I want to build a kind of a Guillotine - a project that holds a weight, can let it free fall and can lift it again. Holding a weight of 20 gram and falling length of 20cm is OK, 100-200 gram is great.
The lifting process can be slow (2-3 seconds is Ok, max 67-7 seconds). Alternatively having a stack of a few weights and letting only 1 fall at a time is also good for me.
Do you have any ideas how to implement it with an Arduino?