Filament Speed Measurement Device Shell

耗材测速用的，这是外壳，还需要五金件弹簧2*8*0.1，还需要激光测速（巡线小车的遮光轮测速）的模块，在淘宝和亚马逊就可以买到。Consumable speed measurement, this is the shell, but also need hardware spring 2*8*0.1, but also need laser speed measurement (light wheel measurement of the patrol car) module, in Taobao and Amazon can be bought.