Abstract: The upper channular frame supporting the venetian blind houses a rotary shaft parallel to the slats of the blind and from which the slats are suspended by a pair of nylon ladders. The shaft is driven by a small D.C. motor and gear reduction unit having an output governed by limit switches selectively operable to provide a predetermined limit of angular slat movement. The limit switches are incorporated in parallel branches directly in one of the power lines to the motor, with individual diodes controlling the direction of the current through the corresponding branches.