July 2013 – EEJournal

What Is “Good” Yield?

July 31, 2013

In a recent piece on antenna tuning, I addressed circuit and MEMS approaches, and one of the advantages of circuits was said to be better yield. So I contacted the MEMS folks in that space for their comments on yield, and I received a carefully-worded comment from Cavendish Kinetics (and none from WiSpry).

I interpreted the Cavendish comment as basically acknowledging that yields weren’t great but were on a typical learning curve. Well, it turns out that interpreting the comments as saying … Read More → "What Is “Good” Yield?"

Sensor Driver? Sensor Fusion?

by Bryon Moyer

July 30, 2013

Not long ago, coincident with Sensors Expo, Freescale announced their new Intelligent Sensing Framework, or ISF. From the initial descriptions I saw, I was frankly a bit confused as to how this is different from a driver and from other sensor fusion solutions. A conversation with Freescale’s Jim McGlasson helped add some color to what’s going on.

As a starting point, we can remind ourselves that a driver is a piece of code running on a host (or AP or whatever) that lets that host access a resource. In the case of a sensor, the … Read More → "Sensor Driver? Sensor Fusion?"

Cache Clunker

by Bryon Moyer

July 25, 2013

We all know that server computing and embedded computing are different for lots of reasons, many of which can be summed up in one word: budget. Memory budget, performance budget, cost budget, etc. In other words, embedded systems have tight budgets, servers (and desktops and laptops) don’t. Much.

But occasionally something whacks you across the head in terms of the difference. Not long ago, there was an announcement out of MIT about a way to disguise memory access patterns for security. The deal is that, even when you’ve taken careful measures to encrypt data and … Read More → "Cache Clunker"

Could Mechanical Replace Electrical?

by Bryon Moyer

July 24, 2013

The MEMS Industry Group sponsored a webinar recently with a focus on switches. Literally; mechanical switches. Just really tiny ones made of a beam that can be actuated by an electrical signal.

OK, so I guess it’s not completely mechanical, it’s electromechanical, but the suggestion is that you could configure complete circuits with these.

The presenter was Maarten De Boer of CMU, and he painted a picture of what could happen with the continued evolution of micro- and nanoswitches. The “pros” of such an approach are:

Lower power (only needed … Read More → "Could Mechanical Replace Electrical?"

QTC Moves to the Screen

by Bryon Moyer

July 23, 2013

Not long ago we looked at Peratech’s QTC technology. You might remember it as a functional ink that’s highly sensitive to pressure. Our focus at the time was how the technology works; designs seemed to be in process at that point.

Shortly after, they announced a touch screen solution. Because of the ink’s sensitivity, they can actually put the touch sensor behind the screen, reducing the cost of the screen itself and getting the electronics out of the … Read More → "QTC Moves to the Screen"

Antenna Tuning Without MEMS

by Bryon Moyer

July 22, 2013

Quite some time ago, we reported on WiSpry, a MEMS company that was using its technology to switch capacitors so that the antenna tuning can be optimized and changed in real time as conditions and needs change.

Much more recently, a new solution was announced based on collaboration between Taoglas, who makes antenna assemblies, and Peregrine, who produces an array of digitally-switchable capacitors (amongst other things). They’ve combined the two into a module that can fit into phones … Read More → "Antenna Tuning Without MEMS"

A Reverse Proof Mass?

by Bryon Moyer

July 18, 2013

This continues both the theme of “stuff at Sensors Expo” and non-traditional approaches to common sensors. Only this time, it’s the most ubiquitous of motion sensors, the accelerometer.

Most accelerometers use some sort of “proof mass,” a piece of silicon or metal or quartz or… whatever. Inertia makes the proof mass “move” in the opposite direction of acceleration, and you can measure that apparent movement.

Memsic (whose … Read More → "A Reverse Proof Mass?"

Am I Spoiled Yet?

by Bryon Moyer

July 17, 2013

From the Sensors Expo files, I saw another interesting integration from ams for use with perishable products. It’s an RFID/temperature sensor combination with some smarts. It’s a tag you put on the packaging for a specific product to monitor the temperature history of the product.

In other words, this isn’t about alerting that, “It’s getting hot in here, so… turn up the A/C!” While you can specify high and low triggers, more interestingly, the mini-system has an Arrhenius “calculator” built in. Whoever installs a specific tag for a specific product initializes … Read More → "Am I Spoiled Yet?"

A Move Towards a Magnetic MEMS Relay

by Bryon Moyer

July 16, 2013

Relays might seem amongst the most mundane of components, and yet even they are getting a miniaturization upgrade with the help of MEMS technology. Of course, you might reasonably ask, since reed relays are already mechanical devices, why not simply make them smaller? And there’s a very specific reason: The reed is encased in glass, and that glass is fused onto the leads, which have rhodium or ruthenium or iridium on the contacts. That fusing process is hot, and if you shrink the relay too much, that heat gets too near the contacts and the metal melts.

< … Read More →

Mag Sensor for Watch Compass

by Bryon Moyer

July 11, 2013

Continuing with the series of Sensors Expo conversations, I had a chance to discuss a couple of topics with Memsic (one of which we’ll talk about in a future entry). Today we’ll look at their magnetic sensor, which relies on AMR – anisotropic magneto-resistance.

Currents generate magnetic fields, but with AMR, the difference in direction by the field generated by current and some external field will impact the resistance of the material. Current is generally run at an angle in stripes of … Read More → "Mag Sensor for Watch Compass"