A device of or attached to a roller body determines a rotational frequency of the roller body (or other object) rotating about an axis of rotation includes an acceleration sensor that detects an acceleration signal of an acceleration in a first direction extending in a radial or tangential direction to the axis of rotation of the roller body; and an electronic processing unit and configured to low-pass and high-pass, particularly adaptively high-pass filter, the detected acceleration signal, perform a derivation, with respect to time, of the filtered signal, optimize the signal with a subsequent absolute-amount generation and with moving averaging, and ascertain a frequency of the filtered acceleration signal, which corresponds to the rotational frequency of the roller body.

A device of or attached to a roller body determines a rotational frequency of the roller body (or other object) rotating about an axis of rotation includes an acceleration sensor that detects an acceleration signal of an acceleration in a first direction extending in a radial or tangential direction to the axis of rotation of the roller body; and an electronic processing unit and configured to low-pass and high-pass, particularly adaptively high-pass filter, the detected acceleration signal, perform a derivation, with respect to time, of the filtered signal, optimize the signal with a subsequent absolute-amount generation and with moving averaging, and ascertain a frequency of the filtered acceleration signal, which corresponds to the rotational frequency of the roller body.

A putting practice apparatus for evaluating the striking speed and tempo of a putter includes: an emitting unit (100) that emits light and is provided in a first sensor installation part; a light receiving unit (200) that receives the light emitted from the emitting unit (100); a speed detecting unit (300) and a position measuring unit (400) which respectively detect the speed and measure the position of the golf ball (1); a calculation control unit (500) for performing calculations in order to detect the initial position value of the golf ball (1) as measured by the position measuring unit (400) and the movement speed (Vb) and the moving distance (Hb) of the golf ball (1) as measured by the speed detecting unit (300); and a storage unit (600) for storing the measured speed (Vb) and the measured distance (Hb) of the golf ball (1).

A speed sensor, a device for measuring a speed, and a method for measuring a speed are provided. The speed sensor includes: an imaging device; a liquid crystal lens on a side of the imaging device; and a controller configured to: apply different voltages to the liquid crystal lens, obtain, via the imaging device, images of a reference object formed through the liquid crystal lens under the different voltages, control, based on information of the images, the liquid crystal lens to realize focus for multiple times for the reference object, obtain a voltage that is correspondingly applied to the liquid crystal lens when each of the multiple times of focus is realized, and calculate a speed based on the voltages.

A speed sensor, a device for measuring a speed, and a method for measuring a speed are provided. The speed sensor includes: an imaging device; a liquid crystal lens on a side of the imaging device; and a controller configured to: apply different voltages to the liquid crystal lens, obtain, via the imaging device, images of a reference object formed through the liquid crystal lens under the different voltages, control, based on information of the images, the liquid crystal lens to realize focus for multiple times for the reference object, obtain a voltage that is correspondingly applied to the liquid crystal lens when each of the multiple times of focus is realized, and calculate a speed based on the voltages.

A method, system, and apparatus for determining the location of a tool traveling down a wellbore by measuring a first borehole magnetic anomaly with respect to time at two known locations on a tool, comparing the time difference between the two measurements, then calculating the velocity of the tool based on the comparison, then further calculating the distance traveled by the tool in the wellbore based on the velocity calculation, then executing a series of commands at a predetermined location in the wellbore.

An exerciser includes: sensor installation units provided to be spaced apart from and face each other in a direction parallel; a radiation unit for radiating light, in a first sensor installation unit; a light receiving unit for receiving the light radiated from the radiation unit, in a second sensor installation unit; a speed detection unit for detecting a speed of the golf ball by checking a moment the golf ball passes; a position measurement unit for measuring a position of the golf ball; an operation control unit for performing calculation to detect an initial position value of the golf ball and a moving speed Vb and a moving distance Hb of the golf ball; and a storage unit for storing the measured speed Vb and distance Hb of the golf ball.

Systems and methods for use in determining a device's speed. The system uses a plate having a front side that is perpendicular to the device's direction of travel. The airflow caused by the device's motion causes the plate to deflect from a resting position and the amount of deflection of the plate is proportional to the speed of the device. The amount of deflection is measured by a rotary encoder coupled to the plate. By properly calibrating the system, the system can determine the device's velocity simply from the airflow caused by the device's motion.

Systems and methods for use in determining a device's speed. The system uses a plate having a front side that is perpendicular to the device's direction of travel. The airflow caused by the device's motion causes the plate to deflect from a resting position and the amount of deflection of the plate is proportional to the speed of the device. The amount of deflection is measured by a rotary encoder coupled to the plate. By properly calibrating the system, the system can determine the device's velocity simply from the airflow caused by the device's motion.

A road surface condition identification apparatus for identifying a road surface condition is provided. The road surface condition identification apparatus includes a vibration detector unit configured to output a detection signal being an analog signal according to magnitude of vibration of the tire. For identifying the road surface condition, the road surface condition identification apparatus performs A-D conversion of converting the detection signal of the vibration detector unit into a digital signal. Based on data on vehicle speed, the road surface to condition identification apparatus sets a conversion range of the magnitude of the vibration of the tire used in the AD conversion from the detection signal into the digital signal.