This is a functional micro servo valve to be used with silicon tubing 6mm OD. It is designed around the powerfull MG92B micro servo.
SG90 micro servos (wich are of the same dimensions as the ones I've used) are also compatible but I'm not sure if they are strong enough to close the valve. Any feedback would be appreciated.
This design is inspired by the LEGO NXT motor valve (by Irah) and the Borud Tube Valve Prototype 2 (by Borud).