Maybe attack the problem from a different angle: use an accelerometer. Or spend a little bit more money to add a gyro and make a real, if very low accuracy, IMU.
That is a great suggestion. I think Android just implemented a “snatch detection” system for phones. Although, I like the idea of not requiring additional hardware. I guess when I start running a drug empire I will have to pony up for the extra dongle.
Some HSMs I've used (payshields) have tamper sensors that can detect motion for this reason.
> The ADXL362 accelerometer in the PayShield 10K acts as a "Motion Sensor" detecting tilt movements. An alarm triggers an alert if the HSM is moved (for example, slid out of the rack)
Rotation itself isn’t a threat, but if you want to directly estimate displacement to distinguish between earthquakes and someone stealing the machine, without relying on heuristics, actual inertial measurement would do the trick. And inertial measurement involves tracking the direction of acceleration, which involves tracking rotation.
