editor's blog
Subscribe Now

What’s In a Name

We’re all still getting calibrated on sensors, and we can sometimes get tripped up on terminology. In discussions about their sensor fusion IP, Movea explicitly included some definitions to make sure we were aligned.

Most prominent is their finessing of the mythical 9-axis or 9-DoF sensor. They do this by distinguishing between true degrees of freedom and axes. Spatial motion involves only six true degrees of freedom: 3 dimensions linear and three dimensional rotational. That’s all there is. The problem is that when accelerometers (which handle 3D linear) and gyroscopes (which handle 3D rotational) are joined by magnetometers, which also position in 3 dimensions, many marketers blithely add the degrees of freedom together to get 9 of them.

The problem is, the magnetometer’s three degrees of freedom overlap those of the other two sensors. We haven’t magically entered a new world that has three completely new ways of moving; we’re just getting a new view of the existing six degrees of freedom.

Movea is more permissive with the term “axis,” allowing each sensor its own axes and making them additive. So an accelerometer/gyroscope/magnetometer combo, in their parlance, has six degrees of freedom and nine axes.

Other lexical distinctions they provide:

–          Axial sensors, which provide, essentially, a vector result, with a value for each axis; versus scalar sensors, like pressure sensors, which simply provide one number as a result

–          Motion sensing categories, from detection, which is Boolean – either there is motion or there isn’t – to classification, which categorize movements like gestures into discrete buckets, to estimation, where a value from a continuous range is reported – part of what separates full motion processing from gesture recognition.

Leave a Reply

featured blogs
Sep 25, 2020
What do you think about earphone-style electroencephalography sensors that would allow your boss to monitor your brainwaves and collect your brain data while you are at work?...
Sep 25, 2020
Weird weather is one the things making 2020 memorable. As I look my home office window (WFH – yet another 2020 “thing”!), it feels like mid-summer in late September. In some places like Key West or Palm Springs, that is normal. In Pennsylvania, it is not. My...
Sep 25, 2020
[From the last episode: We looked at different ways of accessing a single bit in a memory, including the use of multiplexors.] Today we'€™re going to look more specifically at memory cells '€“ these things we'€™ve been calling bit cells. We mentioned that there are many...
Sep 25, 2020
Normally, in May, I'd have been off to Unterschleißheim, a suburb of Munich where historically we've held what used to be called CDNLive EMEA. We renamed this CadenceLIVE Europe and... [[ Click on the title to access the full blog on the Cadence Community site...

Featured Video

Product Update: Synopsys and SK hynix Discuss HBM2E at 3.6Gbps

Sponsored by Synopsys

In this video interview hear from Keith Kim, Team Leader of DRAM Technical Marketing at SK hynix, discussing the wide adoption of HBM2E at 3.6Gbps and successful collaboration with Synopsys to validate the DesignWare HBM2E IP at the maximum speed.

Click here for more information about DesignWare DDR IP Solutions

Featured Paper

4 audio trends transforming the automotive industry

Sponsored by Texas Instruments

The automotive industry is focused on creating a comfortable driving experience – but without compromising fuel efficiency or manufacturing costs. The adoption of these new audio technologies in cars – while requiring major architecture changes – promise to bring a richer driving and in-car communication experience. Discover techniques using microphones, amplifiers, loudspeakers and advanced digital signal processing that help enable the newest trends in automotive audio applications.

Click here to download the whitepaper

Featured Chalk Talk

High-Performance Motor Control Solutions Through Integration

Sponsored by Mouser Electronics and Qorvo

Brushless motors have taken over the market for a huge number of applications these days. But, it’s easy to blow up your BOM cost with all the motor control and power management components required. In this episode of Chalk Talk, Amelia Dalton chats with Marc Sousa of Qorvo about the Power Application Controller (PAC) that can lower your BOM, trim down your component list, and give you several other benefits as well.

Click here for more information about Qorvo Power Application Controllers®