Cable tension monitor

A movable barrier system comprising:

• a movable barrier operator configured to move a movable barrier in a first direction and a second direction;
• an elongate member capable of being connected to the movable barrier;
• a rotatable drum rotatable about an axis and having an external surface configured to receive the elongate member thereon, the external surface extending about the rotatable axis and having a predetermined width along the axis;
• the elongate member configured to wind up on and pay out from the external surface of the rotatable drum to at least support corresponding movement of the movable barrier;
• and
• a sensor apparatus comprising a sensing portion configured to extend across the external surface of the rotatable drum, the sensing portion configured to sense a first radial distance between the elongate member and the sensing portion at a plurality of sensing regions along a central longitudinal axis of the sensing portion, wherein the sensing portion includes a capacitive sensor, an inductive sensor, or a combination thereof, wherein the sensing portion is shapeable to complement the external surface of the rotatable drum and be radially spaced therefrom;
• and
• a controller connected to the sensing portion, the controller configured to receive information from the sensing portion to detect the elongate member moving radially closer to any of the sensing regions along the width of the external surface of the rotatable drum upon the sensing portion sensing the elongate member at a shorter, second radial distance from the sensing portion, the controller configured to detect the elongate member moving radially closer to the sensing portion without the elongate member contacting the sensing portion,
• wherein the controller is further configured to effect, by the movable barrier operator, at least one of a stoppage of rotation of the rotatable drum and a reversal of rotational direction of the rotatable drum in response to the elongate member moving radially closer relative to the sensing portion according to the information received from the sensing portion.

A method comprising:

• sensing, by a sensor, a first spaced apart radial proximity of an elongate member connected to a rotatable drum relative to a shapeable sensing portion of the sensor, the shapeable sensing portion having a first shape wherein the shapeable sensing portion is configured to be positioned at the rotatable drum, the shapeable sensing portion shapeable to a different, second shape that complements an external surface of the rotatable drum after positioning the shapeable sensing portion at the rotatable drum, the sensing portion in the second shape spaced radially from the rotatable drum;
• sensing, by the sensor, a second spaced apart radial proximity of the elongate member relative to the shapeable sensing portion in the second shape, the second spaced apart radial proximity less than the first spaced apart radial proximity;
• in response to sensing the second spaced apart radial proximity less than the first spaced apart radial proximity, determining the elongate member moving radially closer to the shapeable sensing portion of the sensor;
• and
• transmitting a signal to effect at least one of a stoppage of the rotatable drum and a reversal of rotational direction of the rotatable drum in response to determining the elongate member moving radially closer to the shapeable sensing portion.