Ultrasonic sensor - Wikipedia, the free encyclopedia

An ultrasonic transducer is a device that converts energy into ultrasound, or sound waves above the normal range of human hearing. While technically a dog whistle is an ultrasonic transducer that converts mechanical energy in the form of air pressure into...

這樣會永遠聽不到吧~~

這樣會永遠聽不到吧~~...

宿舍禁止用冰箱怎辦

宿舍禁止用冰箱怎辦.......

這....輪胎不會爆喔~~

這....輪胎不會爆喔~~?!!...

不會吧 小寶寶也需要檢查

不會吧!小寶寶也需要檢查...