editor's blog
Subscribe Now

A Non-MEMS Magnetometer

We’ve spent a lot of time talking about MEMS in these pages, but not all sensors are MEMS. At Semicon West, I got to talk to Becky Oh of PNI Sensors. They make geomagnetic sensors with noise characteristics around 30 times better than Hall-effect sensors, as she tells it. But they’re not MEMS sensors.

They use a material whose permeability changes with the magnetic field. They wrap this material in a coil and then put the resulting variable inductor in an RLC tank and use the oscillation frequency as an indicator of the magnetic field.

Of course, like all sensors, they need software. They include low-level code that corrects for local magnetic anomalies, although, on its own, the sensor needs some movement to calibrate itself. Combined with a gyro and accelerometer, they can distinguish between an external field change and actual movement of the sensor.

Given the discussions we’ve had on sensors being different from each other, making universal fusion harder, her perspective was that the data returned by sensors are generally quite similar: it’s the APIs that tend to vary. And, of course, software uses APIs, not data directly, so those calls end up masking the similarities between sensors.

Given the size of their sensors (not huge, but not MEMS), they’re not looking to sell into phones. They have background in military, navigation, and virtual reality applications; they’re looking to grow further into games and TV controllers. These are somewhat more forgiving than some of their earlier markets in that they are, more or less, pointing applications, and absolute heading isn’t critical for those apps in the way it is for navigation apps.

They’re building a new fab in Santa Rosa, CA. It seems to be part of a trend to bring manufacturing back to the US – as long as the manufacturing line itself doesn’t require hiring any real people. The key to these fabs is automation: everything is done by computer. There is a need for a hundred or so well-trained people that can work (and repair) the equipment, which is less than would have been used in the past or overseas, but more than would be in the US if they remained overseas.

Even though they aren’t MEMS, they’re joining the MEMS Industry Group, since there’s a lot of commonality with the ecosystem and other players there. And it appears that the Group will let them in…

Leave a Reply

featured blogs
Mar 26, 2019
It's CDNLive! Well, not today, Tuesday and Wednesday, April 2nd and 3rd at the Santa Clara Convention Center. So I have eight things you can do to get the most out of CDNLive and go home with a... [[ Click on the title to access the full blog on the Cadence Community si...
Mar 25, 2019
Do you ever use the same constraint templates in multiple projects? Now, with PADS Professional VX.2.5, you can easily import and export constraints from one project to the next. Constraint templates enable application of complex rules to multiple nets. They help ensure a smo...
Mar 22, 2019
In the video above, it might not appear that much is taking place, but just like with transformers there is “more than meets the eye.” Alright, that was corny, and I am mildly ashamed, but Nanosecond Event Detection for shock and vibration is nothing to be ashamed...
Jan 25, 2019
Let'€™s face it: We'€™re addicted to SRAM. It'€™s big, it'€™s power-hungry, but it'€™s fast. And no matter how much we complain about it, we still use it. Because we don'€™t have anything better in the mainstream yet. We'€™ve looked at attempts to improve conven...