[Marthinwurer]

I love these kind of inadvertent measurements. One of my favorite examples is that a sufficiently accurate IMU can get you relatively accurate longitude measurements from the Coriolis effect.

[adolph]

Slight correction, latitude, not longitude.

The earth’s surface closer to the poles has less distance to travel for any rotation than the surface closer to the equator. As a result the inertial navigation systems of long distance systems must be adjusted. Iirc, this is also the case for artillery firing computations.

https://www.oxts.com/blog/going-round-circles-earth-rotation...

https://www.britannica.com/science/latitude

[billyjmc]

Coriolis corrections are thrown into sniper ballistic calculations, too. Not a huge effect in most conditions, but not zero, and there have been a lot of long shots in the past two decades.

[nielsole]

Asahi Linux (and likely MacOS too) uses the resistance of the speakers coils to detect overheating of same speakers and reduces volume.

[squarefoot]

That's the same principle used by cheap solder stations to regulate the tip temperature without employing a thermal sensor: they measure the heater resistance, presumably during the off state of the PWM signal that drives the heater. In that case the measurement is less accurate than using a real sensor, still good enough for cheap solder stations where a few degrees don't make a big difference.

[derhuerst]

https://github.com/AsahiLinux/speakersafetyd

[nick3443]

Also used in electric motor controllers to monitor winding temperature.

[01HNNWZ0MV43FF]

Is that the same thing where a flat-earther tried to measure something with an expensive laser gyro and kept finding that Earth was rotating?

[adolph]

I think the most you can tell from an IMU or gyro is that there is a change in velocity in a direction aligning with East-West when there is a change in location and that the change in velocity is greater when the location changes in line with North-South. The change in velocity would be greater as one approaches the poles and lesser at the equator.

Thought experiment: if I zeroed my IMU at the North pole and traveled in a straight line away from the pole along longitude zero, following the guidance of the IMU. By the time I got to 45° latitude I’d be traveling Westward at 1,180 kph (.95 Mach) to keep the IMU at zero.

[psunavy03]

I believe this is one of the initial steps an aircraft INS uses to find north while it is aligning, but it's been too long since I had aircraft systems theory in the front of my brain.

[t0mas88]

Yes, from earth rotation the INS could figure out true north if the latitude is known. Or figure out the latitude if current heading is known. But normally it's aligned with a starting position from pilot input or GPS.

[emptiestplace]

https://en.m.wikipedia.org/wiki/Inertial_measurement_unit

[cameldrv]

Latitude or Longitude?

[sam_dam_gai]

Do you mean latitude?