Abstract: A resistance welding method comprises firstly lapping weldments in an up-down crossing manner or an overlapping manner, and then prepressing two electrodes in the same direction onto a top-layer weldment to form a current loop. A pressurization sheet made of a high resistance high-temperature resistant material which is parallel to the electrodes and is capable of moving upward and downward and applying a pressure to the welding position is arranged on the same side of the electrodes and between the two electrodes. The welding comprises the following steps: switching on a power supply of a welding machine, generating, by the current, resistance heat in the top-layer weldment to heat the top-layer weldment to a melting or plastic state; applying, by the pressurization sheet, a pressure to the top-layer weldment; cooling to crystallization; releasing the pressure applied by the pressurization sheet and the two electrodes and taking out the weldment.

Abstract: A vehicle backup alert system using messaging system that announce the distance between the vehicle and an obstacle therebehind. A main control unit (MCU) powered by the vehicle battery, controls a speaker positioned in the vehicle cabin and at least one ultrasonic transducer mounted on the exterior of the vehicle and positioned to generate sound waves that scan a wide field of view behind the vehicle. The MCU is activated when the vehicle is in reverse. Once activated, the MCU causes a sensor to generate a sensor signal which is incident on an obstacle (if present) behind the vehicle. The signal reflected from the obstacle is processed and fed back to the MCU. The MCU software then determines if the echo signal has detected an object. If yes, the voice module is activated and the speaker announces the distance to the object in a variable tone and the cycle is repeated. If the echo signal has not detected an object and the object has not moved into a blind area, the signal is again transmitted by the MCU.