[Ben Krasnow] Gasses MEMS Chips, For Science

November 20, 2018 by Dan Maloney 61 Comments

Why in the world does helium kill iPhones and other members of the Apple ecosystem? Enquiring minds want to know, and [Ben Krasnow] has obliged with an investigation of the culprit: the MEMS oscillator. (YouTube, embedded below.)

When we first heard about this, courtesy in part via a Hackaday post on MRI-killed iPhones, we couldn’t imagine how poisoning a micro-electromechanical system (MEMS) part could kill a phone. We’d always associated MEMS with accelerometers and gyros, important sensors in the smartphone suite, but hardly essential. It turns out there’s another MEMS component in many Apple products: an SiT 1532 oscillator, a tiny replacement for quartz crystal oscillators.

[Ben] got a few from DigiKey and put them through some tests in a DIY gas chamber. He found that a partial pressure of helium as low as 2 kPa, or just 2% of atmospheric pressure, can kill the oscillator. To understand why, and because [Ben] has a scanning electron microscope, he lapped down some spare MEMS oscillators to expose their intricate innards. His SEM images are stunning but perplexing, raising questions about how such things could be made which he also addresses.

The bottom line: helium poisons MEMS oscillators in low enough concentrations that the original MRI story is plausible. As a bonus, we now understand MEMS devices a bit better, and have one more reason never to own an iPhone.

Continue reading “[Ben Krasnow] Gasses MEMS Chips, For Science” →

How’s A Gyro Work?

November 15, 2018 by Al Williams 25 Comments

It wasn’t long ago that a gyro — or gyroscope — was an exotic piece of electronics gear. Most of us only saw them as children’s toys that would balance on your finger. That’s changed, though, thanks to microelectronics. Now your game controller, your phone, and your drone all probably use little ICs that are actually three-axis gyroscopes. Ever wonder how they work and what they do? [RCModelReviews] has a video that covers three kinds of gyros: old mechanical gyros, modern MEMS gyros, and even an exotic laser-based gyro. (YouTube, embedded below.)

Gyroscopes allow you to detect orientation by detecting linear forces on a rotating element. They are used in everything from spacecraft to submarines. The device has many origins dating back to antiquity. But the modern gyro showed up around 1800 or so. The children’s toy appeared in 1917 and is still made today.

Continue reading “How’s A Gyro Work?” →

Helium Can Stop Your IPhone — Maybe Other MEMS, Too

October 31, 2018 by Al Williams 115 Comments

Sometimes hacking isn’t as much about building something, it’s about getting to the root of a particularly difficult problem. [Erik Wooldrige] was facing a problem like that. He’s a system specialist at a hospital near Chicago. Suddenly a bunch of iPhones and Apple watches were failing or glitching. The only thing anyone could think of was the recent install of an MRI machine.

Sure, an MRI machine can put out some serious electromagnetic pulses, but why would that only affect Apple products? Everything else in the hospital, including Android phones, seemed to be OK. But about 40 Apple devices were either dead or misbehaving.

Continue reading “Helium Can Stop Your IPhone — Maybe Other MEMS, Too” →

Freak Out Your Smartphone With Ultrasound

July 17, 2018 by Tom Nardi 13 Comments

There’s a school of thought that says complexity has an inversely proportional relation to reliability. In other words, the smarter you try to make something, the more likely it is to end up failing for a dumb reason. As a totally random example: you’re trying to write up a post for a popular hacking blog, all the while yelling repeatedly for your Echo Dot to turn on the fan sitting three feet away from you. It’s plugged into a WeMo Smart Plug, so you can’t even reach over and turn it on manually. You just keep repeating the same thing over and over in the sweltering July heat, hoping your virtual assistant eventually gets the hint. You know, something like that. That exact scenario definitely has never happened to anyone in the employ of this website.

So it should come as no surprise that the more sensors we pack into devices, the more potential avenues of failure we open up. [Julio Della Flora] writes in to tell us of some interesting experiments he’s been performing with the MEMS gyroscope in his Xiaomi MI5S Plus smartphone. He’s found that with a function generator and a standard speaker, he’s able to induce false sensor readings.

Now it should be said, [Julio] is not claiming to be the first person to discover that ultrasonic sound can confuse MEMS gyroscopes and accelerometers. At Black Hat 2017, a talk was given in which a “Sonic Gun” was used to do things like knock over self-balancing robots using the same principle. The researchers were also able to confuse a DJI Phantom drone, showing that the technique has the potential to be weaponized in the real-world.

It’s interesting to see more validation that not only is this a continuing issue with consumer devices, but that it doesn’t necessarily take expensive or exotic hardware to execute. Yet another reason to take ultrasound seriously as a potential threat.

