磁性抓手

国外的达人就是多，不断的加入新元素。这个视频中使用了磁性原理。

这里有一段文字描述，感觉很专业，哪天花些时间翻译一下。
Elco used a magnetic latching solenoid to build a magnetic grabber. The solenoid used is designed for low duty cycle applications where the solenoid’s energized position is needed for an extended period of time. The plunger latches magnetically in his basic position, until a negative electrical pulse is applied to allow the plunger to unlatch. Elco also build a mechanical guiding system to allow the plunger to reliable enter the hole of the solenoid.