Wall Switch Lockout

thingiverse

I sometimes use my basement as a darkroom and need a way of indicating to my housemates that they shouldn't try to turn on the light; this is that. This is printable as two parts: A plate you can screw to your wall switch. A clasp (attached to the above plate by a hinge -- use a ~1.5mm pin for connecting the clasp to the plate) that, when closed, prevents the switch it is attached to from being switched from its current position.