Continue reading “Freak Out Your Smartphone With Ultrasound” →

Roll Up Your Sleeve, Watch A Video With This Smart Watch Forearm Projector

April 25, 2018 by Dan Maloney 35 Comments

We’re all slowly getting used to the idea of wearable technology, fabulous flops like the creepy Google Glass notwithstanding. But the big problem with tiny tech is in finding the real estate for user interfaces. Sure, we can make it tiny, but human fingers aren’t getting any smaller, and eyeballs can only resolve so much fine detail.

So how do we make wearables more usable? According to Carnegie-Mellon researcher [Chris Harrison], one way is to turn the wearer into the display and the input device (PDF link). More specifically, his LumiWatch projects a touch-responsive display onto the forearm of the wearer. The video below is pretty slick with some obvious CGI “artist’s rendition” displays up front. But even the somewhat limited displays shown later in the video are pretty impressive. The watch can claim up to 40-cm² of the user’s forearm for display, even at the shallow projection angle offered by a watch bezel only slightly above the arm — quite a feat given the irregular surface of the skin. It accomplishes this with a “pico-projector” consisting of red, blue, and green lasers and a pair of MEMS mirrors. The projector can adjust the linearity and brightness of the display to provide a consistent image across the uneven surface. An array of 10 time-of-flight sensors takes care of watching the display area for touch input gestures. It’s a fascinating project with a lot of potential, but we wonder how the variability of the human body might confound the display. Not to mention the need for short sleeves year round.

Need some basics on the micro-electrical mechanic systems (MEMS) behind the pico-projector in this watch? We’ve got a great primer on these microscopic machines.

Continue reading “Roll Up Your Sleeve, Watch A Video With This Smart Watch Forearm Projector” →

Color Organ Dress, A Wearable With Audio Feedback

January 20, 2018 by Jenny List 5 Comments

There is a huge amount of interest among our community in wearable electronics, but it is fair to say that it is a technology that has a way to go at our level in terms of its application. Some twinkly LEDs are all very well, but unless you have the arrived-on-a-spaceship-from-the-future aesthetic of someone like [Naomi Wu] to carry them off they get old rather quickly.

What the sew-on LED sector of wearable electronics is waiting for are some applications, wearable lights that do something rather than just look pretty. And [Moko] has a project that takes them in that direction, with her color organ dress, a garment whose LEDs react to ambient sound with the aid of a MEMS microphone and an Adafruit Gemma M0 microcontroller board. The LEDs form a color wheel which rotates, and stops at a point proportional to the sound level at the time.

The write-up is an interesting one, going into a little detail as it does in the images on the construction of an electronically-enhanced piece of clothing. Wiring everything up is one thing, but there are other considerations such as the incorporation of extra panels to protect them from mechanical stress, and from sweat. From a dressmaker’s perspective it’s a well constructed garment in its own right with an attractive PCB-style pattern (Where did she get that fabric? Or did she print it herself?) and it appears that she’s the fortunate owner of a serger (overlocker).

Well-assembled clothing has made it here before, for example an impressive jellyfish skirt or this laser-cut arcsin dress. And should you wish to make a garment for your next wearable project, you’ll be sure to need a well-stocked textile bench.

New Part Day: MEMS Loudspeakers

January 16, 2018 by Brian Benchoff 47 Comments

MEMS, or Micro ElectroMechanical Systems, are the enabling technology that brings us smartphones, quadcopters, tire pressure monitors, and a million other devices we take for granted today. At its most basic level, MEMS is simply machining away silicon wafers to make not electronic parts, but electromechanical parts. The microphone in your cell phone isn’t an electret mic you would find in an old brick phone from the 80s — it’s a carefully crafted bit of silicon, packed in epoxy, and hanging off a serial bus.

Despite the incredible success of MEMS technology, there is still something in your smartphone that’s built on 19th-century technology. Loudspeakers haven’t changed ever, and the speaker in your newest iThing is still a coil of wire and some sort of cone.

Now there’s finally a MEMS loudspeaker A company called USound has developed the first loudspeaker that isn’t just a bunch of wire and a magnet. This is a speaker built from a silicon wafer that can be as small as 3 mm square, and as thin as 1 mm. Since these speakers are built on silicon, you can also add an amp right onto the package. This is quite literally a speaker on a chip, and we’d bet that there are already engineers at Samsung looking at stuffing this into a flagship phone.

ST and USound announced these extraordinarily small speakers would actually be made, but so far it’s been just that — an announcement. This changed at CES where ST demonstrated VR goggles with multiple MEMS speakers. Does this mean MEMS speakers are on their way to Mouser and Digikey? We eagerly await the product announcement and demo dev board kit.