A spool brake device for a fishing reel includes an electric spool brake, a rotation detector, and a controller. The rotation detector detects a rotation of the spool. The controller calculates a rotational velocity of the spool based on the rotation of the spool, determines whether the fishing reel is in a casting state based on the rotational velocity, controls the spool brake to brake the spool upon a determination that the fishing reel is in the casting state, and controls the spool brake to not brake the spool upon a determination that the fishing reel is not in the casting state.

An angular position is determined for an electronic module fixed to the inner face of the tread of a tire fitted to a wheel of a vehicle. A sensor for measuring the radial acceleration of the wheel is integrated into the electronic module, and a variation of the radial acceleration is detected that corresponds to a position of the electronic module when it contacts the ground. This variation is used to determine a frame of reference defined by an origin and a reference unit corresponding to an angular sector of the tire having a length is shorter than a mean length of the footprint of the grounded tire, in order to determine angular positions of the electronic module in the frame of reference.

Disclosed herein are systems and methods for calculating angular acceleration based on inertial data using two or more inertial measurement units (IMUs). The calculated angular acceleration may be used to estimate a position of a wearable head device comprising the IMUs. Virtual content may be presented based on the position of the wearable head device. In some embodiments, a first IMU and a second IMU share a coincident measurement axis.

Disclosed herein are systems and methods for calculating angular acceleration based on inertial data using two or more inertial measurement units (IMUs). The calculated angular acceleration may be used to estimate a position of a wearable head device comprising the IMUs. Virtual content may be presented based on the position of the wearable head device. In some embodiments, a first IMU and a second IMU share a coincident measurement axis.

An electronic module to automatically determine is position within a vehicle is provided. The electronic module includes a plurality of input connectors comprising an I/O interface for a vehicle wiring harness, the electronic module also including an accelerometer to provide an additional datum point. Based on the accelerometer output, the electronic module can determine if it is facing inward, toward the center of the vehicle, or facing laterally outward. In this respect, the electronic module can convert an n-bit I/O interface into an n+1 bit I/O interface to thereby double the number of locations that are detectable by the electronic module. For wiring harnesses limited to two physical pins, for example, only four locations are normally detectable, but with the additional accelerometer input, eight locations are detectable. As a result, the same electronic module can be used for up to eight locations, thereby simplifying installation.