, once likened himself to a prisoner in Plato’s cave. We are forever chained to this cave by the limitations in measurements we can make and experiments we can perform. All that we can know are shadows of the reality that exists in the sub-atomic world. We can see the shadowy figures lurking in our math and as wisps of misty vapor trails in our cloud chambers. We attempt to pierce the veil with the power of our imagination and draw nifty looking charts and animations depicting what our mind’s eye thinks it can see. But in the end, we are all trapped in a cave… staring at shadows. Reflections of a reality we can never truly know.

In our last Quantum Mechanics article, we introduced you to the idea of quantum electrodynamics, or to put it more simply — quantum field theory. In this article, we’re going to explore how QED lead to the prediction and eventual confirmation of something known as the Higgs Boson, also known as the God Particle. As usual, we’ll aim to keep things as simple as possible, allowing anyone with a curious mind to know what this God particle talk is all about. Like so many things in the quantum world, it all started with an unexpected outcome…

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