Patent ID: 8680452

Claim:
A control device, comprising: an electrically conductive linear guide; a slider unit having a slider connected to the linear guide, a control knob coupled to the slider, and a contact tab coupled to the control knob, the contact tab being electrically connected to the linear guide, the slider unit being moveable linearly along the linear guide; a rack connected at a first portion to the slider unit and being moveable linearly with the slider unit relative to the linear guide to linearly displace the slider unit, the rack comprising a plurality of slots; a control unit with a control circuit electrically coupled to the linear guide and configured to receive an electrical signal from the contact tab through the linear guide; a drive system with a drive element connected to a second portion of the rack spaced apart from the first portion, the drive element being in a fixed position relative to the linear guide, the drive element being operably coupled to the control circuit and activatable to linearly displace the rack to move the slots and position the control knob relative to the linear guide; and an optical detection module in a fixed position relative to the linear guide and spaced apart from the first portion of the rack, the optical detection module being connected to the control unit and configured to detect linear movement of the rack and a position of the control knob based on one or more optical signals detected relative to slots of the rack.