A controller apparatus for controlling IoT devices has a rotation disk, a rotation detection circuit, a control circuit, a wireless circuit, a circuit board and a housing. The rotation disk has a rotating shaft in an inner surface of the rotation disk for generating a rotation operation, where the rotation operation is either a clockwise rotation or a counterclockwise rotation. The rotation detection circuit is used for detecting the rotation operation of the rotating shaft. The control circuit retrieves the rotation operation from the rotation detection circuit, and generates a control instruction according to the rotation operation to the wireless circuit to control a corresponding external device.

A calibration method for compensating a home position of a 3D printer is disclosed. According to a movement position of a movable mechanism of the 3D printer, a control voltage is provided to a microcontroller. The calibration method includes steps as follows. The movable mechanism moves in a home direction. It is to determine whether the microcontroller receives a first logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves in a direction opposite to the home direction. It is to determine whether the microcontroller receives a second logic level signal which is transited according to the corresponding control voltage. If yes, the movable mechanism moves a compensation distance corresponding to a step compensation amount in the home direction. Therefore, the calibration method is provided to reduce circuit costs, simplify designs of control circuits, and accurately calibrate the home position.

A gravity center adjustable device comprises a driving member, and two gravity center adjusting members. The driving member comprises a driving main body, two transmission shafts, and two gear wheels. Each gear wheel is coiled around a transmission shaft. Each gravity center adjusting member comprises a gravity center adjusting shaft, and two weight balls. The gravity center adjusting shaft comprises a rack shaft, teeth of the rack shaft are engaged with those of the gear wheel, thus when the gear wheel rotates, the rack shaft will move around along its own axial relative to the gear wheel. A gravity center self-adjusting device and an electronic device using the gravity center adjustable device are also provided.

A motor controller includes memory, and processing circuitry that controls a motor based on a position command and based on a position detection value corresponding to a detected position of the motor, calculates a tolerance position error in a successive manner based on the position command and based on a control parameter used to control the motor, calculates a position error maximum threshold that depends on the tolerance position error, detects an abnormality based on the position error maximum threshold, and triggers an indication when the abnormality is detected.

To provide an air vehicle configured to stabilize the power output of a fuel cell by securing the generated water discharge property of the fuel cell. An air vehicle, wherein the air vehicle comprises two or more fuel cells; wherein each fuel cell comprises an anode outlet manifold; and wherein each fuel cell is disposed in the air vehicle so that water discharge directions of the anode outlet manifolds are different from each other.

A control method includes receiving trigger information that initiates movement of the display screen, generating a driving signal based on the trigger information to control a drive motor that moves at least one end of the display screen and monitoring the state of a target limit switch configured to limit movement of the display screen to a target position. The driving signal controls a drive motor to move at least one end of the display screen. A first signal is generated based on a state of the target limit switch switching from a first state to a second state. The switching of the target limit switch from the first state to the second state indicates that a movement position of the display screen has changed from not reaching the target position to reaching the target position.