double use fan, for Orca v0.2

Description

My printer 3d (Orca v0.2), has a cooling fan (40x40) that blows air towards the top of hotend (extruder motor area). I realizzaro this project to add air jet on the pieces that are printed, to prevent warping, especially if they are of small size and high print speeds. This project allows you to use a single fan (60x60) for both goals. A flow diverter, activated with a lever, you can choose whether to send only hotend air with the fan running slow, or also on the piece in print. In this case, a microswitch bypasses a resistance and the fan runs at full speed. So for the project you need a resistance of 40Ω (approximately), and a microswitch (I salvaged from an old mouse). Unlike the simple cooling fan directed on the piece in print, this directs to flow where it is needed, avoiding hotend cool. The photo with the two cubes 10x10 (printed at 130 mm/s), show the difference.