Lens adapter for Acer K137 projector

This is the remix of an existing design. Thanks to the original owner
The lens is intented to be used with DAVID SLS Scanning system, to be able to reduce focusing distance (with a set of 37mm close up lenses) and therefore scanning smaller objects.

The improvement I propose consists on:
- Suitable to Acer K137 projector
- Features a slotted tab at the bottom which helps to fix the adapter to the projector lower -central stand point (adjustable)