Similar to the action of human operators in commercial rice mills, it was necessary to take a sample from the discharging grains to assess the quality of the milled rice and adjust machine performance, accordingly. To achieve this goal in an automatic manner, a mechanism was designed and constructed. In this mechanism, the kernels were delivered through an orifice whose flow was regulated by a shield activated by a stepper motor. Consequently, a certain amount of milled rice kernels was delivered through the branch channel onto the singulation unit.