Abstract: Disclosed in the embodiments of the present application are a mechanical zero position calibration method and apparatus, and a device and a medium. The method comprises: controlling a target electric motor to drive an instrument joint of a target instrument to respectively move in at least two set directions, and determining joint torque change information corresponding to each set direction; determining critical point information, corresponding to each set direction, of the instrument joint on the basis of the joint torque change information corresponding to each set direction; and determining, according to the critical point information corresponding to each set direction, an electric motor position corresponding to a mechanical zero position of the target instrument.

Abstract: A color wheel phase detection method and system, and a projection device. The phase detection system comprises a color wheel (1), a color wheel motor (2) that drives the color wheel (1) to rotate, and a control circuit (3); the color wheel motor (2) is a three-phase motor, and the control circuit (3) comprises a three-phase driving circuit (31) for driving the color wheel motor (2) to operate. The phase detection system further comprises a phase detection device (4) for detecting the three-phase driving circuit (31); when detecting a preset phase, the phase detection device (4) sends a pulse signal to the control circuit (3) to implement color wheel phase detection. Therefore, the effects of low costs, high accuracy, and high reliability are achieved.

Abstract: A color wheel phase detection method and system, and a projection device. The phase detection system comprises a color wheel (1), a color wheel motor (2) that drives the color wheel (1) to rotate, and a control circuit (3); the color wheel motor (2) is a three-phase motor, and the control circuit (3) comprises a three-phase driving circuit (31) for driving the color wheel motor (2) to operate. The phase detection system further comprises a phase detection device (4) for detecting the three-phase driving circuit (31); when detecting a preset phase, the phase detection device (4) sends a pulse signal to the control circuit (3) to implement color wheel phase detection. Therefore, the effects of low costs, high accuracy, and high reliability are achieved.

Abstract: This application provides a speaker and a sound diffuser thereof. The sound diffuser includes a first diffusion surface and a second diffusion surface. The first diffusion surface faces toward a first driver, and has a first central area that is a circular protrusion, a first outer ring region, and a first concave ring region located between the first central area and the first outer ring region. The second diffusion surface faces toward a second driver, and is a circular dish surface protuberant from center outwards. The sound diffuser is coaxially located between the first driver and the second driver, and the first driver and the second driver respectively generate different sound production frequencies.

Abstract: This application provides a speaker and a sound diffuser thereof. The sound diffuser includes a first diffusion surface and a second diffusion surface. The first diffusion surface faces toward a first driver, and has a first central area that is a circular protrusion, a first outer ring region, and a first concave ring region located between the first central area and the first outer ring region. The second diffusion surface faces toward a second driver, and is a circular dish surface protuberant from center outwards. The sound diffuser is coaxially located between the first driver and the second driver, and the first driver and the second driver respectively generate different sound production frequencies.